Author Topic: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL  (Read 9363 times)

0 Members and 1 Guest are viewing this topic.

Offline EEVblogTopic starter

  • Administrator
  • *****
  • Posts: 37934
  • Country: au
    • EEVblog
EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« on: February 02, 2023, 11:22:31 pm »
his Ebay Toshiba T1000LE vintage DOS In ROM laptop repair turned out looking promising until, well, it didn't...

Service manual: https://www.minuszerodegrees.net/manuals/Toshiba/Other/Toshiba%20T1000LE%20-%20Maintenance%20Manual.pdf

 
The following users thanked this post: SeanB

Offline .RC.

  • Frequent Contributor
  • **
  • Posts: 268
  • Country: au
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #1 on: February 03, 2023, 10:44:33 am »
I take it is just a rebadged Cyberdyne product?    :D
 

Offline thm_w

  • Super Contributor
  • ***
  • Posts: 6575
  • Country: ca
  • Non-expert
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #2 on: February 04, 2023, 07:31:23 am »
As mentioned in the comments some parts are blown, C520, then another tantalum? cap under R513. If the rail was going overvoltage would make sense why they blew (the 7V you saw).
Might be worth clean and replace those, but, if those logic ICs were damaged from the same overvoltage then may not be worth it.

Soldering leaked electrolyte smells horrible, cat piss level of stench. Possible hot soapy water might be a better initial cleaner here:
https://www.eevblog.com/forum/beginners/what-chemical-to-clean-the-pcb-after-leaking-capacitors/
« Last Edit: February 04, 2023, 07:34:31 am by thm_w »
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 
The following users thanked this post: EEVblog

Offline EEVblogTopic starter

  • Administrator
  • *****
  • Posts: 37934
  • Country: au
    • EEVblog
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #3 on: February 04, 2023, 08:54:15 am »
As mentioned in the comments some parts are blown, C520, then another tantalum? cap under R513. If the rail was going overvoltage would make sense why they blew (the 7V you saw).
Might be worth clean and replace those, but, if those logic ICs were damaged from the same overvoltage then may not be worth it.

Yeah, there is a non-zero chance of going to all the effort of cleaning it, and repairing all the traces and failed components only to find that a bunch of chips are fried.
Best bet would be the find a way to bypass on the PSU and feed in an external supply. Unfortunately no schematic is available, and I don't have a good unit to compare to.
 
The following users thanked this post: thm_w

Offline c64

  • Frequent Contributor
  • **
  • Posts: 300
  • Country: au
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #4 on: February 04, 2023, 11:34:50 pm »
I have the same model, also not working. Didn't see any broken traces though.

Half of the paint from the lid was already missing, so I just peeled it all off. Now I have silver lid  :D - but surface is not perfect.

Why would you buy it from 'merica? They are not super rare here. For example this one sold for $125 just last month
https://www.ebay.com.au/itm/Toshiba-T1200-Laptop-Model-PA7048EA-Good-Condtion-Parts-or-Repair-/325476605763
 

Offline EEVblogTopic starter

  • Administrator
  • *****
  • Posts: 37934
  • Country: au
    • EEVblog
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #5 on: February 05, 2023, 09:53:42 am »
Why would you buy it from 'merica? They are not super rare here. For example this one sold for $125 just last month
https://www.ebay.com.au/itm/Toshiba-T1200-Laptop-Model-PA7048EA-Good-Condtion-Parts-or-Repair-/325476605763

That's not the DOS in ROM version.
 

Offline vasonline

  • Contributor
  • Posts: 23
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #6 on: February 05, 2023, 10:46:31 am »
Hi Dave,

I have the same T1000LE repaired during the Covid time.
At one point I had abandonned the project, but I went trough.

Some things I learned from that experience:
(you might already know some of them? - I saw some mis-information in one of the YT comments)

- You do not need the battery installed to power the laptop.
- You _do_ need the hard disk installed. There is a switch on the MB/HDD that will press in when installed. Laptop wil turn on and will shut off w/o HDD. Very confusing!
- There is a small nicad for RTC. Behind the insulating tape, it was leaking - removed
- The power brick is not a problem at all.
- Screwing out and pressing in the last screw is easier for lifting the keyboard. (had trouble with that too)
- The LED board with the charger/battery is not the problem (Caps were good there on mine too)
- If Q504 blew, you will have trouble getting the DC IN light staying on. So that's good.
- My laptop blew Q504 and C524: I believe this was caused by myself, by the initial powering on. (not knowing what had happend inside to the power supply capacitors.)
- Between T9041 and C524 (that blew) I had a broken trace - repaired.
- The logic chips were not damaged by the overvoltage that blew C524
- Went over the whole thing with vinegar, toothbrush and IPA.

Afterwards;
- I haven't seen much of the DOS in rom, mine boots straight off the HDD. I'm not sure it has that feature. (fine for me).
- I had to open the keyboard, because the corrosive atmosphere had corroded some traces (fix with conductive paint) or maybe someone spilled liquid in there?
- You need the change the floppy belt.
- Battery charger works, as an experiment, I charged up six NiMh cells with it, and it would run on that just fine.


With new caps, broken trace repaired, new Q504 and C524 my T1000LE works.

I attemped to draw a (sort of) schematic of the PSU (very incomplete)

I'll post it here, maybe it is helpful?

pic of floppy drive
pic of how to open battery pack w/o destruction.
pic of completed t1000le
pic of schematic

also check out this site (not mine):
https://thomwijtenburg.nl/2020/06/19/t1000le-psu-the-finale-hopefully/


Greetings & good luck!
« Last Edit: February 05, 2023, 11:24:51 am by vasonline »
 
The following users thanked this post: EEVblog, thm_w, c64

Offline Ranayna

  • Frequent Contributor
  • **
  • Posts: 878
  • Country: de
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #7 on: February 05, 2023, 12:02:39 pm »
Oh wow.
From the outside, that notebook looked to be in an excellent condition. That must be really close to the original coloring.
A shame that it is a mess on the inside.
 

Offline psychoacoustic

  • Newbie
  • Posts: 4
  • Country: de
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #8 on: February 06, 2023, 06:53:38 pm »
Watching this episode made me think I should examine the Epson PX-4 I have lying in the attic and recap it. Even though it still works fine (even the Cassette which acts like a floppy drive), I don't want those caps to spill their guts and corrode the board. I open it up and...

They all look pristine. Nearly 40 years old (I saw datecodes of 1985 on the chips) but the board looks beautiful. I'd do more damage desoldering and removing the caps as long as I keep monitoring I figure.

Now I don't have a LCR meter so I can't check if they are still reasonably close to their nominal values, but I think that'll be my next investment. Maybe I can catch degraded ones before they become an issue.

...now if only I could get a QWERTY keyboard for it (it's got a German QWERTZ)...
 
The following users thanked this post: EEVblog

Offline TimFox

  • Super Contributor
  • ***
  • Posts: 8018
  • Country: us
  • Retired, now restoring antique test equipment
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #9 on: February 06, 2023, 07:09:16 pm »
One detail I remember from that series of DOS laptops.
The printer parallel port also served as a connector for an optional external disk drive.
Therefore,  the driver for that port had a faster rise time than normal "Centronix" ports.
That caused me some difficulty using a commercial parallel port to general-purpose logic output box, due to crosstalk on the cable.
(Also, the external box did not terminate the input properly.)
 

Offline c64

  • Frequent Contributor
  • **
  • Posts: 300
  • Country: au
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #10 on: February 07, 2023, 10:38:18 pm »

- Battery charger works, as an experiment, I charged up six NiMh cells with it, and it would run on that just fine.


How many NiCd cells were in the original battery pack? Internet says 4, but it wouldn't be 7.2V then
 

Offline vasonline

  • Contributor
  • Posts: 23
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #11 on: February 08, 2023, 01:41:56 pm »


How many NiCd cells were in the original battery pack? Internet says 4, but it wouldn't be 7.2V then

There were 6 of them.

With the DC IN led lit, but the rest of the laptop still powered off,
you could see the charge pulses onto the battery pack terminals. (with scope).

The TL1451A on the M/B has been an important chip for me, to check. together with the scope Shots from Thom.
(a big thanks to him for putting that online- it was very helpfull at the time)









« Last Edit: February 08, 2023, 01:57:28 pm by vasonline »
 
The following users thanked this post: c64

Offline c64

  • Frequent Contributor
  • **
  • Posts: 300
  • Country: au
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #12 on: February 09, 2023, 08:09:05 pm »

- You _do_ need the hard disk installed. There is a switch on the MB/HDD that will press in when installed. Laptop wil turn on and will shut off w/o HDD. Very confusing!


Is it enough to just press the switch?
 

Offline vasonline

  • Contributor
  • Posts: 23
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #13 on: February 11, 2023, 01:21:16 pm »

- You _do_ need the hard disk installed. There is a switch on the MB/HDD that will press in when installed. Laptop wil turn on and will shut off w/o HDD. Very confusing!


Is it enough to just press the switch?

Yes.
 
The following users thanked this post: c64

Offline GRADIENT

  • Newbie
  • Posts: 2
  • Country: fi
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #14 on: March 16, 2023, 03:23:18 pm »
I had pretty much all of the electrolytic capacitors leaking badly inside the laptop. Also all four of the 220uF 25V caps had leaked all over the place. I tried recapping and cleaning the board but still does not boot. Battery charging works fine and laptop even tries to start with the original battery without power supply.

Some traces in between the IC505 and the C506 cap were corroded. I doubt, but I'm just wondering if anyone has removed IC505 and has a picture of the PCB below the IC. I Would like to check the continuity of the traces under the IC but would rather not remove the IC especially if it is not absolutely necessary. Also, still unsure whether I should go any further with the repair.


Edit:
By the way, if anyone needs a list of electrolytic capacitors for the laptop (I did not open LCD) then this is the list that I measured (no guarantees) when I recapped mine:
1x 1000uF 6.3V 8x20mm
2x 220uF 35V 8x20mm
2x 120uF 25V 6.5x14mm
2x 220uF 10V 6.5x12mm
4x 220uF 25V 10x13mm
« Last Edit: March 16, 2023, 04:08:23 pm by GRADIENT »
 
The following users thanked this post: EEVblog, c64

Offline c64

  • Frequent Contributor
  • **
  • Posts: 300
  • Country: au
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #15 on: June 24, 2023, 11:12:33 pm »
Dave if you feel lucky, there is one on eBay now

https://www.ebay.com.au/itm/304988392304
 

Offline EEVblogTopic starter

  • Administrator
  • *****
  • Posts: 37934
  • Country: au
    • EEVblog
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #16 on: June 27, 2023, 11:52:54 am »
Dave if you feel lucky, there is one on eBay now
https://www.ebay.com.au/itm/304988392304

Sadly not the same model. Could have done a screen swap if it was.
 

Offline FuST

  • Newbie
  • Posts: 5
  • Country: nl
Re: EEVblog 1527 - Toshiba T1000LE DOS Vintage Laptop Repair HELL
« Reply #17 on: September 12, 2023, 06:59:12 am »
Just stumbled upon this thread, I might be able to help some people out here.

I'm a bit swamped at the moment but I can provide measurements and/or 'scope shots from a couple of working T1000LE's to cross-check if someone wants to.

Some traces in between the IC505 and the C506 cap were corroded. I doubt, but I'm just wondering if anyone has removed IC505 and has a picture of the PCB below the IC.
I can take some pictures if you're not comfortable removing it from your board.
I'll have to dig up one of my machines and suck the IC out when I find the time so it'll take a while, trying to figure out which rail is failing is probably a bit quicker.

My usual approach with the T-series PSU sections is something like this:
- Remove all large capacitors used in the buck/boost converters (the ones hanging of the side of the board on the T1000LE.
- Thoroughly clean the board with vinegar, water and IPA to remove all the gunk
- Replace with new caps (I tend to use Panasonic FC series)
- Hook up a 'scope to all the power rails (+5, +12, -12, -22, they're the jumperlinks near the center of the board)
- Set to single-shot and power on the machine (a 4-channel 'scope is really handy for this), check for misbehaving rails.

That way it's easier to narrow down the problem to one of the voltage rails instead of trying to look at the board as a whole.

I attemped to draw a (sort of) schematic of the PSU (very incomplete)

I'll post it here, maybe it is helpful?

If you could upload the files somewhere that'd be very helpful.
I can see if I can combine it with the incomplete schematic I have for these and perhaps create a complete schematic for this machine.
 
The following users thanked this post: c64


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf