Treasuretronics Selectmatic SST Pro - need help repairing

On the front, I see three electrolytic capacitors. One looks damaged. The silver one under the large brown ceramic capacitor. The rest look all right based on appearance. You have on integrated circuit in a TO-5 can (that's the round silver one in the upper right of the image). See if you can read a part number from the side. It will be an LM741 or something like that. The black part that looks like a large match head just above the big brown one is a tantalum capacitor. If the machine has been dropped, it's possible that those cracks you see in it may have killed it. See if you can read the value on that one.

Now, at this point, it looks like the machine is dirty from years of use and may have some corrosion issues. When it was assembled, the flux was left on the board and that attracted sand and other particles. Moisture can cause filament corrosion to develop between metal areas so here's what you want to do.

Get a stiff paintbrush or cut one short with scissors. Use 90% alcohol to brush the flux (brown stuff) from the board. You can get 90% alcohol from a drug store. Then, use warm, soapy water and wash it with the brush again. After washing, rinse with clean water. Dry with a fluffy towel by patting it dry - not rubbing. Follow up with another brushing of alcohol and if you have a blow dryer, blow it dry from a distance. If not, blow on it to dry it.

DO NOT TURN IT ON FOR AT LEAST 24 HOURS. This is critical because there may be some moisture left on the board which could cause problems.

After you are certain it is dry, turn it on and see what happens. Good luck.

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Some Parts have a Life time.

Electrolytic caps are The Worst for that one.


All of what GD said and more.

Is there a Capacitor as one of the Controls?

Can we see that?

Is it Open Air Type.??

Aluminum Blades that go in or out of them selves?

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A golden oldie for sure. I'd love to get my hands on it to troubleshoot it for you.

It looks as if you have a cold solder joint on the speaker, for starters. I think your problem is going to wind up being wirting and/or old components.

Here's a question for you to think about seriously. Is it worth the time and expense to fix it? Sentimentality can be had by simply putting it back together and hanging on the wall of your den. For a few hundred dollars, you can have a brand new, state of the art machine. BFO technology is not very useful in this day and age where school grounds are no longer peppered with lost coins. They've been replaced by foil juice covers and pull tabs.

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		Quote:			Posted by DarylH
	Truthfully, it's less sentimental and more just to better understand how things work.

Then you are in for a bumpy but rewarding ride. You'll get plenty of help here.

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