atar wrote on 2025-12-22, 12:21:

Thermalwrong wrote on 2025-01-18, 16:09:

The main cap that should be bad on the T1960 will usually be C511 which is 6.3v 1000uF.

Sorry for a dumb question, going to replace the C511, have just ordered a soldering station with a heat gun. What would be the best approach on replacing C511? Iron solder or a heat gun? And what temperature would be the best? I'm afraid if I set it too low, I would overheat the neighbouring components waiting till it starts working, and the same would definitely happen when I set it too high.

A heatgun or hot air station on the area is pretty risky, there are lots of SMD components on the back where you need to remove the capacitor's legs from. Simply heat one leg with a soldering iron and try to 'rock' the capacitor out on that leg, then heat the next leg and rock it out on the other side.
It'll probably take going back and forth a few times but it's the cleanest way I've found to remove caps in busy areas. For an idea of the tip I'd use to do it, look at the BC2 soldering tip.

The PCB isn't too bad for ground plane heating issues so you should have little trouble getting the cap to remove. Once the cap is off, clean up any electrolyte visible on the board around where the cap was with a cotton bud soaked in IPA.
Personally I then use a solder sucker to clear the holes and this can be a bit challenging. Solder wick might work but would be best on the top-side of the PCB since there are so many components surrounding the cap legs on the underside.

Good luck with the repair 😀

Thermalwrong wrote on 2025-12-24, 17:59:

Good luck with the repair 😀

Thanks, managed it. The next quest is the floppy drive. Tried a random rubber belt, but it wasn't flat, so it hadn't had stayed long enough to test whether the belt was the only problem. Not sure whether it makes sense to spend 8 Euro on EBay to get a belt replacement risking that this is not the only faulty part, or to try fining a new drive. This Citizen drive kinda looks like the modern USB drives, so maybe it's better to find a Citizen-based USB drive and use it as a donor?

The replacement of C511 worked for a few days, but now the problem came back, sort of. In the morning the laptop starts, and works some minutes, maybe up to two hours, and then suddenly switches off with LED indicating the PSU error. After disconnecting and re-connecting the PSU, the LED is just on, but the laptop won't start with the symptoms it had before the C511 replacement. And then it takes a few hours till something cools down, and it can start again. So, the problem looks like the opposite to the problem Thermalwrong mentioned on the first page: in his case the laptop started after heating, and in my case after cooling. What can it be?

atar wrote on 2026-01-06, 10:05:

The replacement of C511 worked for a few days, but now the problem came back, sort of. In the morning the laptop starts, and works some minutes, maybe up to two hours, and then suddenly switches off with LED indicating the PSU error. After disconnecting and re-connecting the PSU, the LED is just on, but the laptop won't start with the symptoms it had before the C511 replacement. And then it takes a few hours till something cools down, and it can start again. So, the problem looks like the opposite to the problem Thermalwrong mentioned on the first page: in his case the laptop started after heating, and in my case after cooling. What can it be?

Ah that's a shame - what model is it out of the T19x0 series?

Capacitors can drift into spec when they're heated up by reforming a little temporarily, but they could also drift ouf of spec possibly if the capacitors are bad. Potentially it could also be leaked electrolyte still on the mainboard that's becoming conductive and causing a short but possibly only once the mainboard becomes warm does it become conductive enough to cause the short.

Cleaning the mainboard in an ultrasonic cleaner would be ideal as I've resolved similar issues with leaked electrolyte in the past doing that. But there could be more bad caps still if it's the original T1900 and not T1910/50/60 mainboard, see page 1 for the other caps that need changing if it's a T1900 original mainboard.

If you don't have an ultrasonic cleaner and you have a T1910 / T1950 / T1960 mainboard, could you post a picture of the mainboard in the C511 area so we can see if there are any other suspect caps?

Thermalwrong wrote on 2026-01-07, 02:29:

Ah that's a shame - what model is it out of the T19x0 series?

It's T1950CT. I blame my soldering skills. Re-soldered it yesterday, and now the system seems to run stable again. Thank you one more time!
The next challenge is the citizen floppy drive driving me crazy, I've started another topic for that,to keep this one PSU-related.

What temperature C504 and C509 should work at? Just noticed that mine are getting something like 55-65 °С hot. Should I start worrying? The system seem to work stable.

Hi all

Sorry again to also "revive" this old topic.
Following the instructions here and some videos available in internet I was able to change 3 big capacitors:
C504
C509
C511

After capacitors changed, the laptop was able to boot and all working without problems.
I "refurbished" the 12v PA2420u Li-ion battery with rechargable Li-ion batteries (10 x AA Li-ion batteries in serial) also the termal fuse and the other component I cant remember the name, both desoldered and soldered again.

The computer boot and It is running around 2hours without power supply.
The matter is when I try to recharge the battery. The battery led is in ORANGE for about 5 secons and then Led is off and the DC GREEN led is flashing 4 times then off, then flashing 4 times, then off, then ...

Still there is a inter power circuit problem? May be more capacitors to the change in battery circuit area?
I tried to now if these 4 times the DC GREEN led is flashing is the same situation before the 3 big capacitors were changed.
With the videos showed in internet with the internal power supply don't show how may times the DC GREEN led flashes.
Could some explain if also 4 times flashing?

Regards

Jason_rg wrote on 2026-01-29, 21:56:

I "refurbished" the 12v PA2420u Li-ion battery with rechargable Li-ion batteries (10 x AA Li-ion batteries in serial) also the termal fuse and the other component I cant remember the name, both desoldered and soldered again.

The attachment 1Original.jpeg is no longer available

The computer boot and It is running around 2hours without power supply.

Nice! Thank you very much for the picture, I plan to revive my battery too. What is that "other component"? According to the Toshiba connector definition, there is some kind of battery control line between the "+" and the first "-" pins. Did you connect something there?

Jason_rg wrote on 2026-01-29, 21:56:

The matter is when I try to recharge the battery. The battery led is in ORANGE for about 5 secons and then Led is off and the DC […]
Show full quote

The matter is when I try to recharge the battery. The battery led is in ORANGE for about 5 secons and then Led is off and the DC GREEN led is flashing 4 times then off, then flashing 4 times, then off, then ...

Still there is a inter power circuit problem? May be more capacitors to the change in battery circuit area?
I tried to now if these 4 times the DC GREEN led is flashing is the same situation before the 3 big capacitors were changed.
With the videos showed in internet with the internal power supply don't show how may times the DC GREEN led flashes.
Could some explain if also 4 times flashing?

Flashing 4 times is an error. I guess some of this 4 times are long and some are short? For me it blinked some code before I had replaced c511, and also blinked some other code as I tried connecting a completely discharged battery. I haven't succeeded finding the 4 bit Toshiba error code table. There is a 8 bit table available, but my code there has made no sense, so probably it's not backwards compatible with the older 4 bit error table.
I have a similar problem and started this topic. For me charging works if a laptop is turned on while the orange LED is still on. The led goes off but the battery is charging (the details are in that topic). Have you tried that?

Hi Atar

In my "refurbished" battery the GREEN cylinders have 2 AA li-ion batteries inside (same than the original one) and these cylinders are connected in serial, but between cylinders 1 and 2 there is a termal fuse, and 4 and five there is a may be varistor¿?(not sure).

The fist pad that is showed in red+ in the front of battery case is the initial point internally soldered to the + in first green cylinder, then the fuse (for protection) from - to + in the next cylinder 2 then cylinder 3 then 4 then varistor¿? (for protection) then cylinder 5 where it's - is connected to the pad 4 marked in red - in the battery case.

Replying to the Pads on battery case, Pads 1,5 there are 12volts, Pads 2, 3, 4 in battery case is connected to a thermal sensor (for protection), not sure is 2 to 3, 2 to 4 or 4 to 3

When connecting the batter to the computer to recharge, the orange led is 5 seconds on, then off and DC green led flash 4 times short and stops, then 4 times short again and stops, continuously.

I suspect the batter is recharging anyway. Will test after looking your topic.

Hi again

Well ... the battery is not charging, obviously ...

Let's see if there is somewhere there is info about flashing leds means.

Regards

Hi

Attaching picture with connections for the original battery:

Regards

Jason_rg wrote on 2026-01-31, 10:09:

Attaching picture with connections for the original battery:

The attachment 4Original.jpg is no longer available

Looks like something went wrong with the attachment.

Have you tried powering on the laptop without the battery and put it in while it is on? Do LEDs somehow react in this case?

Hi

Attaching image:

download/file.php?mode=view&id=235479

Regards

Hi again

As per maintenance manual power supply is 18v 1.1 for my T1910?
But I can't find Toshiba 18v, the minimum I cand find is 19V.
Is there any problem if I use 19V?

Regards

Jason_rg wrote on 2026-01-29, 21:56:

Hi all […]
Show full quote

Hi all

Sorry again to also "revive" this old topic.
Following the instructions here and some videos available in internet I was able to change 3 big capacitors:
C504
C509
C511

After capacitors changed, the laptop was able to boot and all working without problems.
I "refurbished" the 12v PA2420u Li-ion battery with rechargable Li-ion batteries (10 x AA Li-ion batteries in serial) also the termal fuse and the other component I cant remember the name, both desoldered and soldered again.

The computer boot and It is running around 2hours without power supply.
The matter is when I try to recharge the battery. The battery led is in ORANGE for about 5 secons and then Led is off and the DC GREEN led is flashing 4 times then off, then flashing 4 times, then off, then ...

Still there is a inter power circuit problem? May be more capacitors to the change in battery circuit area?
I tried to now if these 4 times the DC GREEN led is flashing is the same situation before the 3 big capacitors were changed.
With the videos showed in internet with the internal power supply don't show how may times the DC GREEN led flashes.
Could some explain if also 4 times flashing?

Regards

Good morning

Sorry for my mistake, the rechargable batteries for above are all Li-Mh and not Li-Ion. The old ones and new ones.

10 x AA 1,2 v = 12v

Li-Ion are 3,7v

I'm testing about charging battery with computer on and running. In this situation, It looks battery is charging? I will conform later.

Regards

Jason_rg wrote on 2026-02-01, 08:58:

I'm testing about charging battery with computer on and running. In this situation, It looks battery is charging? I will conform later.

In my case it is charging if I turn the laptop on as the orange/amber led is still on. If I turn the laptop on after the orange/amber led turnes off, it doesn't charge.
According to the manual, the full charging time while on is 48 hours.

Hi atar

Well ... Even if the orange led turns off with external power supply connected, when turning on the laptop the orange led is off and leaving the computer on during some hours ... the battery is charging¿?
It looks is charging but not full.
From the beggining before turning on the laptop, the battery had 11,70v (without charge) and after 4 hours with laptop on, the battery have 13,50v (without charge). The laptop with only battery with no external power supply It not running for 2 hrs as from the begging but around 40 minutes.

Extrange...

Anyway it will be usefull to know about the green led flashing meaning. If someone know will help, because may be even if changing only 3 big capacitors on laptop power supply, there are more problems with the other capacitors affecting to battery charging circuitry.

Regards