68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.

No image in Apple IIc Monitor

Posted by: Roberto on 2024-09-04 01:36:35 Hi guys. After realizing that my Apple IIc has some RAM chips to change (I have an open thread here for this very reason), I realized that its original green phosphor monitor also has some problems. The monitor is a product intended for European use, so it works with 220V. I'm sure that the monitor is not working, this is because I tried the Apple IIc (with the same video cable), on another monitor and it works. When I turned it on, at the beginning, I could hear a noise like electrical discharges. I cleaned the suction cup that is connected to the hole of the CRT (with due precautions) and now those electrical discharges are no longer heard. The green LED on the bottom right is on. Changing the contrast and brightness knobs does not show anything on the video (you should at least see the screen all green at maximum brightness). As soon as I turn off the monitor I see the classic shutdown flash on the video (so the CRT is powered). I attach some photos below to help you understand what model it is (I don't know if there are many versions of this monitor). Any advice?

Posted by: bibilit on 2024-09-04 05:28:51 Nothing obvious, maybe a bad solder joint in the connector side.

Posted by: Roberto on 2024-09-11 02:13:12 When I turned off the monitor, I noticed a strange shape of the light point in the video, so I immediately thought of a vertical deflection problem. I searched a bit in the monitor's electrical diagram (actually I just followed the tracks of the trimmer that deals with the vertical dimension) and I ended up in the AN5763 integrated circuit. So I changed it and now it can be seen well. I thought I'd write it here in case someone should have the same problem.

1