I have had two Macs, a 512K and a Plus, in storage since they failed the smoke test in a spectacular manner a few years back. I have finally learned how to solder and de-solder, so I think its time to change the analog board capacitors on both of the machines that are otherwise in good shape. I have James Wages's capacitor list, but it says it's only good for 110 V US models. Is there a list for EU-models somewhere or are they the same since they are low voltage capacitors?
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1Mind to link the resources mentioned and specify what part(s) exactly you're talking about? Like with the according schematic section?– RaffzahnFeb 12, 2019 at 19:34
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Yes sorry. I am reffering to this list and all the capacitators on the computer's analog board: retromaccast.ning.com/profiles/blogs/compact-mac-analog-board I– David TarpFeb 12, 2019 at 21:52
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not a Mac user but 1. do not forget to discharge capacitors before soldering !!! by a short-circuit ... (fried few chips this way when I forgot) as they tend to charge up with time. 2. my bet is that low voltage boards will have the same caps the only difference would be in power supply part and probably also in video if there is CRT monitor included inside case. The higher voltage Caps will be most likely be only on the input 220V side. Not sure if it is Switching or non Switching power supply ...– SpektreJun 14, 2019 at 11:36
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The capacity might be lower for 220V but the voltage must be higher (bigger than 220 so I expect 400V markings). If you use higher capacity Caps you should be fine unless its the power switching resonance circuit (you know near a coil or ferrite transformer...)– SpektreJun 14, 2019 at 11:39
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1 Answer
If you need to repair two Macintosh 220V Power/Sweep boards, #661-76214 (the power and video parts), the only likely replacement capacitor needed would be the vertical sweep (on 120V boards, that's 3.9 uF nonpolar). If that needs replacing, the vertical sweep is missing (just a horizontal stripe for video, or too-short picture even with height adjusted).
Capacitor failures were common in 2000-2006, but a ~1985 Macintosh has more likely problems elsewhere. In addition to taking EXTREME care not to crack the picture tube (not replaceable, fragile near neck connector), one needs to safely discharge the picture tube, before doing any soldering work.
If you can compare two boards that have different faults, it might be very easy to find the problems.
