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Broken Apple IIe - garbage screen

Interesting. I've never heard of or seen an Apple II ignore the card and just go to Basic ] prompt but that's why your's does. The first 4 bytes are the card ID.
If the ID is not found, the computer keeps scanning slots, then exits to basic. A $20 in place of $00 means that bit 5 is always set. What are the next 4 bytes?
They should be A2 03 86 3C. If those have bit 5 set they will be A2 23 A6 3C. If so, try reseating the P5 and P6 proms on the card. For that matter, you could reseat them all.
I assume the card is fried but maybe not. It could also mean a prom is bad but in that case you will need another card anyway.
 
Well bit 5 appears to be set as the following bytes are A2 23 A6 3C.

Sooo, I suppose replacing some of the replacable chips and conponents are in order.
Do you have a schematic of the drive controller?
 
What you need is the SAMS Photofact CC-10 for the Apple IIe I found here http://apple2online.com/web_documents/Sams Computerfacts Apple IIe KB.
The drive controller schematic is split between p4 and p33 of the paper.
Hmmm - looking at page 4, the 8 data lines D0-D7 from the motherboard only go to shift register UC3 74LS323 and UD3 P5 prom. Try pulling out UC3 (74LS323 - 2nd up from bottom left) then power on and look at the bytes at C600 again to see if normal now ??
If so, UC3 is bad. When you boot w/o that chip it might crash into * monitor or hang. If hangs, just reset to ] prompt then check the bytes.
 
What you need is the SAMS Photofact CC-10 for the Apple IIe I found here http://apple2online.com/web_documents/Sams Computerfacts Apple IIe KB.
The drive controller schematic is split between p4 and p33 of the paper.
Hmmm - looking at page 4, the 8 data lines D0-D7 from the motherboard only go to shift register UC3 74LS323 and UD3 P5 prom. Try pulling out UC3 (74LS323 - 2nd up from bottom left) then power on and look at the bytes at C600 again to see if normal now ??
If so, UC3 is bad. When you boot w/o that chip it might crash into * monitor or hang. If hangs, just reset to ] prompt then check the bytes.

Tried removing the LS323 and dropping the card back into the slot, but nothing changed!
Bytes are still the same. No crash occurred on the Apple ][ though, which was interesting.
I guess some other components have fried. I wonder what a busted C2 cap could have ruined...

If the LS323 is busted, I can't get local IC replacements of that one. I may be better off getting a new card.
 
You actually proved the LS323 is good and probably the P5 PROM is bad. Yea, time for a new card ...
I also found in this forum that having the ribbon reversed could fry the 74LS125 inside the drive on the analog card.
That wouldn't cause the bit 5 problem, though.

Good luck

Larry G
 
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