Classic II any hope?

[CharlieFrown]

ok, lets see, at least no PRAM spill, need to clean motherboard first with IPA.

Is there any chance I can test this mobo with my SE/30 monitor and power supply? Can I plug it in ?

 

[bibilit]

No chance, the only  possibility will be to have a Classic available.

 

[CharlieFrown]

ok thanks for info, bibilit. After initial cleaning I turned it on. Initially nothing happened, but after several seconds of delay I could hear fan noise.

No startup sound, no reaction on screen. What would you suggest trying first?

 

[bibilit]

Clean the board and replace all the caps, including the ones on the AB.

 

[CharlieFrown]

ok gentle tilting on analog board gave me this, from zero reaction on screen to these bars. 

At least CRT is working! 

 

[Elfen]

that sounds like a cracked solder joint on the analog board.

Check the harness jack on the analog board for cracked (or dull looking) solder joints, and desolder them, clean them up and resolder with fresh flux and solder!

 

[CharlieFrown]

after complete motherboard cleaning - temporary solution just to determine if logic board is fine before recap .

My only concern right now is slight display vibration, especially during early startup and weird high pitch noise, must be the monitor related.

 

[BadGoldEagle]

Hi charlie 

Well, it's looking good. Just a couple of things to sort out now.

I got a Classic II a couple of weeks ago, and mine produces a weird high pitch noise too. I'm going to recap that thing asap.

Bibilit and I had a closer look at it, he replaced a few caps that had started to leak and the buzzing stopped for a couple of weeks. Now it's back  xx(

A full recap is in order. I think that after a recap you won't hear that sound again. At least I hope I won't hear it again afterwards... it's a horrible sound!

 

[Elfen]

Jittery video is usually the flyback transformer. And the high pitched whine too, is also the flyback transformer as well.

The second will also lead to cracked solder joints, in the harness of the yoke and logic board harness, so check on them and desolder/clean/refux/resolder as needed.

 

[bibilit]

My only concern right now is slight display vibration, especially during early startup and weird high pitch noise, must be the monitor related.

Capacitors on the Analog Board side.

 

[Paralel]

Capacitors on the Analog Board side.

Bingo. Had the same issue. Had the A/B recapped. no more jutter/vibration with the monitor image.