I have a 430CDT and a 440CDT in my collection. If i can do some measurements or can help in any other way let me know. I also have a Eprom reader... but i dont know if i can read the Bios off my 430. I have never taken it apart and i dont know if the BIOS chip is socketed. ... I hope they still work 😁 . The last time i turned them on was 2 years ago.

Thank you but first I need to figure out what's even going on with these laptops and... at this point I wouldn't be surprised if your 430 just dies after a short period of time. These results are severely inconsistent. I tried to boot up the 430CDS a few times and sometimes I got other error codes: 90h and 7Eh. Maybe 90h makes sense but 7Eh doesn't. I also got another LED error code of D1h on 430CDT which doesn't make sense either. By the way, here's the actual service manual:
http://minuszerodegrees.net/manuals/Toshiba/S … ce%20Manual.pdf

I have no idea what to think about this. Are the CPUs just dead? Should I even try?

EDIT: so I experimented a little bit more with the 430CDS and it looks like I got a little bit more "life" out of this. By saying that I mean the LEDs on the LPT port light up at random at first but after that they are supposed to turn off and the caps lock LED is supposed to blink. Here's the turn of events I sometimes get:

1. I turn on power and keep holding the spacebar the entire time (Toshiba manual states it is supposed to turn on diagnostic mode or something like this)
2. The ON LED turns on
3. LEDs on the LPT port turn on (sometimes some or all of them)
4. The caps lock LED blinks once
5. LEDs on the LPT port turn off
6. I hear some beeps and the HDD activity LED turns on and the PC tries to read from the floppy drive (I believe it prompts me to repair the BIOS but nothing is displayed on the screen this time)

I rarely get to point 6, sometimes I get to point 5 but the majority of times I just get to point 3 but other times I only get to point 2... Well, I read somewhere that the BIOS chip is supposed to blink the caps lock LED 3 times on these Toshiba machines and after that it boots up. Is this what really should happen? Well, all I get is rarely a single blink and this is the best I can get. Considering how randomly it works- I suppose the system clock is damaged? Or even worse the CPU itself..... or maybe it is something as obvious as recapping all PCBs but I really doubt it. Please let there be here someone with advanced knowledge...

Random behavior like this is usually power related.
1 you need to stop powering those machines on constantly hoping for another outcome https://www.etsy.com/listing/660310829/the-de … ty-is-doing-the
2 you need top open them up to the point motherboards can be removed and inspected
3 check for battery leak damage
4 check all power rails with oscilloscope

it might be too much for an amateur, so find a technician willing to help.

DerBaum wrote on 2022-07-27, 11:25:

I hope they still work

I tested my 430 a little bit and left it plugged in. It still works and even the battery is holding some kind of charge.
It only complained once that the Cmos battery is probably broken, but after that it booted fine.

BlackVega wrote on 2022-07-27, 12:04:

Should I even try?

Depends on what you want to do with it.
It feels a little bit slow for windows games. Probably because the graphics chip isnt that fast.
And the FM from the soundchip is clearly not Yamaha. It sounds fine but the hihats and snares sound a little bit harsh and metallic in this FM implementation.

rasz_pl wrote on 2022-07-28, 05:56:

Random behavior like this is usually power related.

Ah yes this is what I figured out as well after so many tries. It is probably power related or some sort of global issue because every time the outcome was drastically different with no consistency. Actually I unscrewed the 430CDS and it looked clean but upon closer inspection, I noticed just a very tiny little bit of corrosion but nothing significant, it will probably be very easy to clean. 430CDT was absolutely crystal clear inside. I just measured all voltages on fuses and they all looked fine but I was using a multimeter. Using an oscilloscope is probably a good idea but what I have is a mini super pseudo portable shit oscilloscope that maybe would help, maybe not. Oh well, maybe I will rent a professional one and follow up

the kit shitoscope will be fine, all you want is to see if there is any ripple <1MHz on power rails (12 5 3.3 and CPU vcore probably generated separately). This would signal bad capacitors.
First things first is getting rid of everything non essential. Unplugging backlight inverter, screen, disk, floppy, ram etc and seeing if things get better on external VGA output. "BIOS is damaged" is most likely generated after failing BIOS CRC check - might be corrupted bios, or bad ram, or fluctuating power making cpu unstable executing with errors.

> tiny little bit of corrosion but nothing significant, it will probably be very easy to clean

you need to at least resolder parts that were affected, and have some way of verifying those parts of the circuit actually work correctly

I try to come back to repairing those laptops. I can see there is some battery leakage on the motherboard. Not huge but it's still there. Just tested some tracks with a multimeter and they still connect. I will dig deeper later. I'm thinking about doing a recap but right now I can see there are just some electrolytic caps and a whole bunch of oscon caps. I know regular caps are almost always supposed to be replaced but how about os-cons? Are they also supposed to be replaced and are they also prone to failure? If yes then are the replacements also supposed to be os-cons?