Do you have 12v on pin 1 of U8?
What is the DC voltage across U8 pins 1 and 2?
What is the DC voltage across D13?
What is the DC voltage across U8 pins 1 and 2?
What is the DC voltage across D13?
Is there any corrosion in the area?
The 12v is dropping about 12v between pin 1 of the opto-coupler and pin 14 of the inverter/buffer. There isn't anything near that across all of the series components combined. There could be a break under a capacitor.
IF you post the DC voltage (black probe on ground) for all of the terminals between opto-pin 1 and inverter pin 14, it should be easy to see the break.
The 12v is dropping about 12v between pin 1 of the opto-coupler and pin 14 of the inverter/buffer. There isn't anything near that across all of the series components combined. There could be a break under a capacitor.
IF you post the DC voltage (black probe on ground) for all of the terminals between opto-pin 1 and inverter pin 14, it should be easy to see the break.
Could D13 be defective? Maybe I measured this wrong before.
I've got 11.2VDC before and .613 after.
I've got 11.2VDC before and .613 after.
Hi perry, thank you for the help. I'm going to attempt to replace d13. I was able to measure AC voltage on the output while jumping d13.
I must have misunderstood the test you requested on this part.
Thank you for being patient, my troubleshooting skills are a bit rusty.
I must have misunderstood the test you requested on this part.
Thank you for being patient, my troubleshooting skills are a bit rusty.
Perry, I'm trying to find a suitable led replacement. Could I remove this and permanently bridge it?
Any red, green or amber LED will work. You should be able to jump it out if you don't want the indicator.
It will not be significant for the LEDs mentioned but diodes with extremely high forward voltage may not allow the mute circuit to function as it should. Try to use one with a forward voltage between approximately 1.7 and 2.2v.
Hello,
Tonight I removed D13 and bridged it.
This did not work, voltage after r54 drops to .717 when bridged
As soon as the bridge is removed the voltage comes back to 11.69
I verified this several times.
Tonight I removed D13 and bridged it.
This did not work, voltage after r54 drops to .717 when bridged
As soon as the bridge is removed the voltage comes back to 11.69
I verified this several times.
That's to be expected. What's different now from when you bridged it and the amp worked normally?
This amp never worked in my care. After I bridged it I went and tested all the same points and saw significant voltage drop, if this is normal I will put the bridge back in and test for output
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