PC Archeology: The plasma screen is probably the best thing about Schneider PC 7640
I take a deep dive into this laptop, the Schneider PC 7640. While it's extremely heavy and doesn't even run on batteries, it does have a much sought after gas plasma screen onboard. Watch while I struggle to get this machine working so I can finally try out some software on it in all that plasma glory. (And realize that maybe gas plasma screens aren't actually so great, even when they work correctly.)
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Samsung S5200 Laptop:
Part 1: • Does this dead "laptop...
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Service manual and disks:
archive.org/details/schneider...
Yamaha video chip can drive the screen at 640x400:
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Detailed pictures of the entire machine:
fuz.su/~fuz/pic/pc7640/
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Deoxit D5:
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O-Ring Pick Set: (I use these to lift chips off boards)
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Elenco Electronics LP-560 Logic Probe:
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Hakko FR301 Desoldering Iron:
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Rigol DS1054Z Four Channel Oscilloscope:
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Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
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TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
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TS100 Soldering Iron:
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EEVBlog 121GW Multimeter:
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DSLogic Basic Logic Analyzer:
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Magnetic Screw Holder:
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Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
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RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
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Plato (Clone) Side Cutters: (order five)
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Heat Sinks:
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Little squeezy bottles: (available elsewhere too)
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--- Instructional videos
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• How to remove chips wi...
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Hi Adrian, I'm not a power supply engineer, per se, but an electronics engineer with 80's era switch mode power supply design experience. There are two potential issues I can think of when running switching supplies below their rated voltage. One is that, switch-mode supplies are "constant power" devices, so they will draw more current as input voltage is lowered. That could overheat input circuit components or blow a fuse, if running well below rating. The second issue is that these supplies typically regulate output voltage by adjusting pulse width to a step-down transformer. Lower input voltage causes the pulse-width to increase, thus increasing the peak magnetic field strength in the transformer core. There is a maximum pulse-width, which will cause the transformer core to saturate. Saturation causes the primary's impedance to drop rapidly (essentially, becoming a wire), which would then drastically increases current flow. If a current limiting measure is not implemented, this could damage components. This saturation effect would also happen if supply output is shorted. I bet that any PC power supply would have active over-current / under-voltage protection, beyond just a fuse, but can't guarantee. Keep up the amazing work!
This info is accurate. Most likely you won’t have an issue, but you should check if something gets hot. The issue is that when the voltage in goes down the current will increase to deliver the same wattage. It could saturate the transformer. If that happen the supply will collapse and you can see it as it restarting in a loop. But if the transformer don’t have an issue with it then do check that nothing get too hot on the “primary” side since you are running it with an higher current.
@@pederb82 And this would indeed apply more on older SMPS than newer ones. Newer ones often use integrated controllers, some of which take note of the input voltage and limit their power output accordingly if it drops beyond an acceptable level. Others (like high power ATX supplies) use active PFC, which functions more or less as a DC boost converter before the main switching circuit. These are very often labeled as universal voltage, because at that point it's silly not to account for it. All in all, I'd still argue that only a subpar power supply design would stand vulnerable to this, but the older the supply the more expensive it was to implement back then.
I spent more than 20 years working for two SMPS design companies. This information is 100% correct for non-universal-input power supplies (those without an active PFC or voltage doubler switch).
The other problem with these is they typically tap off a small amount of the input voltage to “kick start” the oscillator; if there’s insufficient input voltage, the oscillator won’t ever start, or it may attempt to start, draw down the voltage further with the load, then shut off as if the over-current failsafe engaged. Then, after the capacitor charges back up, it’ll attempt to restart as before. It’ll then repeatedly cycle until you turn off the power switch, or unplug it from the mains. The worst-case scenario is that the oscillator doesn’t start, but leaks enough current to turn on the series-pass transistor (slowly) allowing the rectified DC to burn out the primary of the transformer; though this failure mode is dependent on the design, so it may not happen.
That was my thought too. Lower voltage equals higher current and things melt?
Hi Adrian, Berend here. Thanks for another great episode and happy we could contribute by donating this machine. Don’t feel bad about mispronouncing my name. Almost every American I met didn’t get it right the first time, so I am impressed you got it right at the end of the video.
Thanks for securing this laptop for Adrian. This was a fascinating video. Astounding how clean it was, too!
For all Americans: We are not German, we are Dutch! ( although I am Germen born.) We are still on 220 volts in Europe as far as I know...
@@richardheumann1887 Electrician here. :) 220V-240V actually. But 240V is more the standard now.
@@JakobF Not in the Netherlands it is not, as far as I can see. Maybe it is a spec thing and I just don't notice because everything says 220V?
@@richardheumann1887If you look at new stuff is should say 220-240V :) If you have the tools and the knowledge try to meassure yourself. But only if you know what you are doing, it´s a little dangerous.
'Velcro' is a portmanteau of two french words 'velours' (velvet) and 'crochet' (hook) named by the inventor.
1:02:06 "I don't think I'm gonna film that, because there's gonna be a lot of cursing..." Adrian, you are a gem! 😂
Holding the disk platter in hand ... "Well that escalated quickly"
I used a Toshiba 5100 back in the early/mid 90’s. It was a 386 but still had the orange plasma display. I worked for the railways in Sydney Australia and we wanted a PC for field work but the government procurement regulations at the time banned the purchase of laptops. To get around this problem, we got the supplier to sell us two units with bundled hardware modules and they listed them as protocol analysers. They were very capable machines in their day and were used a great deal by me and my team into the 2000’s.
I was given a T3100SX in the late 90s. 386, VGA, two chonking batteries with still 5 minutes of runtime (yes, plasma), great picture, but it died like 3 days later. Young me didn't know about that smell and leaking capacitors. Several years later I bought a T5100 on eBay for very cheap (like 5 bucks), unfortunately it has the same symptom as Adrian's Samsung, but a different cause - when it's cold and hasn't been used for weeks, it powers up without any bars at all, perfect picture, they start to appear after a couple of seconds and just get worse and worse until they settle after around an hour. It's still usable though. Just EGA though, but with a maximum resolution of 640x400 (which, I tried, my EGA monitor won't sync).
Why were they banned?
The thing I hate even more than the complexity of working on laptops, is the amount of plastic clips and thin plastic brackets that are often used. Over time the plastic becomes quite brittle because of the heat and age. I always end up breaking something, then have additional work to fix that. Thank you so much for this video Adrian.
The floppy issue is probably due to the original using the READY signalling on Pin 34 rather than the IBM-PC DSKCHG signalling. READY will go low when a disk is in the drive so the system wouldn't be able to tell that the floppy is in the drive so never try to read with the PC drive in there.
I remember the Toshiba (T3100) plasmas being much brighter than any of the early LCDs that were available, and it was waaaaay waaaaay better to type on. If you were using it for business, the plasma screen offered a way to type a document or something in a hotel room that was quite a reasonable experience. I do think they have dimmed over time
Hi Adrian, in The Netherlands we use the US International keyboard layout. There are keyboards with a Dutch layout, but we use it very rarely. I've seen it once in production 25 years ago.
I love the Adrian's Digital Basement QC Sticker. It gives me more guarantee and security to trust that floppy drive than if I had bought it new.
I love the long videos. 💚
Agreed, far too few YTers do long form video
Great video - it demonstrates that electronic repair on vintage equipment can sometimes be a challenge. I'm glad that plasma screens had a relatively short life-span.
Love seeing Dave's lovely multimeter. Forget the expensive Fluke, Dave's meters are amazing.
I know you said this was an unplanned deep repair… but this is the content I’ve been craving recently. I appreciate your commitment and followthrough. Thanks for all you do! I truly appreciate your information dense videos and soothing voice. I’ll totally be patronizing soon.
The Voltage in Europe wasn't changed, it was just the spec that changed to incorporate the Brits with their 240-240VAC. In my house the Voltage remains at 220VAC or 380V for 3 Phase. Yes, I measured it with my Multimeter.
Yep. And in the UK, even though the standard is now 230v, everywhere is still 240v as it's within the tolerance allowed.
Ukraine: 230V in newer city blocks, still 220V in older ones. When replacing old transformers due to failure or for more power, older blocks are switched to 230V as well.
The new distribution transformers installed all over Europe now are rated for 236V. Depending on the high voltage supply in the area they will have 230-240V output. Whenever high voltage distribution in an area is upgraded it gets closer to 240V for the low voltage. Higher voltage means less heat losses and higher capacity for heavy loads and more houses.
I just checked the Norwegian regulations which states that the voltage's "effective value" (I suppose that's Vrms) must be within ± 10% of the nominal averaged over 1 minute. The "nominal" is stated as 230 V in another section. There are a lot of other requirements too, of course, including a maximum asymmetry of ± 2 % (10 min.avg.) which I interpret as the difference from neutral/ground on each of the "live" pins. In Norway there's not really an N and an L wire to each socket, they are both "line" wires (L1, L2) at 115 Vac at a 180° phase difference. Correct me if I'm wrong, but I think this is quite common in Europe. (That's also why I think it's not technically correct to call it a 1-phase circuit, as many electricians seem to do; it's actually 2-phase.) The difference between N+L and L1+L2 in not something the devices will notice unless they specifically relate each phase to (protective) grounding 😉 They should be able to handle between 207 and 253 volts regardless, and as we see both an old 220V delivery as well as the 240V UK ones are still within spec.!
@@benhetland576 it's actually different in different parts of Norway. Some has 115V phase-ground/230V phase-phase as you describe. More recently built areas has the same system as rest of Europe which is 230/400V.
On the Yamaha chip, the Japanese text credits ASCII Corp. It's a different chip/part no, but the same credit is also found on the MSX custom chip that integrated a lot of the chipset logic together into one chip.
Couple of videos by Shelby over at Tech Tangents dive into floppy disk formats and how the media is laid out, which would explain why the 1.44 disks might not work in some of the 720 drives, which is partially due to how the signaling in them works I believe.
Most modern power supplies support multiple input voltages because they contain as first stage a power factor correction circuit that is implemented as a step-up converter and boosts the voltage to around 450 Volts internally regardless of the input voltage. Power factor correction is mandated by EU law for all consumer devices above 70 Wats. Since most consumer products are made to confirm to world-wide standards, they come with power factor correction and therefore support multiple input voltages as a freebee.
Quote of the week: "There's not much to report. It's beige." - I was howling with laughter
As a long term subscriber to VWestlife i have to point out: beige is the best status of vintage PC equipment!
Yeah, it sounds like the punch line to a Joan Rivers joke on a late night, Johnny Carson show😂😂!
Honestly that masking tape has probably held up better than most electrical tape would. The soldering looked pretty decent.
One can only imagine how long it has been like that. Honestly it may look 'jank' but at the end of the day how much can you criticize something that clearly worked and held up reasonably well?
In the 1990s the voltage in continental Europe was increased from 220V to 230V. England uses 240V, but at least 230V. A power supply for 220V also works well on 230V. In the US, 230V is also possible. Houses are often supplied with 115V split phase. That means between one phase and neutral it is 115V, between two phases it is 230V. 200-230V is used in the US for the cooktop and tumble dryer.
Technically, the thing that was first increased in 1983 was the nominal voltage. 230 V +/- 10% nominal, means that 220 (continent) and 240 (UK) are both in spec, plus all existing and new devices and nets are and will be in spec as well. That way the nets were able to be connected for power exchange, devices were able to be sold in both markets without issue, etc. Bear in mind that frequency deviation during power exchange /network interconnect is impossible to correct for without expensive HVDC systems, while these voltage differences are no issue. It took until 1987 till Germany moved to actual 230V on the grid. This thus further dates this machine. The UK is still on 240, with the "Isle of Man" famously being on 245 ;)
The U.K. nominal voltage is in fact 230v with a tolerance of +10/-6% (giving a range of 216.2v to 253v). This is stated in BS:EN50160. When the EU standardised on 230v, nothing really changed as the voltage tolerance is quite wide, allowing countries that were 220v and 240v to keep things pretty much the same.
@@der.Schtefan I generally get 245-250v on my very much mainland supply.
I am a bit surprised Adrian hasn't wired some 240V outlets on his bench without using a step-up transformer, perhaps his panel is full? Lower-current non-locking US 240V plug are a little weird with the sideways blade(s) but are not difficult to find at local hardware stores.
Us dutchies are used to using US International keyboard layouts. Usually using deadkeys to compose characters like é or ë etc. And we have a € symbol on the 5 key which can be typed with the "alt gr" (usually the right ALT) key. There is an actual Dutch keyboard layout which is also QWERTY but has the symbols moved around. I haven't seen those since typewriters and maybe old 8088 computers.
€ would not be on a vintage keyboard. I'm using Alt-0128 to this day 😉
My Dad had a Toshiba model similar to this one from around the same time period. It was a 286-10 I believe with the same CGA plasma screen, a 720K floppy drive, a 20MB RLL hard drive that was loud as all get out and the thing practically made the lights dim when you turned it on. He bought it second hand to use with his business, but didn't end up doing a lot with it. I used it with WordPerfect 5.1 for school stuff and also played a bunch of old Sierra games on it. I think I beat Space Quest 1 probably 15 times on it, to the point where if speedrunning was a thing then, I'd probably have been competitive with that game. The clarity on the screen was actually quite good, though it was only a few years old at the time so it was still in good shape and came with the bonus of being able to heat your entire room all by itself. I'd really love to find one of that Toshiba machine for nostalgia's sake, but finding one with a good screen is next to impossible and it would cost an absolute fortune to ship.
This is precisely why I appreciate the GRiDCASE 1500 series so damned much. They crammed top notch displays, into a portable form factor that could take a beating.
230V - 50Hz (used to be 220V too) also here in Greece single phase for homes but if you measure it you will see great fluctuasion from even under 190 to 250V which is really bad overall for electronics so a stabilizer is very useful especially under thunderstorms... We had a lot of Schneider PCs here and even if I respect Japan's products many times their companies design them in a really bad way for expandability-upgradeability and fill them with proprietary connectors and stuff which is really a shame and puts aside the great build quality of them. Great long video as always Adrian, keep up, JIm.
Poor Berend is "Bernard" now. =( Regarding key layout, the Netherlands uses QWERTY. They most use US layout for cost reasons though there is a Dutch keyboard with only a few tiny differences on punctuation keys.
I find it interesting that the Netherlands use QWERTY. Because I was in Belgium last week and what I've noticed is that they use the french AZERTY layout. I thought the Netherlands would use the same.
In Italy we use qwerty as well. The only difference from a us keyboard is in symbols and quotes
@@retropcs88In poland we had QWERTZ. With polish characters on side instead things like ! ? :
@@retropcs88Both French and Dutch are spoken in Belgium, and unfortunately the French with their stupid Azerty won. I personally use Qwerty being a Dutch speaking Belgian.
Well, for a time there was a real Dutch keyboard, which had a QWERTY layout but the () symbols shifted one place (key) over. That was the most annoying thing ever if you did a lot of programming. Fortunately it died out quickly.
Hi from Germany :-) Love your videos. Everytime i'm very impressed from your work.
Amazingly sharp transitions between the lit/unlit phases at around 10:00 when you're showing the screen rolling slowly; a gas plasma display like this could in theory be refreshed extremely quickly without resulting in any smearing or ghosting, based on that.
This "Laptop" is not from Germany, it's from Netherlands so keyboard layout is almost the same as UK layout
Very early SMPSU did have a possibility of damage under low voltages due to instability of the switching. Also at under voltage events it may trigger restart of the power supply. Usually the power supply for the power supply control circuit usually fails to start so not to cause damage on under voltage but once running low voltage can cause more damage due to higher loading. As far as I have found the units controlled with an SMPSU dedicated controller IC have no damage just the ones using discrete parts. Most modern PSU work from 100V(Japan) to 240V(UK now dropping to 230v) to keep life easy. I have popped a SMPSU drive transistor again using a Variac so now have power limiting on it & check the circuit diagram first.
Excellent job as usual and very informative. TY Adrian for all that you do for us!
wow for a quick description of how power moves through the power supply, that was kind of awesome!
Well hello Adrian. I suppose the extra FDD power cable mod was intended to be used with a replacement FDD to bring both 5V and 12V. The 720k might work fine with just the 5V whilst the other not so much
From my experience, I can't see how running the computer at the lower voltage would damage it. However, I can't imagine it working on the lower voltage. I have a lot of old solid state and tube type equipment, and when they haven't operated for some time, I use a variac, and run them starting at lower voltage, so that the electrolytic caps, have a chance to re-form. That way, I am able to get the machine operating, and then check to see if I have a potential problem, by looking for hot electrolytic caps. I have been doing that for over 30 years, and never experienced a problem. I enjoy your videos, they are highly instructive.
I am a new viewer to you're channel and I do like your enthusiastic, yet realistic approach to troubleshooting. It's funny because there is this kind of an "Art vs Commerce" paradox that you run into when taking on these projects, on one hand, you want to be detailed and concise on the other hand it has to be done within a time limit and one doesn't want to bore the viewer getting into theory, or spending too much time on uneventful yet necessary tasks. I will be tuning in from now on, Thanks.
I would wager in that generation of system/computer it might have required that before the computer was turned off to actually PARK the hard drive.
"Schneider Rundfunkwerke" (Rundfunkwerke: Broadcast Factories) - That is a pretty old name Schneider used back in the 80ties. Later after 1988, the Division of Schneider (that originaly build radios and radio cabinets) was renamed "Scheider Euro PC"
Picked up one of these Gas Plasma era portable beats this week - an STM5500. Can't wait to tear into it and get it all cleaned up. A portable with Canadian roots in my collection.
Adrian did *a lot* of work in this video, and it's unfortunate that any data couldn't be extracted from that MFM HDD, but it was *still* fascinating to see into the nuts and bolts of an example of the "laptop" technology that existed almost 40 years ago.
The problem with DD formatted HD disks is that the retained flux in the platter is lower than with true DD disks. That`s because the size of the nickel-iron oxide grains on the platter is greater in DD disks. So some of the DD reading heads don't get excited enough to read the data successfully. I had that problem often with my Atari ST machines and i think the cheaper drives have that problem. It can help to write the data with a DD floppy, because some are using higher magnetic flux than HD drives to write the data.
Absolutely true, but I've found that most drives don't seem to have a problem with it. I've gone in both directions (cutting holes in DD disks and taping over holes in HD media), and it works fine almost all of the time, at least with generic (non-IBM) PC drives and Mac/Sony floppy mechanisms.
I remember 400K macs (and maybe 800k?) had issues with taped over disks because the disk detect switch was in the exact spot that the high density hole was. So when you put a disk in, the computer wouldn't think a disk had been inserted and therefore would not eject it without using a papercliip.
The reason the 1.44MB fdd did not work in this machine is that it requires 12V as well as 5V, and that is prolly why that extra fdd power connector was bodged in.
There's also the matter of whether the FDC chip can even handle the higher data rate.
@@seancurtin6103 the BIOS supports 1.44 drives so it obviously should work. However if the battery fails the floppy gets set to 720 as default, so I suspect Adrian tried to boot from a 1.44 floppy...
What are you talking about? The reason why the 1.44MB Drive didn't work is b/c it is a 720KB Drive 😊
@@seancurtin6103 It can. Mine has a 1.44MB drive swapped in.
That was also my conclusion. Wonder why Adrian didn't notice :D
What a great documentation of the thing online.
Wizardry Proving Grounds of the Mad Overlord would look awesome on that red plasma display.
There´s something I wanted to ask you Adrian for some time, other than nostalgia and "honey!!!...Need a rag down here!!!!...throw me something!!", that 20yr old green-blue towel that you use, I used many of them when fixing things, speccially to re asseble already clean parts and is the best surface to work on, inspite the fact that they loose threads like a sheepdog. I love them!. So, is like that for you too
Adrian, Have you ever thought of picking up a set of those soldering tweezers? It’s a dedicated iron, that has two heated tweezer arms. That you can use for taking caps, resistors, fuses, and other components off, and on. I found they work for when you’re dealing with small components and need to use tweezers to hold things still, an iron, and maybe some solder braid/wick all at the same time and you King have two hands. Lmk your thoughts. Edit: To save you from some searching. Here’s a pair on eBay. Amazon also has some cheaper “smaller” ones that may work better for the small components. But for older electronics such as the ones you work on, these larger ones should do fine as everything back then was bigger. lol. 110V SMT IC SMD Hot Tweezers & Soldering Iron Desoldering ESD soldering station
Brilliant video as always! I have an old Roland workstation sampler that has a 720k drive. Over the years I’ve found some 1.44mb disks work when formatted with the tape over the whole and some don’t for some reason
Wow. Nice. I worked there . Grèetings from Bavaria Germany
I recognize the packing material. There are two chemicals in separate containers, and it's similar to the foam insulation stuff you buy to seal doors and windows, but it's intended for packing. I worked at a computer shop for a couple of weeks while taking a computer class in A+/CCNA, and they had these two large containers connected to an air compressor, and it would mix the two chemicals and spit out that foam which would then conform to whatever object you were packing (without damaging the packed material at all).
Oh yeah I've used the canned type for sealing cracks in a house. Didn't put two and two together it was the same stuff. I'm reusing the box and foam stuff to send something else to another KZheadr. Maybe it'll make a tour around the world :-)
@@adriansdigitalbasementIt's the same two chemicals with a thin layer of "oil" like a salad dressing in the can. You mixed the two chemicals in the can when you follow directions to agitate then apply. It's basically the exact same stuff only packaged differently. 0.05 to 0.075lb OC polyurethane. Edit The oil keeps the two components separate until you agitate. Ps you cannot "save the rest for later" as it will cure in the can into a dead lump.
"Nova Foam" is one brand. It's basically the same as the canned "Window Foam" "Great Stuff" etc. Generally known as "bag foam" in the industry "Packing Foam".
I also used the spay sealing foam. I sealed my back door with it some years ago. That old house was from the '50s so it was poorly insulated and the wiring was questionable in many places. Never realised you can't "save the rest" for later. Good to know.
@@jandjrandr The drums last 6 months from fresh on average. If left sealed the MDI can sit up to 5 years but the Poly- 6 months if it's a budget brand and 3 years if it's a premium brand but the manual will state 6 months from date of manufacture. OC is 6 months then spoils into waste. CC gradually becoming heavier and harder to work but can be revived even when old. The cheapest hardware store rattle cans are what I was talking about. Once it's shook up you already have your uses ready for application and toss the remaining balance or give to a neighbour if he has a quick use. It goes hard inside the can in a few days.
Reminds me of reviving some much later Compaq SLT models from late 1988 that I recovered in like 98-99. I wish I only had the means back then to transport and store some of the pallets of vintage gems that were just getting tossed in dumpsters year after year.
Hi Adrian! It looks like the laptop has straight floppy cable. Your 1.44Mb floppy drive is most likely expecting the cable to have a twist. Like you self said on the video - the twist takes care of the drive select. You might get the 1.44 Mb drive to work if you try it with twisted floppy cable. if your 1.44Mb drive mechanics spindle did spin, but led did not get on, you might also try a poor mans job: the DS0 signal comes in wire 14. Cut wire 14 and connect it to gnd on the drive mechanics end (say pin 13 for example). Leave the laptop wire no 14 unconnected. This will result the drive mechanics to be constantly selected. The led is constantly on, but the drive should work normally. Not elegant, but practical to at least test if it works.
i had a Schneider/Amstrad PC1512 in the past. seeing an 286 laptop from them seems like a novelty to me. But i like the idea of restoring it!
That's a beautiful machine
My 1st Computer was a Schneider CPC 6128. Schneider used to build/distribute Amstrad Computers for German speaking Countries. At some point Amstrad/Schneider parted and Schneider made some of their own PC Creations. My 2nd Computer was a Schneider EuroPC. I could bite my a$$ for not keeping it 😢 This 7640 one was still licensed from another Manufacturer before Schneider came out with their own "Euro PC / AT" Series, which then also had non-US Style Keyboards. FunFact: The EuroPC was CGA and HercMono, depending on Bios Setup+Monitor.
One of the greatest mysteries as a kid was "what the hell is a Schneider?"! It was always on the back of Amstrad games, but we had no idea what it was! Nowadays you'd just Google it, but back then we no clue!
Is this the same company as Schneider Electric who own APC?
@@wesley00042 No, the Schneider you are referring to is french multi-national, while the computer Schneider from this video is actually german.
Schneider Rundfunkwerke doesn't exist anymore.
When Adrian goes gun shopping he prefers the Phased plasma rifle in a 40 watt range.
Hey, just what you see pal...😁
You can't do that! Wrong.
Joke aside, I see him as a pre-1700 black powder "retro" guy.
I think the clock chip is the OKI 16 pin DIP between the 32kHz crystal and the camera. The NiCds running those chips were almost always charged through a small signal diode and a resistor (often 470Ω) to +5 which is easy to Ohm out from the battery plus lead. I wouldn't be surprised if that resistor was R62 and the diode was D1, with D2 providing Vcc to the OKI clock chip during normal operation.. Just clip the resistor and/or diode out and you're safe to use a CR2032 without any protection diode which will reduce the useable life of the battery by quite a bit due to Vf.
There are ML2032 batteries that are Li-ion, but have the form-factor ef CR2032. ML2032 of course have the nominal Li-ion voltages, meaning 3.6V or 3.7V nominally instead of 3.0V, and 4.2V fully charged. They can be used in place of your 3.6V NiCd however. I use them all the time both for projects like these as well as CR2032-powered devices such as candlelights that don't care so much. Even my 300€ Tesla key fob seemed to work initially with it, but then fried. The Sega Dreamcast used these originally, but I don't know of any other product that did so, and even there they were welded with tabs that were soldered, so I replaced that with a CR2032 holder on my Dreamcast..
Logitech had a solar powered keyboard with an ml2032 in it.
Working as a 'counter person' at a classic electronics store in the mid-80's, YUASA was our main (sealed, lead acid) battery vendor. At first I thought that name sounded so familiar and then like a jealous GF, it finally hit me. I use to sell them. Unfamiliar with the Nickle Cadmium ones though.. Thanks for the flash back
A quick note on that FDD with the resistor for the drive select; that's a Zero-Ohm link so you can replace it with just a solder bridge blob, though you are forgiven knowing that you sometimes struggle with seeing small things like that, even I'm starting to have trouble reading resistor numbers like that given I'm approaching 40 and the eyes are getting worse for close-up stuff... :)
When you started saying the company name Oki Data, I wondered why it sounded so familiar. I went looking and realized the printer I have my for my Commodore 64 is an Oki Data brand. 😄
Oh yeah, OKI had a small color ribbon printer for the C64, I went with the Commodore dot matrix MPS-801 grinding away slowly one line at a time. hehe Also, in the early 90's I had a Toshiba laptop (it was huge) with a plasma screen, it was incredible back then. :D
I think my dad bought something like this back in the 90'es. It was a second hand purchase that he never got much use out of. I remember it was a pretty heavy laptop (too big and heavy for the lap) and it had a red screen. Unfortunately it was very dim even back then, so it was a strain for the eyes to use it in bright daylight.
I own a Toshiba T5200/100 with a working plasma display, and it's my favorite weird DOS gaming platform. It's not blazing fast, but it does have a 33 MHz 386DX with the 387 math coprocessor installed, which is enough for Wolf3D. It's also got a 100MB IDE hard drive, and 4 MB of RAM that can be set in BIOS to be either extended or expanded RAM. The panel is 640x480, and it supports all the CGA/EGA/VGA resolutions & color depths. (emulated through monochrome, obviously.) It also has a VGA out that mirrors the onboard panel. It doesn't have PS/2 ports; it's a few years too old for that. But it does have a serial port for a mouse, and some kind of proprietary port for an external keyboard. But what's best about it is that it has two full-size ISA slots; one 8-bit and one 16-bit. I put a Sound Blaster 16 in one and an XTIDE in the other, which really works out well. It's a fun little oddball of a machine.
Lots of great linguistic gems in this episode. I wonder if the plasma controls are behind the bezel or trim pots on the board? My dad had an Osborne portable computer. That thing was a beast.
I know this is not much related, but I want to share this so everyone can have a laugh... :P For the longest time (YEARS), I wondered why the hell floppy disks had CH written on them.
I'm surprised someone hasn't made a RP2040 based MFM adaptor. I've used them to build my own C128 board entirely (basically an emulator to be fair, but different microcontrollers handle different category/sections of execution and communicate together and with other chips like memory, the entire reason I built it was to mess around with having a few working together). As slow as those drives were relatively speaking in reading/writing data, it shouldn't be out of the realm of possibilities for a bulk of basically everything to be handled by a pico/pico based microcontroller.
MFM on a HD floppy requires around a 80+MHz processor to function properly in software emulation of MFM, a harddrive spins much faster I think, around 5400 or 7200rpm compared to 300rpm for floppies? Not sure the pico could handle that. The pico does have some programmable logic and dma so that might make it possible to pull off but you'll probably need an fpga. But with everything it takes time and effort and someone has to take an interest in it to invest it.
@@imqqmi I think MFM drives are 3600rpm. And the Pico has a dual-core 125MHz (with massive overclocks possible) which is quite fast. It should definitely be fast enough for dumb emulation of a single track in RAM. Then when the PC commands a seek it needs to write the modified data back to nonvolatile storage and prepare the next one. I don't know how the standard MFM interface handles seek timing. If the interface has a "seek complete" signal the Pico could take as much processing time as it needs.
@@eDoc2020Let me put it this way, a gotek drive has a 150MHz part in it, you'd go from 300 to 3600rpm so more than 10x as quickly, you'd need an mcu of 1.5GHz to keep up. Dumb single track emulation is one thing, storing writes to a bytes encoded disk image on sd card or usb stick is a whole 'nother can o worms 😉 A one track hdd is pretty useless. You could store the raw flux transitions but that would increase storage size and data throughput 10x. That makes it difficult to get the data out to storage in time for the next track. You'd be looking at 200KB in 16ms or 12.5MB/s. You'll quickly run into write access times of sd cards and if the spi interface supports quad spi etc. A Teensy 4 overclocked might just pull it off but you'd probably be better off with a recent pi zero that can buffer an entire mfm disk in memory.
I had a similar vintage orange plasma screened laptop in the early 90s. It was a hand me down. I don't remember the screen being particularly dim. In fact I remember it being pretty vibrant. I did a lot of homework on that machine using a word processor named KenWriter and printing to an old Epson RX-80 I was still rocking from my C64. I also did my programming work on there for tech college. I remember writing Cobol code and jcl to get it running when I took it to the mainframe. I even gamed on it and dialed in to BBS' in the evening. Neat machines, I kind of wish I still had it.
7:08 love squetch cheap chinesium plastic adapters
My stepfather was working in Germany for a year around 1987-88. When he came back to my mum in the UK he came back with a Schneider desktop with a CRT. I assume it was from this generation. He had DOS and x86 CP/M which he preferred.
Great video
This was cool. A classic Adrian long video!
Wonderful people like Peter and Berend in the world. Excellent.
hello adrian...my first moods have "PanzerTape" as Isolation...i`n not proud of this work! 🙂thanks for upload and a nice eatern`24 all fans from the old technik!! 🙂...your RoboTronic64 from chemnitz/germany...
Larger homes in sweden have 3 phase 400V 16A connections for stoves, washingmachines and larger electric tools. This is split in to 240V at 16A, 10A or 6A lines for lighting and small appliances.
I've got an old 286 laptop like that with a dead or stuck hard drive... it's in my "some day" pile because I dread taking it apart for exactly this reason!
6:58 DeathDaptor™ Never leave home without one! 8:00 Hmm, it's some odd variant of a UK layout because the left shift is wide, rather than narrow and with the pipe/backslash key to the left of the Z. 49:30 That went from "hospital bed" to "morgue" really quick!
Yes, feeding a 220V ONLY PSU with only 110V can damage it. Because half the voltage -> Double the current. And the components inside might not be made for that and blow up. For older PSU like this uses, they use a special pump circuit for boosting the Voltage called a Voltage doubler. For that you need to replace the diodes with stronger ones or the Bridge Rectifier, possibly replac the Caps with more capacitance ones. Active PFC ones in modern PSU have a boost stage anyway, those can't be converted and would blow up. That is the case for most modern Consoles for example XBOX One, PS3-5 and so on. Because its just a buck or two cheaper to not make them universal voltage.
I used a Compaq luggable with a similar orange plasma screen back in the day. To my memory that panel was indeed slightly brighter and perhaps with a somewhat sharper rendering. That Schneider is a nice relic - it would be quite acceptable with a SSD in it (assuming that's possible with some magic adapters) running Turbo Pascal and such ;-)
1993-96 at university, I had a 2nd hand down IBM PS/2 P70 luggable (a gaming buddy worked at a big IT company and they were getting rid of them at the time, going to actual laptops so I paid about £300 for it which as a mature student was just about affordable). It was quite the beast, Gas plasma screen, 386dx cpu, 8mb ram, 120mb hard disk, Microchannel Sound Blaster, my mate made sure it got specced out to the max from his companies parts bin. Doing essays and coursework however, it was a sweet machine indeed, playing Doom however... that was a challenge (is that water or lava I need to run across? they looked the same, only one way to find out!). Sold it on when I graduated to another student who got a few more years very good use out of it.
Adrian, If you grab an extension cord from one outlet, and another one from a different outlet, and you sit them side-by-side, so the two "line" slots are facing each other, you can get 220V. I do this with a pin-changing travel adapter, for use with euro appliances, no step-transformer needed!
If this doesn't work, you need to try a different outlet for your second extension. Usually it's in another room.
If I understand US voltages and wiring correctly, that is the same as connecting it to the two "hot" slots on a 240V dryer outlet - is it? The device might work fine on its own - but - what happens when you add a ground connection or connect up something that is wired to an actual neutral via a shielded cable or something ... like ... if you plug a US monitor connected to a normal 120v outlet into your EU computer that is running off the two hots of a dryer plug ... what would happen ???
You get two hots when you do that. The power switch may not switch the neutral line that is now hot and it won't have a fuse either.
@@KenjiUmino Nothing would happen, because, the transformers present in both devices, would prevent a direct connection to ground, from any line source, and, ground would still be ground. As it is, in an electric clothes dryer.
@@KenjiUmino It is essentially the same as a dryer plug. If you connect two things that are _truly_ connected to neutral you'll have problems. But such connections are never present on user-accessible connections because it would be a massive shock risk. Usually the device's circuitry is isolated from the power line by a power transformer, in a few cases the internal circuitry is not isolated but the signals go through a transformer or other isolator.
If you like the orange gas plasma screen I would really recommend reading the book "Your friendly orange glow" ..... while the story of the development of the gas plasma screen is in there it also explains why is it orange and why even to develop it.....but it is really a book about a forgotten part of the history of comuting. It tells about a system called PLATO developed on main frame computer at the Illinois with a purpose of being used for teaching.....which eventually was composed of thousands of terminal connected to it and becoming way more than just a teaching tool but some sort of an early internet like system where many of the things which we think were invented as part of the internet like chats, online message boards, online news papers, online gaming with multiplayer and many more things were basiclly re-discovered when the internet happened
Wow! The moulding looks almost exactly like a Toshiba T3100. But the Toshiba gas plasma laptops were charcoal gray. I recently sold one of these to another collector on Facebook along with a T3100SX. Im guessing like many companies were reselling different models of Toshiba laptops.
That's a freaking gorgeous machine. I'm looking into acquiring a Tandy 1400HD or an IBM PC Convertible.
Tripped out video, Adrian. Thanks! Do you ever watch Sorin (Electronics Repair School)? He's a great tech, too.
There seems to be a few similar-but-different machines built by the same OEM out of Japan. I have another variant, the Ai-PC16 sold by Ai Electronics Corp. in Tokyo, but probably also manufactured by Oki. I believe it was an imported unit, originally sold in either Australia or New Zealand, because it has a factory-fitted 100-220V AC 50/60Hz power supply. The machine has a date code of "8901", presumably Week 1, 1989. The case and internal chassis is very similar, but the rear layout is inverted - the expansion slot and power connector is to the right of the IO ports. Mine also has the cutouts in the case on the opposite side from the Floppy Drive to install a second drive, but it has a 3.5" blanking plate installed with a 40MB NEC MFM drive fitted behind it. Mine also shipped with a 1.44MB floppy drive as standard. The bodged Floppy power is probably an aftermarket modification. Mine doesn't have a Berg connector coming from the power supply, instead the Floppy cable from the motherboard carries power, and two wires are broken off from the ribbon cable to a Berg connector. Only the 5v and GND wires are connected, no 12v. A couple of quirks I noticed with mine that may also apply to the Schneider - when the battery dies or the CMOS is reset via another means, the BIOS defaults to running the Floppy drive in 720k mode. If I boot from a 720k disk, reconfigure the BIOS and reboot the machine, I can then boot from a 1.44mb disk. If for any reason the CMOS becomes corrupted and the machine just hangs on boot, I've been able to skip the long wait by removing the battery and grounding out the positive terminal of the holder (with the machine unplugged), which seems to discharge whatever circuit is still somewhat powered and resets the CMOS back to defaults. Although most variants I've managed to track down seem to use the 1.29E version InterLINK Business Network Corp BIOS (I think I've seen one exception running 1.30), the SETUP utilities differ between models. The Ai / Rein compatible setup utility doesn't work on a Schneider and vice versa. Your video likely answered the question of why this would be the case - different versions or revisions of the motherboard. Overall these aren't particularly useful machines, but it's still one of my favourites. It serves mostly as a dumb terminal, connecting to bulletin boards and other services through a null modem cable to another machine running TCPSER, and the plasma display makes it look very cool while it's doing it.
Switching PSUs are usually quite tolerant of moderately lower voltages and most modern designs are like 90-250V universal input, but this is old stuff and the label was explicitly 220V, so I would not risk using anything lower than 200 V.
Formatting a 1.44 disk as 720 will often result in a disk that doesn't read after a certain amount of time due to differences in the magnetic coercivity of the magnetic media.
That's not the only problem If you take a previously 1.44M formatted disk, format it in 1.44M drive, you now have a 1.44M disk with every second track containing a garbage data. It will read and write in 1.44M drive in 720k mode just fine because it is only reading every second track. The issue arises when you try to read it in 720k drive. That one picks up both actual track and garbage tracks around it, so it reads garbage. What's worse is that when it writes data even if it can erase stronger magnetic flux of the center track, it cannot quite overwrite the garbage written on the fringe tracks. That's not all though. If you have a 720k disk you can read it in 1.44M drive just fine. But if you write it in 1.44M drive you can not no longer read it reliably in 720k because now the 720k head left the ghost flux residue between the narrow 1.44M tracks, which is the portion 1.44M drive have overwritten. Actually it may not even read reliably in 1.44M drive anymore. Overwriting such a disk completely in 720k drive - possibly several times - might help - granted it was never ever formatted as 720k, never as 1.44M. So if a disk was ever formatted as 1.44 (which they are from the factory) you can never use it in 720k drive reliably. If you have a 720k disk that was never formatted in 1.44M drive you may read it in 1.44M drive but if you ever write it in such a drive it won't read in 720k drive until you format it in 720k drive again. A 1.44-"infected" disk can be restored only with a magnetic flux eraser aka demagnetizer and then formatting it in 720k drive. Simply overwriting it in either drive won't restore it to work with 720k drives. This is why having a 720k drive - and using only it for 720k disks - is essential if you are doing retrocomputing stuff. Another option is installing 1.44M drive into 720k machine. It will be able to read and write disks formatted as 720k in 1.44M drives, and 1.44M drives will be able to read such disks. Any disks it writes will be in 720k-but-actually-1.44M-track-width format, interchangable only with 1.44M drives. It will also read normal 720k disks but you need to clearly label it to not write true 720k disks in such a machine.
@@jwhite5008 I used to tape over bad floppies (usually with a track 0 error) and try to format in 720K. This usually resulted in a usable floppy with a smaller capacity. I also discovered that this action sometimes would make the floppy format back to 1,44MB (after removing the tape of course) and 'fix' the floppy. I'm not sure about the how and why, but hey, it worked for me :)
@@dustinslaboratory897I'm not really sure what happened with your disks but it could actually have been an alignment problem with the drive. I don't think formatting a disk to a different density helps to move the track-0 from the damaged cylinder to a less damaged one but I may be mistaken.
@@jwhite5008 I am glad someone pointed this out. Back in 92 I had an Amstrad PC1512 with 5.25 floppies. College had 386s with 3.5 HD drives, To get work home and back I used a friend's 286 AT which had a 1.44 and a 1.2 drive, Never had a problem but had to be careful about overwriting disks,
@@jwhite5008 Could be, I'm not sure what was going on, but it worked for me. I didn't notice anything particular about my other disks or drive. Things just worked usually, and if things went wrong, I just formatted them to 720K. Haven't tried this in over 30 years, so yeah, not sure if this is a thing. I used Nformat for this, i do remember that;
I had issues with a HD disk as 720, but got it to work by forcing a format of the disk. After that, it worked fine.
Schneider PC 7640 aka Schneider Euro PC, their 1st product when their partnership with Amstrad ended in 1987. Owned now by TCL.
The Schneider Euro PC is a completely different machine. It's an 8088 based "keyboard computer", with the system integrated into the keyboard, styled much like the Commodore 65.
My Tandy 1100FD always had problems with 1.44MB floppies formatted to 720K.
I believe 3.5" disk hole sensors are optical, so whatever tape that covers them must be opaque.
I used to use round coloured stickers on HD ones in my Amiga.
I've used clear tape on HD diskettes in the first Sony OA 3.5" floppy drives with success. Occasionally there are read/write issues probably due to the differences in the magnetic media.
I used a paper puncher to make ED disks from HD. This plus using arj to compress data was a great way to lose all data.
It varies. I've seen drives with optical sensors and I've seen drives with mechanical sensors. But you're absolutely right that clear tape won't work if the drive's sensor is optical
1:13:15 When you swapped the disks, the volume serial number was changed to the correct value, so at least that much is working.
undervolting can really damage PSUs, i have done this with a variac "just for fun" in die early 2000.. when nobody wanted XT aera machines and we rought them to the landfill... just for the fun of generating a lot of pixie smoke...
About the power supply, just change the plug to use the 240 V receptacle you use for the air conditioner. Or add a 240 V receptacle, with all that electrical stuff you must have a 240 V circuit somewhere around the place.
It's not easy to find an open 240 recepticle in the average US house. Most have 2, one for electric dryer and one for the electric range. Most older garages don't have an outlet unless one was added for a welder or electric car.
Hi Adrian, The floppy drive that came with the computer used 5 volt only it's spindle and head stepper are rated for a 5 volt operation that is probably that other berg connector was there someone used a 1.44 in there with it for a while.
The "NL" in the serial number was definitely about the keyboard layout, NL uses either standard US or there was an older "Dutch" keyboard layout with only the symbols arranged differently. Germany used QWERTZ keyboards where the French-speaking countries opted for AZERTY. So the machine was adapted for the Dutch market.
Hi Adrian. I wonder if there’s a newer (and smaller) version of the MFM emulator nowadays? One that has one or 2 GALs (or an FPGA) instead of the glue logic chips on the one you have. Then, maybe it would fit. 😊
The old Dutch keyboard layout was a QWERTY ANSI layout. That keyboard with the large enter key is somewhere between the ANSI and ISO layout, missing the key to the left of "z" for ISO, so despite being UK-ISO, its not quite. The Dutch layout is almost extinct these days apparently, with most companies either using US ANSI or US INTL ISO layouts.
I don't advocate using masking tape for electrical tape, but have I done it before, absolutely. And painters tape works really well !!
For the disks, it depends what drive you use to format it: if you format a disk with 1.44 drive using 720Ko format standard, you'll find 720Ko which won't read it. Same with HD/DD 5"1/4 drives.