10-03-2014, 08:04 PM
Well it looks like a fully electronic instrument and that is what I wanted to know.
The pictures are telling me that is is not just an ordinary instrument with a pickup and amplifier.
It is an analogue unit with all those little PCBs connected to the keys.
The power supply was most likely not faulty when the resistor started to burn.
There are several complex PCBs in it and those power lines with the power resistors will go to the various plugs in the top of the cabinet but not the audio power amplifier as that will not have a dropper resistor in the power supply as it will have separate ones on the transistors.
I would first use a meter to check out all the wires and plugs and make sure that all the power is getting there and that none of them are frayed and short circuiting.
Then I would follow the wire from the burned resistor to the PCB it feeds and check for short circuits between the plug pins and the negative point that joins all the negatives on the capacitors.
I would expect it to power up without the burned resistor and produce sound if the head phone wires of an MP3 player are touched on the volume control. Try this test as it will rule out the audio amplifier for certain.
It does look a bit complicated for anyone whom is new to any electronics either vintage or modern.
The pictures are telling me that is is not just an ordinary instrument with a pickup and amplifier.
It is an analogue unit with all those little PCBs connected to the keys.
The power supply was most likely not faulty when the resistor started to burn.
There are several complex PCBs in it and those power lines with the power resistors will go to the various plugs in the top of the cabinet but not the audio power amplifier as that will not have a dropper resistor in the power supply as it will have separate ones on the transistors.
I would first use a meter to check out all the wires and plugs and make sure that all the power is getting there and that none of them are frayed and short circuiting.
Then I would follow the wire from the burned resistor to the PCB it feeds and check for short circuits between the plug pins and the negative point that joins all the negatives on the capacitors.
I would expect it to power up without the burned resistor and produce sound if the head phone wires of an MP3 player are touched on the volume control. Try this test as it will rule out the audio amplifier for certain.
It does look a bit complicated for anyone whom is new to any electronics either vintage or modern.
