Sadly, often a shorted / failing flyback. How does C1 or the top-most pin on J1 look? Any darkened / burned-looking areas?Out of curiosity.. what could cause a transistor to almost explode like this ?
Sadly, often a shorted / failing flyback. How does C1 or the top-most pin on J1 look? Any darkened / burned-looking areas?Out of curiosity.. what could cause a transistor to almost explode like this ?
Sorry to hear it... that's frustrating to be sure. Keep faith as this is a fixable problem.Time to pause this project. I replaced the transistor and the flyback transformer and still nothing.. chirp chirp chirp.
Yes. U3 brand new. Adjusted voltage from min to max with no results. Capacitors are looking very healthy, but I might have a go in a few weeks, when I find again the will to tackle this specific board hehe. If I have time I will "brute force it" and replace everything just to have the satisfaction to win this battle : )Sorry to hear it... that's frustrating to be sure. Keep faith as this is a fixable problem.
I went back through the thread and didn't notice if this was stated clearly: did you replace the electrolytic capacitors on the analog board? It could be something as simple as that.
Did you replace U3?
Also, had you at any point adjusted the voltage regulator? I have found that sometimes after replacing components the machine will start crowbarring I need to re-adjust voltage down.
Sorry to hear that. I hope you can fix it!Hello people.
Time to pause this project. I replaced the transistor and the flyback transformer and still nothing.. chirp chirp chirp. I checked all the documentation, scrolls and papers, tested the components and didn't find any other issue on the board. At this point I will wait to bump into another MacPlus and comparing the two, and maybe transplant T1 since there's no much more I can replace here.
In the meantime I want to thank all of you for your support, messages and for sharing your knowledge ... and the sacred scrolls : )
Stubborn indeed. But soon or later I will really replace everything just to get to the bottom of it. Hope to share some new knowledge on this known issue : )I'm very sorry to hear that, @Michelangelo. You have a very stubborn Analog Board!
That sounds like a lot of work!Stubborn indeed. But soon or later I will really replace everything just to get to the bottom of it. Hope to share some new knowledge on this known issue : )
Hello. Thanks for the tip but I checked continuity on all the connectors : )Please don’t forget to check the hidden fuse in the harness: