Synthesizer dead

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The fuse in this unit was dead. I replaced the fuse and it still wont power up. I am desparate for help with this. I have noticed that the pins of the output opamps have 3.42 volts on pins that should not have power. The Vcc and ground of the opamps are correct. I know the opamps are not power related but I am wondering if this is an indicator of another problem
Thanks
 

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The fuse in this unit was dead. I replaced the fuse and it still wont power up. I am desparate for help with this. I have noticed that the pins of the output opamps have 3.42 volts on pins that should not have power. The Vcc and ground of the opamps are correct. I know the opamps are not power related but I am wondering if this is an indicator of another problem
Thanks
That's about half of 7volts, so correct.
The 5volt chopped power supply has the issue. Check the MosFet is oscillating and chopping the DC to induce the desired output voltage, via the winding and clamping diode.
 
This helps a great deal except that it is beyond my understanding. The 5 volt and 7 volt appear ok. I also noticed that a set of 5 volt opamps have 1/2 of their operating voltage on in and out pins. Could you please help me to try to understand the path of the leaking voltage.
I am reluctant to send my board for repair. I believe the "experts" will tell me that my mainboard is defective.
 
One thing you can do: test if the oscillator is working. You can check it on IC14 pin 2. If you don't have an oscilloscope, a DMM in 20V AC setting will do.
The question is what caused the fuse blown out, and why it wouldn't happened again after you have replaced it. I suppose you replaced it with the same rating. Power surge?
 
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