I have an Apple IIc monitor that only displays 3/4 of the screen.
The right 1/3 of the display fades.
This monitor was like this when I acquired it about 5 years.
No amount of adjustment helps apart from turning up the brightness.
Further, I don't have the circuit diagram.
Please see the attached photo of the screen.
Does anyone have any idea of where to look for the fault, or what the
fault might be? I suspect the horizontal deflection circuitry but would
appreciate advice before powering up the soldering iron.
[img]http://www.applefritter.com/files/images/partial%20IIc%20screen_1.preview.JPG
There is a SAMS technical service manual available online which may assist you. I found there are some minor differences compared to the Australian delivered versions I have but it's still very useful.
If you can't find it let me know and I'll email it to you.
Cheers!
Thanks Dc99,
I've one of the SAMS books for a IIe only. I cannot locate the one you refer to.
Would you be kind enough to email it?
Perhaps PM me and I can give you my google email address?
Thanks,
Laurie
http://apple2online.com/web_documents/Sam's%20Apple%20IIc%20Monitor%20KB.pdf
good possibility is the power supply off the flyback that feeds the CRT
has a bad cap like C517. The ripple is at the horizontal rate which produces the vertical dark band
Larry G