Hi All,
I am looking for some advice. I am restoring an apple ][ europlus which I have had stored away for around 20 years, the machine originally had both a fault PSU and faulty mainboard. I managed to get hold of a spare mainboard which I have installed in the machine and with a small amount of chip swapping from the original I managed to get a working machine. Although the machine would have intermittent video issues such as flickering when a large amount of text was on the screen (e.g. the ADT disk transfer program). note, there was no screen corruption just video noise / colour flickers.
Generally things were great and I got to trying to get the machine to boot, I had just got the Disk II's working when the video totally cut out !!. Now the machine has no display at all but it still seems to work and I can hear the machine booting and beeping as usual.
After reading a few other posts and reviewing some of the troubleshooting manuals I started to swap a few chips with the original mainboard, but I have been unable to restore the video output.
So far I have swapped the following with no luck :
a2,a3,a8,a9,a10
b1,b2,b5,b8,b10,b11,b12,b13
d11,d12,d13,d14
ram row c
Can anyone advise on any other IC's to investigate or other components to test?
Many thanks in advance.
Rich
Hi All,
I'm just bumping my post to see if anyone can offer any advice. After looking at the 'apple II circuit description book' I am starting to think that the 2N3904 transistor (Q3) maybe worth checking?
Can anyone advise?
Regards
Rich
Hi All,
Just a quick update to say that I managed to fix my original Europlus mainboard by replacing the CPU :-), so I now have a working machine. I think I'll work on getting the motherboard with the failed video working some other day.
Rich