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Some Motherboard Bios Programming Questions

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First post, by dicky96

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Hi guys
I've got a few old motherboards lying around now that don't post or beep when powered up, even with a known good PSU.

That's with just the mobo + CPU or mobo + CPU + RAM fitted

The capacitors look good on these boards, just by a visual check though, I didn't pull them and put my Capacitance and ESR meters on them to check.

I was wondering how often this type of fault is caused in general by corrupted BIOS? Also how often does a similar sort of problem cause graphics cards to not be recognised, even though there is no short circuit or similar problem?

Also what sort of eprom programmers are the best to suited for this use? I've done some googling around and it seems the TL866A or TL866ii programmers are popular and well suported. Is anyone using either of these to reprogram BIOS chips? It seems the difference main difference between the two models is:

TLL866ii
minium Vcc 1.8V support – enhanced from 3.3V
maximum Vpp reduced to 18V – down from 21V
NAND flash support
512MB flash support – up from 128MB

These TL866 programmers just look so 'cool' the nerd in me wants one even if i may not need one 🤣!

However it would be interesting to know if I am likely to revive a reasonable amount of those 'dead' motherboards and VGA cards

I've programmed Eproms in the past but that was like nearly 30 years ago..... but I do have some idea of the process required. I'm skilled enough to be able to remove and resolder SMD chips if neccessary and have the kit to do so.

So in short:

1. Is faulty BIOS a common cause of motherboards that just won't POST/Beep? (common enough to expect a reasonable repair rate vs cost of the kit to do it)
2. Are either of the TL866 programmers a good choice... For older/vintage motherboards as well as modern ones?
3. Is it usually the BIOS chip itself that is faulty, or the contents that are corrupted?
4. Generally speaking, is it easy to find replacement blank devices to program and the firmware to write to the chip?

Hopefully someone has the experience to shed some light on this topic

Thanks
Rich

Reply 1 of 4, by Predator99

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1. Is faulty BIOS a common cause of motherboards that just won't POST/Beep? (common enough to expect a reasonable repair rate vs cost of the kit to do it)
Depends. I have not seen many corrupted BIOS on 2/3/486 as the ROMs are not rewritable. But more damaged ones starting from 586 as the user is able to reprogram the EPROM on his own. When failing the update the board was dead.

2. Are either of the TL866 programmers a good choice... For older/vintage motherboards as well as modern ones?
Yes, very good choice!

3. Is it usually the BIOS chip itself that is faulty, or the contents that are corrupted?
Both possible.

4. Generally speaking, is it easy to find replacement blank devices to program and the firmware to write to the chip?
Yes no problem to find blank devices. For me the W27E512 is a good choice for every purpose up to 486. But especially for older boards it may be difficult to find a working copy of the ROM.

Reply 2 of 4, by dicky96

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Thanks Predator99

One more question...

Am I likely to need the 1.8V support of the TL866iii? as opposed to being able to program old Eproms that need 21V Vpp?
Considering most of the motherboards I am likely to be working on are Socket 7 and later

Reply 3 of 4, by Predator99

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dicky96 wrote:
Thanks Predator99 […]
Show full quote

Thanks Predator99

One more question...

Am I likely to need the 1.8V support of the TL866iii? as opposed to being able to program old Eproms that need 21V Vpp?
Considering most of the motherboards I am likely to be working on are Socket 7 and later

Dont know...I have the TL866CS and never missed anything...

Reply 4 of 4, by dicky96

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Predator99 wrote:

2. Are either of the TL866 programmers a good choice... For older/vintage motherboards as well as modern ones?
Yes, very good choice!

I ordered a TL866A today with the 10 adapters

I figured I may need the 21V programming option and as the TL866A is no longer in production apparently (replaced by the TL866ii) I decided to get that one now while they are still available, albeit a bit more expensive than the newer model.

I'm looking forward to it arriving in about a week 😀

I can always get a TL866ii later if I find I need to program 1.8V devices.

Rich

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