Problem with BPC's

What are you using to supply power to the control circuits inside the BPCs?  Do you have a separate 12-18V power supply?

If I understand you correctly, the A and U terminals on the BPC is connected to the output of the ZW set to 14V, which is in turn fed by a 180W brick?

What is the voltage source that is feeding the tracks?

I have 2 other 180 bricks that are powering the inside and outside tracks (A & D) handles on the same ZW.  I have a CW-80 that I think I will try and use to power the BPC's only.  Do you think that could be causing the noise?

Also isn't there a problem with polority with some CW-80's?

Thanks for your help Dale.

Doug

I tried the CW80 with no change.  One of the two BPC's buzzes and the otheris silent.

Doug

The electronics inside the BPCs would probably prefer to have a direct feed from a transformer without going through something that chops up the waveform like the ZW and CW-80 do.  Do you have a suitable wallwart?

Since one BPC works and the other buzzes, my first suspicion is that the energy storage capacitor in the power supply of the buzzing unit has gone bad or is disconnected.  If you were to open the unit, the capacitor would be obvious since it is the largest capacitor on the circuit board.

It is the big can on the right edge of the board.  I can't read the identification in this photo, but it is probably "C3".  The other possibility is a bad diode.

How old is your unit?  These capacitors can fail due to age.

The unit is probably 4-5 years old.  I think that I will need to replace it.

Doug