Apple II: another project

["spacealbum" <dbackenkoehler@t-online.de>]

Hello from Germany,

encouraged by Nama's great project, I decided to do some research an my
dead Apple II again. I bought a II europlus as a donor and started to
swap the ICs to see if I can trace some defective ones as well
(cleaning alone didn't help)  In the end it turned out that two of them
are defective!!!
I could not test the two little 555`s though as they are souldered to
the RFI board - btw. the two ICs on the original II read 455, might
this be a problem? - and I couldn't test the two 8T28s, because Apple
changed them on the RFI board).

Changeing the two dead ICs I have the follwing situation on my Apple II
(Motherboard Rev. 800-0001-04, Monitor ROM, Integer Roms):

When I power it on, the power light on the keyboard goes on and the
computer beeps (it didn't beep before swapping the ICs). If I plug in
an autostart ROM and a disk interface, the disk drive starts to wirl
and a the computer loads the disk. If I put in a DOS 3.3 disk the
computer seems to load it, and I can reboot typing in PR#6.
But unfortunately on the screen I only see 40 horizontal bars, I can
move the corsor around in between these line, but I see no characters
;-(
After 30 seconds, the character generator ROM at A5 (that works fine on
the Plus) gets terribly hot so I have to switch of the machine.

Maybe someome out there can help me how to go on now?

Dirk