SE with no video

[beachycove]

I have acquired an SE that appears to start up fine from its internal HD but that has a black screen. Yes, I have tried the brightness knob. Couple of quick questions:

1. Is a pram battery by any chance needed for an SE to display video? There is mention of the need for a pram battery on the Japanese site that details probably causes and treatments for the simisimac problem in an SE/30, and I know that a Q605 / LC 475 will not run a monitor without a functional pram battery (or the workaround of flicking the on switch twice). How about an SE? This is my first encounter with the model.

2. I could narrow down the quest by testing comopnents in an SE/30 if the two are basically the same machines, but with different logic boards. So, to start with, can an SE logic board be tested in the guts of an SE/30? It's probably best to ask before risking frying something.

 

[II2II]

1. You do not need a pram battery for the display to work on an SE.

2. You can try the SE's mainboard in your working SE/30.

3. I'm fairly certain that you can use the SE/30 analog board with the SE picture tube and mainboard to see if the analog board is the problem.

4. The analog board is almost certainly the problem. I've found that a lot of them suffer from cold solder joints.

 

[tomlee59]

The most common causes of "no raster" in these compacts are:

1) Loose crt board (this is the board at the base of the crt)

2) Bad solder joints where the yoke connector attaches to the analog board.

3) Dead 3.9uF (4.7uF in some units) nonpolar electrolytic capacitor. I don't remember how it's labeled in the SE/30, but it's C1 in the 128k/512k/Plus.

4) Flyback problem (either bad solder joints, or toasted transformer).

The vast majority of these can be fixed with ease, and at low cost, so you have a good shot at getting that gem up and running soon.

There are some general notes on troubleshooting compacts at http://68kmla.org/files/classicmac2.pdf

The SE/30 isn't covered specifically, but there are enough similarities that you'll get some idea of what's involved.