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EPROM in need of re-programming

P

per

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I just realized that the ROM chip on one of my ATI EGA Wonder 800+ cards were inserted upside down, and when inserted the correct way; the computer complains that no video card is present.

This means that the EPROM on the card is either dead or corrupted, and I will need to have a new one programmed. Luckily I have another card with just the same BIOS version, so I have made a dump of what the EPROM should be. However, I don't have any kind of EPROM programmer, nor the capability of ereasing previously used EPROMs, so I would be thankfull if anybody could offer to do this.

I will pay for parts needed and shipping.
 
carlsson said:
What is the model number of the EPROM, as not all programmers are capable to handle all chips?
Click to expand...

It's just a regular 27C256. 32x8Kb, 27x standard pinout.

The big question is if the old chip can be reprogrammed or if a new chip has to be purchased. I've had other EPROMs surive a power-reverse, but this one seems to have been affected in some way.
 
Hi! Reverse biasing is usually instant smoky death for TTL chips. Occasionally one may appear to survive but you can bet its been damaged severely and I would not consider it a reliable part any longer.

Maybe if you are lucky you can read the contents of the EPROM but I would not consider reusing that part especially for a relatively low cost common chip such as 27C256. Do you have the contents of the ROM or can you get it from someplace?

Thanks and have a nice day!

Andrew Lynch
 
lynchaj said:
Hi! Reverse biasing is usually instant smoky death for TTL chips. Occasionally one may appear to survive but you can bet its been damaged severely and I would not consider it a reliable part any longer.

Maybe if you are lucky you can read the contents of the EPROM but I would not consider reusing that part especially for a relatively low cost common chip such as 27C256. Do you have the contents of the ROM or can you get it from someplace?

Thanks and have a nice day!

Andrew Lynch
Click to expand...

As I mentioned, I had two of these cards with the similar BIOS revision, so I do have a dump of what it's supposed to be.
 

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Your chips are almost certainly toast--I've never seen an UVEPROM that could withstand the "backwards" treatment. Unless you're stuck on the idea of original equipment, you may want to consider replacing them with EEPROMs, which most fairly recent programmers can handle. The advantage is that you don't need to use an UV eraser on them and they generally program faster.
 
Any programmer should be able to handle 27256's though. They're EXTREMELY common - finding a replacement will be easy.

And yes, I agree, backwards EPROMs usually are toasted - although I have in the past salvaged one by programming it full of zeroes and erasing it a couple times. On some chips, if the window is uncovered and you plug it in backwards you can see the die glowing...

-Ian
 
jackrubin said:
you plug it in backwards you can see the die glowing...for a very short time - it's the "oh sh!t" indicator light. :>)
Click to expand...
Hi Jack!

Sounds like fun; I've got enough of 'em that I'll have to try that ;-)

After all is said and little done, did per actually get an EPROM?
 
carlsson said:
Ooh... did the chip get damaged?
Click to expand...

The chip should be fine. Electronics without charge (no batteries or charged capacitors) usually handles water just fine, unless it starts corroding. However, in most cases it have to be exposed quite a while to water before this happens.
 
I have a cheapo Willem EEPROM programmer which I believe supports this device. If you have a chip to send me I can try programming it.
 
Hi per,

Did you check the speed of the device you're replacing?

Anyone using a Willem type programmer needs to know what they're doing to program EPROMs reliably. They're hobbyist programmers and much of the intelligence is in the User, not the programmer/program.

Don't use a device that was inserted backwards, even if it appears to be functional; it's a time bomb.

Regards,
Dennis
 
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