Hi,
I have an old MC77 (v46) board from 2007 that I just installed.
I have wrong voltages coming from the PSU.
The AC voltage between each of the secondary taps to the CT is 40.01 ACV (in the schematic it's 39.3 ACV).
At the positive end of the bridge rectifier there are 48.4 DCV while at the negative end of the bridge rectifier there are -46..4 DCV.
At the cathode of the 30V Zener diode there are 31.8V
At the input of the LM337 there are -38.1V and at the output of the regulator there are -37.2V (instead of -10V).
What could cause those problems?
Any recommendations for troubleshooting this issue?
I have an old MC77 (v46) board from 2007 that I just installed.
I have wrong voltages coming from the PSU.
The AC voltage between each of the secondary taps to the CT is 40.01 ACV (in the schematic it's 39.3 ACV).
At the positive end of the bridge rectifier there are 48.4 DCV while at the negative end of the bridge rectifier there are -46..4 DCV.
At the cathode of the 30V Zener diode there are 31.8V
At the input of the LM337 there are -38.1V and at the output of the regulator there are -37.2V (instead of -10V).
What could cause those problems?
Any recommendations for troubleshooting this issue?
