tanaquil
Well-known member
In the recent discussion about what replacement flyback transformer to buy, uniserver suggested buying a whole SE analog board for cheap and cannibalizing parts from it. I thought this was a great idea and I have my eye on a couple of cheap items on ebay, but in the meantime, it occurred to me that I should shop the basement. I have several compact macs in varying stages of repair. (I have problems.)
One 512Ke machine was marked as non-working long, long ago. My note on it said "Analog OK, needs motherboard", so I thought I'd try pulling the analog board and using it in the Plus that is awaiting flyback surgery. But when I examined it, there were obvious signs of burning in several spots. I'm thinking "OK" was... overly optimistic.
I want to test it further, but I'm worried a bad analog board could do something to fry a good logic board - is that irrational? Can I test this in my Plus without risking the logic board?
Also, while I was at it, I spent some time with the board and the Larry Pina book, identifying the location of common components. If I understand correctly, the severe burning on my J1 connector suggests that C1 is bad, and at 35V it is below the recommended heavy-duty 100V version anyway.
When one is rehabilitating/recapping a 128/512/Plus analog board, which components should be changed as a matter of course, even if they are not bad? Is there a modern parts list somewhere? I tried using the part description in Pina's appendix to track down C1 on digikey, but I got overwhelmed. (No tantalums suitable, there were so many other possibilities I had no idea which to choose. Ceramic? Electrolytic? Surface mount? Radial?) Looked on maccaps, but there was no parts list for the Plus analog board there.
I figure this board might be a good one to practice my skills on, since it came out of a broken machine in the first place. Any advice on ordering caps and other parts welcome!
One 512Ke machine was marked as non-working long, long ago. My note on it said "Analog OK, needs motherboard", so I thought I'd try pulling the analog board and using it in the Plus that is awaiting flyback surgery. But when I examined it, there were obvious signs of burning in several spots. I'm thinking "OK" was... overly optimistic.
I want to test it further, but I'm worried a bad analog board could do something to fry a good logic board - is that irrational? Can I test this in my Plus without risking the logic board?
Also, while I was at it, I spent some time with the board and the Larry Pina book, identifying the location of common components. If I understand correctly, the severe burning on my J1 connector suggests that C1 is bad, and at 35V it is below the recommended heavy-duty 100V version anyway.
When one is rehabilitating/recapping a 128/512/Plus analog board, which components should be changed as a matter of course, even if they are not bad? Is there a modern parts list somewhere? I tried using the part description in Pina's appendix to track down C1 on digikey, but I got overwhelmed. (No tantalums suitable, there were so many other possibilities I had no idea which to choose. Ceramic? Electrolytic? Surface mount? Radial?) Looked on maccaps, but there was no parts list for the Plus analog board there.
I figure this board might be a good one to practice my skills on, since it came out of a broken machine in the first place. Any advice on ordering caps and other parts welcome!
