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  • power cap polarity

    I'm a newbie here, and kind of a newbie in general. I have two Peavey Butchers that I have used lightly for over 10 years, without servicing. They both sound identical, and have worked well the whole time. I have them both open on the bench, to clean the pots and put new tubes in. I’m looking at the amps at the same angle as the schematic. On the power board, the schematic shows the four 100uf-350v caps, and the cap below it, 1000uf-50v (caps C21,C22,C23,C24, and C28), pointing to the right. My amps have identical power boards. One of my amps has the caps pointing to the left. This one has Peavey tubes in it, so maybe it left the factory that way. I thought cap polarity was a big deal. So, it doesn’t matter so much afterall?

  • #2
    No, if you reverse the caps, you will blow fuses and destroy the caps. It matters a great deal.

    What do you mean "pointing to the right?"

    Those five caps should have their + ends on the righthand side. Typically that means the end with the insulator in it, the negative end being the end where the aluminum can is exposed. The label on the cap might on one brand show a + sign near the + end. Other brands identify the negative end, often with a stipe down the side with - signs every so often. Those of course would point to the left.

    If you are looking at which way any text on them reads, well, that has nothing to do with it. The cap makers can print on then any way they like.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      power cap polarity

      Thanks for your reply, Enzo. (I was going by the ->->-> arrows, I'm just a rookie). Going by the black and aluminum ends, the one with Peavey tubes is the one that's correct (which makes more sense). It is the other amp that is wrong! On amp #2, the 5 cap's are black on the left end, and the aluminum exposed on the right end. It looks like the previous owner had some problems with it. A resistor(R55) and diode(CR7) have been replaced. They used a 470 ohm resistor, and it should be a 4.7k ohms.

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      • #4
        I pulled the power board out. Although the components are laid out the same, the etching underneath is not the same as the PC board diagram with the schematic. I put new power caps in, replaced the resistor, put new tubes in, and cleaned the pots. The amp is working well. Thanks.

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