Re: The 286 Laptop Restoration Thread

Posted on 2024-01-04, 18:51

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Those PWM signals look normal to me. The blinking LED when trying to re-power the board is something I encountered as well. You have to wait for the 5V_B rail to drop below TTL logic high (around 2V) but preferably 0V. Makes testing and debugging a bit tedious as the capacitance on that rail means …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-12-16, 10:39

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

My PSUs don't make any sound when running. At least nothing I'm able to hear which is generally anything below ~18KHz. When the board is first switched on there is a bit of sound from the inductors physically deforming a bit under the magnetic field, I guess that could qualify as a "clicking sound". …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-12-13, 18:30

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Had to have a bit of a think about this. The behaviour you're seeing with the 5VA and 5VB bus makes sense. I had to wait a couple of seconds after 5VB went off before attempting another powerup. A clicking sound would suggest that a capacitor or inductor is shorting, the PCB should be completely …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-12-10, 16:07

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Batteries are not required for the T1600 PSU board to operate. The rest of the computer isn't even required, it will work stand-alone (i.e. only connected to the 12V DC brick). Is there no PWM on the MOSFET gates at all? If it attempts to start but fails to reach the proper voltages in time there …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-08-08, 16:01

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Could be a number of things, really. What springs to mind: Dodgy capacitors on the LCD module Cold (cracked) solder joints Bad contact on the LCD zebra strip (I don't know if this LCD has those and I'm not sure that wpuld cause this type of fault) Bad LCD driver ICs on the LCD module Bad video cable …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-06-27, 17:20

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's good to hear, glad the T1600 schematic helped. It's unfortunately not uncommon for more parts (like diodes and the comparator) to fail as people try to power the machine up without replacing the caps. It can cause some pretty large voltage spikes when they're not doing their job correctly and …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-06-19, 17:57

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The controller can't sense current draw directly, it doesn't have the circuitry to do that. A possibility is that one of the rails gets loaded down a lot which causes the voltage to not reach the appropriate level in time causing the controller to shut things down. A 4-channel scope is handy in …

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Re: The 286 Laptop Restoration Thread

Posted on 2023-06-16, 20:26

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The first T1000XE wasn't that hard to fix, replacing a couple of capacitors and some minor PCB repair did the trick. I started work on the second machine I got but haven't got around to finishing it, real life kind of got in the way. I did start work on a T1000 which confirmed my thoughts on all the …

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Re: Toshiba 220CS doesn't get past BIOS

Posted on 2022-04-20, 06:11

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

All of my pentium-class Toshiba laptops still have their original thermal pads, as long as they're still soft and making contact to all thermal surfaces you're good to go. If your machine has a fan I would test that on a bench powersupply, just to make sure it can turn on when needed but other than …

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Re: Identify capacitor type

Posted on 2022-01-28, 10:34

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That through hole MLCC looks exactly like the thing I'm looking for. Thanks a bunch, I was really scratching my head on this one. So many different technologies to choose from.

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Identify capacitor type

Posted on 2022-01-28, 08:02

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm struggling to identify the type of the capacitor in the picture below. It's a 47nF bypass/decoupling cap from an IBM 6181682 Floppy controller so I could just use a generic ceramic. I would like to keep it looking OEM as much as possible though. It looks like a film capacitor to me but what …

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Re: Is it possible/safe to connect multiple PS/2 keyboards to one PS/2 port?

Posted on 2022-01-11, 08:28

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This might be a good place to start: http://www.burtonsys.com/PS2_keyboard_and_mouse_mini-DIN-6_connector_pinouts.html Especially the second cable pinout is of interest as it seems to suggest that simply connecting the keyboards in parallel should work, though I can't see how when looking at the PS …

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Re: The 286 Laptop Restoration Thread

Posted on 2021-08-06, 18:34

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That list of steps to take looks pretty complete to me. Part of the problem why the "add new solder" trick doesn't work is because the old solder is corroded by the electrolyte from the capacitors. I find that scratching a bit of the corroded material off to expose some shiny solder and adding lots …

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Re: The 286 Laptop Restoration Thread

Posted on 2021-08-05, 19:12

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It's great to see others making progress repairing their T1600's, it would be a real shame to see these cool and quite innovative machines end up being scrapped. To be honest, I'd like to salvage all old 8086 through 80386 Toshiba laptops I can get my hands on but then space is becomes an isssue. I …

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Re: The 286 Laptop Restoration Thread

Posted on 2021-03-16, 09:43

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, you don't _really_ need an oscilloscope but it does make it a lot easier. You can desolder all through-hole transistors/MOSFETs and test them but that can be a bit of a pain, especially when the solder is corroded. You can test the diodes using a multimeter, that should give a pretty good …

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Re: The 286 Laptop Restoration Thread

Posted on 2021-02-02, 07:19

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you very much! The PCBs cleaned up nicely with minimal effort, though the PSU board did require a couple of wash cycles with vinegar and alcohol unfortunately removing any stamps and the serial number sticker. The rust on the RF shield was a different story, the plastic is moulded onto the …

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Re: The 286 Laptop Restoration Thread

Posted on 2021-01-29, 16:01

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The first video is finally up, they will be released every friday at 4:00 PM CET. They can be found on my YouTube channel, the first video can be found here: https://www.youtube.com/watch?v=K_-vP0P0AxU&t=51s

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Re: The 286 Laptop Restoration Thread

Posted on 2021-01-04, 19:23

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, I be damned. The JVC drive actually works flawlessly. The BIOS seems to be overridden by the JVC controller. As I have removed the CMOS battery (it was dead and slightly leaky) and the system asks for a harddrive type when powering on. It then lets you choose from 3 different drive types, two …

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Re: The 286 Laptop Restoration Thread

Posted on 2020-12-23, 13:17

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by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It might be a standard also used by Fujitsu, though the signals will probably be different. The JVC drive uses what is basically an ST-412 interface but without the twisted pair: https://knm.org.uk/blog/2017/04/the-jvc-26-pin-hard-disk-interface-part-1/ A quick Google search on the Fujitsu doesn't …

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Re: The 286 Laptop Restoration Thread

Posted on 2020-12-23, 06:34

by

by FuST

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank you very much! First let me answer your question. This will be a bit lengthy as I'll explain what I found wrong with my boards. The most common components are obviously the capacitors. This is, as you probably already know, a problem for all Toshiba laptops from the late 80's/early 90's. My …

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