Comet
Williams, 1985I am rebuilding a William's Comet. I came across these two capacitors and was wondering if the yellow one is a 100mf capacitor. And is there anything special about the silver T. I. Capacitor. Why is the positive marked and not the negative. Thank you,
20200211_185436 (resized).jpg20200211_185523 (resized).jpgQuoted from GL_Pinguy:was wondering if the yellow one is a 100mf capacitor
Yes it is.
Quoted from GL_Pinguy:the silver T. I. Capacitor. Why is the positive marked and not the negative.
Maybe they thought if one was marked positive, you could figure out which the negative one is ?
LTG : )
Quoted from GL_Pinguy:Why is the positive marked and not the negative.
For a period of time in the 70s-80s, the markings just weren't quite standardized.
Quoted from ForceFlow:For a period of time in the 70s-80s, the markings just weren't quite standardized.
Ya alot of older caps marked the positive leg. I've learned to always double check.
When in doubt for electrolytic polarization orientation, take you Ohm meter, and see which trace goes to ground. For polarized electrolytics, negative always goes to ground.
Quoted from ryanbrooks:For polarized electrolytics, negative always goes to ground.
This is not always true, if an electrolytic cap is used on a negative voltage power supply the positive lead will be tied the ground.
cap (resized).PNGQuoted from GL_Pinguy:I am rebuilding a William's Comet.
You need to clean up that alkaline damage before it gets worse.
If you replace C-8 and the header pins and do some clean up with vinegar and then alcohol you should be good. A straight on pic would be more helpful.
Quoted from GRUMPY:A straight on pic would be more helpful.
Here is the overhead photo, it does not look too bad. I already replaced some of the capacitors, I will try to clean the headers. I am pretty sure the plug will have to be replaced. The soldered in chip (U12) has some light corrosion on a few of the pins. The chip in the socket (U49) looks to be ok.
20200212_070622cropped (resized).jpgI have seen worse. Get the parts removed and hit it with vinegar and a brass wire brush. Rinse with alcohol and post another pic.
Quoted from GRUMPY:hit it with vinegar and a brass wire brush
I used zep toilet cleaner & it works great! OP here's a useful thread:
https://pinside.com/pinball/forum/topic/terrybs-guide-to-repairing-alkaline-battery-damage
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Ripon, WI
Wellesley, ON