Electronics > Repair
What more i can do?
Harry_22:
OP, you found out that the board has battery powered SRAM a week ago and didn't say anything.
I would like you to be more attentive.
Here we must take into account the nature of the malfunction and pay special attention to bottlenecks.
Although I am not sure that the SRAM is activated at the beginning of loading.
On a similar machine this 24-pin SRAM is located next to the EPROM.
CaptDon:
Anyone feel like this thread will go to 28 pages and the unit still not work?
PA0PBZ:
It looks like the OP has lots of boards with the same error: "I have lots of those boards with 99% having the error of beep" so maybe it would be a good idea to send some out to people that could maybe diagnose the problem?
fzabkar:
--- Quote from: Harry_22 on November 27, 2024, 09:55:35 am ---OP, you found out that the board has battery powered SRAM a week ago and didn't say anything.
I would like you to be more attentive.
Here we must take into account the nature of the malfunction and pay special attention to bottlenecks.
Although I am not sure that the SRAM is activated at the beginning of loading.
On a similar machine this 24-pin SRAM is located next to the EPROM.
--- End quote ---
I think the OP and I are somewhat overwhelmed. That other thread at Reddit was a dead end. I took the OP down the wrong track because I was convinced that expensive industrial equipment, for which downtime is critical, would have a diagnostic port to facilitate rapid fault finding by a field tech. In fact, I didn't want to get involved here because I didn't want to pollute this discussion with remnants from the other.
I think you're doing a great job, given the lack of documentation and the time delay. I'm wondering at which point the BIOS code stops executing. At some time early in the POST, the BIOS must compute a checksum over its contents. This means it needs to read 512K bytes at a clock rate of 66MHz. That's at least 512K instructions, with a 15ns clock. If EPROM access comes to a halt before the checksum routine can start, then perhaps that will tell us something.
222Lab_Test222:
--- Quote from: Harry_22 on November 27, 2024, 09:55:35 am ---OP, you found out that the board has battery powered SRAM a week ago and didn't say anything.
I would like you to be more attentive.
--- End quote ---
Whats the thing with SRAM? Sometimes there is lots of comments and i may miss some messages of comments sometimes.
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