I have been given an old Carver amp. The power transformer has been removed, apparently for testing and was included. Transformer seems to be fine, but two diodes were found to be shorted. I replaced the diodes and repaired the pcb foil pattern (burnt from excessive current)
Now to re-install the transformer I don't know where all the secondary leads attach. I assume the yellows go to the large bridge since they reach, but the orange leads and the red leads pose a problem. Can any one help me out with which go where. Thanks for any help you can offer.
Now to re-install the transformer I don't know where all the secondary leads attach. I assume the yellows go to the large bridge since they reach, but the orange leads and the red leads pose a problem. Can any one help me out with which go where. Thanks for any help you can offer.
Hi oldsthunder,
I'll bet the triac is shorted, or there are a few other problems that can come up. The triac is used as a voltage regulator. Do not short it!!
Normally a blown output will cause the amp to cycle and "try" to turn on. The protection circuit will keep turning it off. The voltage adjust control (pot on the board running back to front) can get noisy. This adjusts the DC rail voltages and they run close to the limits on the caps. Don't "twiddle" the control!!
If you still have the old dual section capacitors on that same board you may find them open. That can cause all kinds of trouble. Stick a meter on one of the two larger caps on the bottom of the chassis. The voltage should not go over 124 VDC under any circumstances. It tends to drift up and the caps are rated at 130 VDC. I set these at 118 VDC in view of this. Power loss is minimal.
Just so you understand, the power supply top rails sit at +/- 124 VDC for a factory setting, or down to 118 VDC. That is a ton of juice! This amp will deliver all the power it is rated for, so it is not a toy. It can kill you if you give it a chance. The caps do not discharge quickly either.
-Chris
I'll bet the triac is shorted, or there are a few other problems that can come up. The triac is used as a voltage regulator. Do not short it!!
Normally a blown output will cause the amp to cycle and "try" to turn on. The protection circuit will keep turning it off. The voltage adjust control (pot on the board running back to front) can get noisy. This adjusts the DC rail voltages and they run close to the limits on the caps. Don't "twiddle" the control!!
If you still have the old dual section capacitors on that same board you may find them open. That can cause all kinds of trouble. Stick a meter on one of the two larger caps on the bottom of the chassis. The voltage should not go over 124 VDC under any circumstances. It tends to drift up and the caps are rated at 130 VDC. I set these at 118 VDC in view of this. Power loss is minimal.
Just so you understand, the power supply top rails sit at +/- 124 VDC for a factory setting, or down to 118 VDC. That is a ton of juice! This amp will deliver all the power it is rated for, so it is not a toy. It can kill you if you give it a chance. The caps do not discharge quickly either.
-Chris
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