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Thread: Pyramid Gold Power Supply Goes Out

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    Pyramid Gold Power Supply Goes Out

    Still sorting through the huge pile of stuff I got from this guy, and have a question about this power supply. If anybody knows how to work on these things and can help me out I'd appreciate it.

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    The first thing to look for is the one or two (maybe three) large transistors mounted to the heatsink. These would be the regulators, basically a large high current transistors. They will have some silicone and mica wafer between the heatsink and regulator body. Depending on circuit design you may be able to find the bad one (or more) with a simple diode check otherwise you have to remove them from the circuit to test their condition. Some just use heat sink compound instead of the wafer but both can break down, especially the silcone & wafer combo.

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    If I put my volt meter on ohms/tone, should I get a tone when touching the posts on the regulators, like I would if I put the posts on either end of a good fuse? I don't, on either of the two.

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    Normally, transistor junctions should read conductive one way and open the other way. A transisitor is just a three legged diode. A visual inspection might even reveal some indications of which regulator got hot by looking at the solder joints and the heat sink area for those sighs and chack those suspect ones first. If results are not clear, the reglators will need to be removed from the circuit and chaecked individually.

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    In my opinion, the 80 Amp Gold Series is the only good pyramid power supplies. All the other throw out so much RF it get's into you audio and radio and makes sound like shit. The Gold Series of the Pyramid is the only good ones because came with extra protection for RF leakage out of power supply. Presently only new in the Gold Series line being sold is the 80 Amp, that would compare with the best which everyone know is the Astron's.

    PS - If you get your hands on some of the older gold series could save money and get a great power supply. Did many testing of power supplies with handheld RF Meters outside to read the Leakage.
    RCI-2950DX, 1978 Cobra 148 GTL Taiwan, SHURE526T MIC, Tug-8 With Astatic 10 DA Head, Astatic 575M6, ASTRON 70/20 AMP POWER SUPPLIES, IMAX 2000 W GROUND PLANE KIT. TIMES MICROWAVE LMR-400 COAX, RF CHOKES. DIAMOND SWR/POWER INLINE METER. 250 of Sea Level Under Me. Recent World Radio Member.

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    Quote Originally Posted by Gerowen View Post
    Still sorting through the huge pile of stuff I got from this guy, and have a question about this power supply. If anybody knows how to work on these things and can help me out I'd appreciate it.
    Where's the video?
    All answers are opinions and may, or may not be technically correct.

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