Discussion:
Apple IIc rom upgrade - not functioning
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Chris Rupnik
2018-02-10 18:58:16 UTC
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Hi
I purchased a rom upgrade for my IIc and it does not appear to be working. I did follow the instructions, matching what is posted on the web a about cutting the W1 and soldering W2.

The symptom is that when powered on either with or without keyboard to trigger the self test, the screen has rows of inverse white and black bars. Curiously, the screen looks the same if there is _no_ rom installed, leading me to believe that the rom isn't ok, but that seems unlikely to me. Do Eeproms get erased easily? Like in a airport x-ray scanner (i did travel quite a bit with the eeprom in a carry on bag)

If i re-install the original 255 rom - there is the check for floppy and a control reset will bring up to applesoft, but strange things happen - i suspect due to the W1/W2 being in unexpected conditions.

Has anyone ever tried to see what happens when putting back in a 255 rom _after_ W1 and W2 are adjusted for a later rom?

Thanks

Chris
Michael J. Mahon
2018-02-10 21:55:55 UTC
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Post by Chris Rupnik
Hi
I purchased a rom upgrade for my IIc and it does not appear to be
working. I did follow the instructions, matching what is posted on the
web a about cutting the W1 and soldering W2.
The symptom is that when powered on either with or without keyboard to
trigger the self test, the screen has rows of inverse white and black
bars. Curiously, the screen looks the same if there is _no_ rom
installed, leading me to believe that the rom isn't ok, but that seems
unlikely to me. Do Eeproms get erased easily? Like in a airport x-ray
scanner (i did travel quite a bit with the eeprom in a carry on bag)
If i re-install the original 255 rom - there is the check for floppy and
a control reset will bring up to applesoft, but strange things happen - i
suspect due to the W1/W2 being in unexpected conditions.
Has anyone ever tried to see what happens when putting back in a 255 rom
_after_ W1 and W2 are adjusted for a later rom?
Thanks
Chris
It wasn't the x-ray machine.
--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
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