Mac +

[josephdaniel]

I am not quite shure where this should be posted but since I am having trouble with the monitor I guess I will put it here.
The monitor worked fine when I was using it one evening I turned it off and went to bed and came back the next morning to finish. When I turned it on I got this. Mind you that this computer was in a shed at the time in the middle of winder it was about 50 outside. So what do you guys think is wrong? My guess is a burnt resistor somewhere and ignore the lines that go from the bottom to the top that's just from my camera being out of sink. And also the screen is not near this bright when in person.
Here is the pic
http://m.flickr.com/#/photos/86449860@N03/7919299096/

[Electronic M]

That is definitely a horizontal circuit issue. Solid state electronics are far from my forte, but I'd look for lytics with bulging cans, and smoked resistors first....If that shows nothing go through those parts in the horizontal stage with test equipment. Make sure the resistors are within rated tolerance, and the capacitors check good for value, ESR, and leakage.

And listen to anyone who seems to know more than me as they probably will be able to get you more directly to cause of the issue.

[jr_tech]

The first thing that I would do is re-solder all of the connections around the flyback xformer, horz output transistor(s?) and damper diode, as these connections tend to unsolder themselves over time. I have not had mine apart in over 15 years, when I replaced a failed damper diode with a better (faster) part, and re-soldered a bunch of connections.

jr

[sweitzel]

Mac + analog boards were notorious for cracked/cold solder joints on the PCB. I used to rebuild those boards for schools years ago. Be careful disconnecting the HV from the flyback to the CRT. You need to discharge through a high value resistor to avoid damaging the main control IC on that board.

[ha1156w]

Agreed. They were notoriously unreliable even when new due to capacitors that weren't heat-rated (85C vs 105C I think) plus weak solder joints that go flaky over time. Jobs' obsession for not having a fan in it made for a marginal performance. There's a book out there - Macintosh Repair and Upgrade Secrets (Larry Pena, ISBN 0-672-48452-8) which details multiple changes to component ratings and values to significantly improve performance. That books is considered the must-have reference for the original 9-inch Macs.

[compu_85]

One of these days I'll have to bring my Lisa back to VA with me and do some diagnosis on the video circuit... when you adjust the horizontal phase first every even raster line moves, then every odd raster line. It can be adjusted to give a good picture, until the machine warms up and then it drifts a tad... very annoying.

Another problem relates to how bright the picture is... whenever something dark is displayed on the screen the size of the picture shrinks, everything gets a tad out of focus, and everything gets darker. Like the early Macs the screen is white with black text so normally the picture looks fine, but in the terminal program or if you draw a black square in a drawing document it's rather annoying.

I've replaced the caps in the PSU and video board, but haven't done much actual diagnosis yet. It does have a NOS CRT installed

-Jason