This is the circuit I am working on. It is a guitar Digital Signal Processing preamp. The unit has two independent set of outputs (stereo sets). OUTPUT 1 which has both XLR and RCA jacks and OUTPUT 2.
The problem is that the OUTPUT 1, is not working on the left channel both on the XLR and the unbalanced out jacks.
I did a few tests with my multimeter.
D4 and D16 on their bottom sides are short circuited between each other (they correspond to the channel that doesn't work), whereas D13 and D16 don't behave like that. D4 doesn't measure like a diode while ON the circuit. Its equivalent D16 which is on the right channel that works like a diode while ON the circuit.
The exact same symptoms I notice on D10 and D8 whereas everything seems normal on D20 and D19.
Also the bottom sides of C280 and C270 are short circuited between them. There is an equivalent set of capacitors on the RIGHT channel on the XLR output which cannot be seen on the picture, but the bottom sides of those caps are not short circuited between them.
Unfortunately I do not have the schematics for the unit , nor are they available.
Any ideas on how to troubleshoot further since there are no schematics available.
Unfortunately the company is located too far away to be able to ship there for repair.
The problem is that the OUTPUT 1, is not working on the left channel both on the XLR and the unbalanced out jacks.
I did a few tests with my multimeter.
D4 and D16 on their bottom sides are short circuited between each other (they correspond to the channel that doesn't work), whereas D13 and D16 don't behave like that. D4 doesn't measure like a diode while ON the circuit. Its equivalent D16 which is on the right channel that works like a diode while ON the circuit.
The exact same symptoms I notice on D10 and D8 whereas everything seems normal on D20 and D19.
Also the bottom sides of C280 and C270 are short circuited between them. There is an equivalent set of capacitors on the RIGHT channel on the XLR output which cannot be seen on the picture, but the bottom sides of those caps are not short circuited between them.
Unfortunately I do not have the schematics for the unit , nor are they available.
Any ideas on how to troubleshoot further since there are no schematics available.
Unfortunately the company is located too far away to be able to ship there for repair.