68kMLA Classic Interface

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Classic II any hope?
Posted by: CharlieFrown on 2016-07-07 10:28:31 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 ?
Posted by: bibilit on 2016-07-07 11:57:18 No chance, the only possibility will be to have a Classic available.
Posted by: CharlieFrown on 2016-07-07 12:15:48 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?
Posted by: bibilit on 2016-07-07 23:01:32 Clean the board and replace all the caps, including the ones on the AB.
Posted by: CharlieFrown on 2016-07-08 10:22:02 ok gentle tilting on analog board gave me this, from zero reaction on screen to these bars. At least CRT is working!
Posted by: Elfen on 2016-07-08 13:22:56 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!
Posted by: CharlieFrown on 2016-07-10 13:41:34 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.
Posted by: BadGoldEagle on 2016-07-10 14:06:13 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!
Posted by: Elfen on 2016-07-10 17:02:27 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.
Posted by: bibilit on 2016-07-10 23:09:58 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.
Posted by: Paralel on 2016-07-11 00:18:08 Capacitors on the Analog Board side. Bingo. Had the same issue. Had the A/B recapped. no more jutter/vibration with the monitor image.
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