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dumb question volts/amps - how much is too much?

Ouch! Hmm ... depending on just how it was failing, that might even have worked. If the forward resistance was increasing as it cooked, then the new one would limit the voltage in the forward direction, so it might cook more slowly. But if the reverse resistance was decreasing, it would do no good at all. I never actually took the time to analyze the failure mode of the few I saw die -- just took off power and replaced them as quickly as possible. :-)

I do have one (probably still good) which came out of the base of a small Sanford surface grinder to power the mag chuck. It also had an electrolytic capacitor which was *supposed* to be 8 uF, but was closer to 0.002 uF when measured. I replaced it with a much bigger HV electrolytic, and a silicon bridge rectifier (and a redesign of the switching circuitry) to maximize the holding capacity of the mag chuck -- before I replaced it with a permanent magnet chuck.

Enjoy, DoN.

Reply to
DoN. Nichols
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The failing rectifier had smoke and flames coming out of it, so most likely it was shorting out. A lot of electrolytics were known to explode when a rectifier failed that way. They get really steamed when they have to carry high AC current. :)

I have replaced full wave selenium rectifiers with full wave silicon bridge rectifiers when they had marginal output to start with. You gained a couple volts on a 12 volt supply which was fine, since the equipment was designed to run in a car or truck. Like the little Sony

4" TV's built in the early to mid '60s. The last one of those I had with the original rectifier went up in flames while I was watching the TV. I was sick, in bed and had just woke as they announced Regan being shot when the flames started pouring through the vents in the steel case. Luckily, there were no screws in the case, and I managed to remove it before it burnt off the paint. :)
Reply to
Michael A. Terrell

Sure, but other than that loud whistling noise, it's mostly harmless. :)

Reply to
Michael A. Terrell

Unfortunately, I'm currently kind of transportation-impaired, i.e. no car, only the bus and bike, neither of which goes to Bakersfield. )-;

If it was, like, Cerritos or Montebello, I could probably bum a ride, but I don't think any of the guys wants to make a whole day trip. )-;

Thanks, Rich

Reply to
Rich Grise

Two that I can't find at a reasonable price are Perry Rhodan 122 &

124.

I am still compiling the list of missing Start trek, and lists of the duplicates in both groups.

BTW, I found a few more copies of that '70s 'Antiwar Protester's Handbook' you wanted. I can't beleive they were so gullible!

The inventory will be posted here when I finish it:

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Reply to
Michael A. Terrell

Gunner Asch on Wed, 27 Apr 2011 11:10:10 -0700 typed in rec.crafts.metalworking the following:

Thanks, this proved useful, at least for the data. Now to go home and try it.

Reply to
pyotr filipivich

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