Thank you. That sucks. I wonder if a bad cap would cause my issue.
Do you see the following? I am using version 2.00 of the IBM AT Advanced Diagnostics.
STEP 1
Have only the first bank of the memory card populated. Run the AT Advanced Diagnostics. At the applicable point within the '24' test, do you see "128KB GRAPHICS MEMORY INSTALLED. IS THIS CORRECT (Y/N)?" question?
Important: "128KB" - the diagnostic detected 128 KB total video RAM.
The test passed.
STEP 2
Have only the first and second banks of the memory card populated. Run the AT Advanced Diagnostics again. At the applicable point within the '24' test, do you see "192KB GRAPHICS MEMORY INSTALLED. IS THIS CORRECT (Y/N)?" question?
Important: "192KB" - the diagnostic detected 192 KB total video RAM.
The test passed.
STEP 3
Have all three banks of the memory card populated. Run the AT Advanced Diagnostics again. At the applicable point within the '24' test, do you see "256KB GRAPHICS MEMORY INSTALLED. IS THIS CORRECT (Y/N)?" question?
Important: "256KB" - the diagnostic detected 256 KB total video RAM.
Is this where you see 192 KB ?
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As as an experiment, I populated only the first and second banks. As expected, the diagnostic asked "192KB GRAPHICS MEMORY INSTALLED. IS THIS CORRECT (Y/N)?". I answered 'N' then when prompted to enter the amount, I entered in 256. As expected, the diagnostic reported an error when it tested the non-existent third bank. The code shown was 030011.
As an experiment, I fully populated the memory card, then removed RAM chip U6. The diagnostic asked "192KB GRAPHICS MEMORY INSTALLED. IS THIS CORRECT (Y/N)?". That did surprise me, because with only one chip at fault (missing in this case) in the third bank, I thought the diagnostic would have been smart enough to realise that all three banks were present. I answered 'N' then when prompted to enter the amount, I entered in 256. As expected, the diagnostic reported an error, showing code 030201, the code expected for a faulty U6.