So just solder the +pg to -pg and then power up just the power supply? I don't understand why that would be necessary since it appears that they join together in the ground plane of the amplifier board. Could you explain why it would be needed for them to be connected at both boards?
Also, when I did it (without the amp board connected) it causes the light bulb to light up.
Also, when I did it (without the amp board connected) it causes the light bulb to light up.
Here is the schematic:
Bottom bridge is connected the wrong way. -V will have a positive voltage with respect to -PGND. You might want to check the health of that 10,000uF capacitor.
discharge the capacitor with a resistor.
remove the capacitor.
Charge up the capacitor through a 10k resistor.
Measure the charge current through that resistor. When the capacitor has reached the final supply voltage, then only leakage current passes through the resistor.
Tell us that leakage current when the charge voltage has reached the capacitor maximum voltage.
remove the capacitor.
Charge up the capacitor through a 10k resistor.
Measure the charge current through that resistor. When the capacitor has reached the final supply voltage, then only leakage current passes through the resistor.
Tell us that leakage current when the charge voltage has reached the capacitor maximum voltage.
I mean the posted schematic is wrong. However the PCB doesn't seem to have this error.
You might want to check for any internal short in the transformer shorting the two secondary windings together.
Well, it looks like something blew the 10,000uf cap on the negative rail. I swapped the cap from the positive rail of the other power supply and everything is working great. There's a tiny bit of hum at low volume levels, but since it's not in it's permanent home I have plenty of time to work on the grounding and reroute wires.
Thanks to everyone for all the help. As usual, blowing something up is a heck of a learning process.
If anyone has thoughts as to what would have caused only the negative supply caps to be damaged I'd be interested.
Tom
Thanks to everyone for all the help. As usual, blowing something up is a heck of a learning process.
If anyone has thoughts as to what would have caused only the negative supply caps to be damaged I'd be interested.
Tom
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