Frasco wrote:

Yes, I used that photo. My motherboard is equal, however i am using a Cyrix 586 and 32MB of RAM (2X16 FPM). […]
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Yes, I used that photo. My motherboard is equal, however i am using a Cyrix 586 and 32MB of RAM (2X16 FPM).

Thats great. Thats FREAKING great.

Now everyone knows I own a worthless 300$ equipment. Very well, detective. 🙁
Keropi probaby wont raise a finger to help me. 😵

Ask the guy selling it if he can get a BIOS dump, or offer $10 for a BIOS chip "rental" 🤣 😎

You are bad... 🤣

He's talking big. He and the manufacturer will not play favours.

I've found them (Hong Kong). ALD stopped AT motherboard bussiness a long time ago.
I can see they still support one AT MOBO though.

You're better off playing around with a programmer and trying to get it to read the broken chip if the seller doesn't answer. Even if that doesn't fix it, having a programmer is always handy.

alexanrs wrote:

You're better off playing around with a programmer and trying to get it to read the broken chip if the seller doesn't answer. Even if that doesn't fix it, having a programmer is always handy.

Seu nome é Alexandre ? Alexandre, eu vou verificar sua dica. Não existe também um EPROM programmer (mais barato) ?
O Chip Eeprom ou Eprom eu já encontrei no Aliexpress. Passa seu e-mail por favor. Aqui não dá pra falar assim em português. Eu também não quero subir mais o tópico.

Obrigado carinha, pela vontade de me ajudar.

Frasco wrote:

Seu nome é Alexandre ? Alexandre, eu vou verificar sua dica. Não existe também um EPROM programmer (mais barato) ? O Chip Eepro […]
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alexanrs wrote:

You're better off playing around with a programmer and trying to get it to read the broken chip if the seller doesn't answer. Even if that doesn't fix it, having a programmer is always handy.

Seu nome é Alexandre ? Alexandre, eu vou verificar sua dica. Não existe também um EPROM programmer (mais barato) ?
O Chip Eeprom ou Eprom eu já encontrei no Aliexpress. Passa seu e-mail por favor. Aqui não dá pra falar assim em português. Eu também não quero subir mais o tópico.

Obrigado carinha, pela vontade de me ajudar.

English please...

I was about to say that the topic should be kept in english (and yeah, you got my name right). You can always send me a private message in portuguese - just click on the "X new messages" to go to your inbox and create a new PM - in case you need anything.

And have you checked MercadoLivre.com? Last time I checked you could get an EEPROM programmer for reasonable prices there.

Stiletto wrote:

English please...

I'll sue you for police brutality.

All the info that one ever need to solve this kind of problem is here.
What you people did out here was fantastic, passing on the knowledge.
Now it is up to me.

Stiletto, no more swear. I promise. 😜
Cya in the next episode of Captain Baiseballbad-Boy, i mean, thread.

Frasco wrote:

Stiletto wrote:

English please...

I'll sue you for police brutality.

If you'd like to speak in Portuguese, you can still do it in private messages. The big majority of this forum's users speak English, this is why you were asked (English please) to do the same. I can't see any police brutality here even though you were probably joking.

Trevize wrote:

Frasco wrote:

Stiletto wrote:

English please...

I'll sue you for police brutality.

If you'd like to speak in Portuguese, you can still do it in private messages. The big majority of this forum's users speak English, this is why you were asked (English please) to do the same. I can't see any police brutality here even though you were probably joking.

He was joking "brutality" because not only did I request English only, but previously had removed all his "fuck"s and replaced them with "freak", because a. he used it in the subject and b. he was prolific in his post. 😁

But yeah, we need English because moderators cannot otherwise moderate and admins cannot otherwise admin. 😀

Stiletto wrote:

He was joking "brutality" because not only did I request English only, but previously had removed all his "fuck"s and replaced them with "freak", because a. he used it in the subject and b. he was prolific in his post. 😁

At last ! Someone who understand me. 😁

Trevize wrote:

If you'd like to speak in Portuguese, you can still do it in private messages. The big majority of this forum's users speak English, this is why you were asked (English please) to do the same. I can't see any police brutality here even though you were probably joking.

I'm joking around, so nobody notice how shy i am.
"The humam heart, a captive in the snow". 😵
So i try to break the ice.

Thank you for the advice... I was just telling that man i cannot go messing around and talk in portuguese over here. Thanks anyway...

And how about the ROM (just in case) ? Do you ever see the things that i write ? Cover me !

Monster up!

Having 3 motherboards bricked, I finally decided to bite the bullet and get a programmer.

To read the old BIOS chip (without legs) I used 133MHz and HighTreason advice:
"sewing pins have served for this before"
It worked 😀 Trying to record the dump in a "new" BIOS chip, I get this message:

** "new" = no, not this chip...there was data in there.

What's my next step ?

• -Trying to read the old chip again? (content isn't corrupted, but I'm not so sure of this)
  -Erase the new chip? Looks like this chip can be recorded only one time. Heard something about UV...
  -Actually purchase a new BIOS chip ? I'm running out of luck. Couldn't find anyone selling it.

I'm looking for Keropi.
A good thing I've only said: Keropi "probably" won't raise a finger to help me.
Although he must be fighting ghosts and avoiding worms right now.

Seriously, somebody help me...
The profecy will be fulfilled...
Something is telling me this motherboard is beyond repair.
The bad contact between BIOS and the socket probably destroyed it.
I just need to be sure.

Or perhaps she responds to the treatment. I've rescued 2 motherboards so far using this TL866 miniPRO.
Thank you all for the info!

If you're using a TC57512AD chip, those are UV erasable only. You can buy UV eraser's for not too much money, or you can buy another chip. But you need to make sure it is unprogrammed, otherwise you'll still need a UV eraser!

Did you verify it was empty before first trying to program? If not, that's probably the issue. I would grab a 27c512 instead (probably easier to find and looks to be compatible) but again it's UV erasable only, so make sure you get an unprogrammed one.

You could also use an SST 27SF512. These are 27C512 compatible EEPROMS that can be erased in your TL866...no need for UV erasing. I've used them in the past for this exact purpose with great success.

Search on eBay for 27SF512...

Nipedley wrote:

If you're using a TC57512AD chip, those are UV erasable only. You can buy UV eraser's for not too much money, or you can buy another chip. But you need to make sure it is unprogrammed, otherwise you'll still need a UV eraser!

Did you verify it was empty before first trying to program? If not, that's probably the issue. I would grab a 27c512 instead (probably easier to find and looks to be compatible) but again it's UV erasable only, so make sure you get an unprogrammed one.

Uhhh....An obstacle. 😵
Gonna do my homework after some bargain - UV eraser, SST 27SF512 or new 27c512.
I'll try it again...

PS: I am positive. There was data into the TC57512AD chip. He fooled me, although I
payed a small amount for it. Big deal.

FesterBlatz wrote:

You could also use an SST 27SF512. These 27C512 compatible EEPROMS that can be erased in your TL866...no need for UV erasing. I've used them in the past for this exact purpose with great success.

Search on eBay for 27SF512...

Sounds music to me.

Winbond 27c512 are EEPROMs as well (i.e. although they are 27s, they can be erased electronically on a programmer like 886). And can be found fairly cheap at eBay or Ali. Pinout looks compatible with your chip in the screenshot, from what i can see.

GPA wrote:

Winbond 27c512 are EEPROMs as well (i.e. although they are 27s, they can be erased electronically on a programmer like 886). And can be found fairly cheap at eBay or Ali. Pinout looks compatible with your chip in the screenshot, from what i can see.

SST 27SF512 - Two units for 19$ (my currency)
https://pt.aliexpress.com/item/Free-Shipping- … 31-4d7ad07804fb

M27C512 - One unit for 8$ (my currency)
https://pt.aliexpress.com/item/IC-M27C512-12F … 29-3faed8b234d1

UV eraser - 50$
https://pt.aliexpress.com/item/Freeshipping-N … b2-e8447386fd81

Seems like we have a winner here (I think the UV eraser can be of some help to update my FIC 486 PIO-2, but this is a super low priority).

All clear ?

Gonna find some bargain locally.
Gonna be so excited waiting more 30 days for this. Damn....Damn

Some progress on this topic, (ahem) getting more pathetic.

So I recorded the image (64KB) in the new M27C512, installed it in the socket and nothing happened,
again. No codes, no beeps.

This led me to believe something went wrong with the CPU.
I measured the VCC on the socket 3 and here is what I got:

0v or 0.02v in the marked VCCs
5v or 4.8 in the rest (but dammit, the jumpers are set for 3.3V!)

Think about someone really pissed, but I just can't trash this motherboard.
As a side note, CPU and chipset are getting warm.

Is it worse than I thought ?
I'm starting to think this is not going to work. Replacing the voltage regulator will be my last stand.
Other thoughts on how to go about fixing this?

good man, don't trash it!
measure resistance to ground from those pins, if they're not shorted you can solder wires directly from voltage regulator to them. If regulator works.
Although i presume, there are more problems with this board hehe

Frasco wrote:

Some progress on this topic, (ahem) getting more pathetic.
0v or 0.02v in the marked VCCs
5v or 4.8 in the rest (but dammit, the jumpers are set for 3.3V!)

I just repaired a motherboard with a similar fault on Monday. The large output transistor for the CPU series pass regulator had shorted the 5-volt rail to CPU VCC.

Look for a large transistor (likely a TO-220 package like this https://upload.wikimedia.org/wikipedia/common … nt_Coloured.svg) near the CPU socket that's either screwed to a small heatsink or screwed down to the motherboard. Look up the part number and see if you can find a datasheet to show which pin is which. When the board jumpered for 3.3-volt CPU and powered up, carefully measure the voltages on the transistor's pins. They should be:

Emitter: 5-volts
Collector: 3.3 to 3.5-volts
Base: doesn't matter

They key is the collector should be whatever voltage you select via jumpers. If it's always 5 volts, then you likely have a shorted transistor. Replacing it with the exact same part should fix the regulation problem.

What's puzzling is not all the VCC pins showing voltage. Are you sure your probe was making a good clean contact with those pins?