Weird Mac SE Video Issue

[Scott Baret]

One of the SEs in my classroom developed a sudden video problem. The entire screen turned much brighter and lighter, with white lines (very thin, about one pixel) appearing across the screen. The Mac itself was usable and the screen readable, but the computer is unsuitable for student use at this time.

Any thoughts? I am 99.9% sure this is analog board related but am not certain what exactly needs to be fixed.

 

[CC_333]

Hi,

Does turning the brightness down help alleviate the problem at all?

If not, it sounds like an analog board problem.

According to The Dead Mac Scrolls, it could be resistors R20 (100KOHM, 1/2 watt, 5%) and/or R21 (1MOHM, 1/2 watt, 5%).

It also suggests adjusting variable resistor R24 (the Cut-Off control) to see if you can compensate. If not, it looks like some kind of component lever repair is in order.

I have a spare analog board/power supply that I could give you for the cost of shipping, if that would help speed things up. Then it would be a simple board swap procedure.

c

 

[techknight]

sounds like a failure in the blanking circuit, so your getting retrace lines, or could also be cut-off related and the CRT is running wide open.

 

[Scott Baret]

I left my Dead Mac Scrolls in Pittsburgh! Sure wish I had it with me!!!

I will bring the SE home sometime this week and check out what everyone has suggested. One of my extra Classics will take its place for now.