I want to get my old SE/30 working properly again. The screen is really dim and the picture doesn't fill the entire screen, but we have all the internal adjustment pots maxed out. Instead of buying a dead SE or SE/30 to cannibalize the screen board from, I'd like to replace the capacitors.
The capacitors are more than likely the problem, because the machine is about 20 years old. The picture tube is showing the signs of low voltage a couple general household repair books I have describe, so the caps on the analog board are more than likely the issue.
How do you measure how much capacitance capacitors still have with a multimeter? (I have a few to work with, including one of those huge "bench" ones, if that helps.)
Thanks!
Why go through the trouble? Because I think I can get it online through an Ethernet to Localtalk bridge. It will run Netscape 4, MacWeb 2, or any other time-appropriate browser and has a full 8 MB of RAM at its disposal, so why not? Just something to do on a weekend when the weather's crappy.
Measuring Capacitor Capacity?
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Measuring Capacitor Capacity?
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Remove the capacitor from the circuit (disconnect at least one side)
Multimeter: buy/borrow one that does capacitance
Oscilloscope: apply a square wave to an R/C circuit, measure the time constant graphically from the screen
I think generally though, all of the electrolytic caps should be considered 'bad', after 20 years they would have probably dried out on their own. You can visually inspect for especially terrible ones, where the top piece of aluminum has become convex instead of flat or concave. Or perhaps there is some leakage.
Multimeter: buy/borrow one that does capacitance
Oscilloscope: apply a square wave to an R/C circuit, measure the time constant graphically from the screen
I think generally though, all of the electrolytic caps should be considered 'bad', after 20 years they would have probably dried out on their own. You can visually inspect for especially terrible ones, where the top piece of aluminum has become convex instead of flat or concave. Or perhaps there is some leakage.
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