Based on the DC voltages, you have drive from IC3. If you have an oscope, take a look at IC2 pin 5-triangle wave, Pins 9&10-Drive and IC3 Pins 3 & 8-rectangular wave with 50% duty cycle.Use power ground for scope ground. Post screen shots.
Otherwise, replace R68 and mosfets. Check the gate resistors R117,118-33 ohm. Also, with everything in place with an ohmmeter measure between all three pins of the mosfets including output mosfets. If there are no shorted devices, power the amp and check the DC voltages around the IC2 & IC3 as you did before.
It's possible the amp is producing rails and there is a problem elsewhere.You will see the rail/DC voltages across the 2200uf/50v caps, black probe to power ground, C76,C78-positive rail, C77,C79-negative rail. Both should be ~35v? Not sure of absolute value.
Also check the =/- 17 volt rails. Q16-(-17v) Q18-(17v) and on either side of R10 & R14-10 ohm resistors.
Otherwise, replace R68 and mosfets. Check the gate resistors R117,118-33 ohm. Also, with everything in place with an ohmmeter measure between all three pins of the mosfets including output mosfets. If there are no shorted devices, power the amp and check the DC voltages around the IC2 & IC3 as you did before.
It's possible the amp is producing rails and there is a problem elsewhere.You will see the rail/DC voltages across the 2200uf/50v caps, black probe to power ground, C76,C78-positive rail, C77,C79-negative rail. Both should be ~35v? Not sure of absolute value.
Also check the =/- 17 volt rails. Q16-(-17v) Q18-(17v) and on either side of R10 & R14-10 ohm resistors.
Sorry for the delay, I have been dealing with FMLA paperwork with my HR as my wife is sick and I have been taking her to the doctors for tests 3-4 days a week since Mardi Gras. That and most of my tools are back at home 3 hours away, so I only have access to them on the weekend.
On the bright side... The amp is WORKING!!! I'm not sure what fixed it, but after I put all the parts removed for testing back in to get the next readings, the green light came on. I proceeded to connect up a sub and my ipad as input. Lo and behold it worked. I let it run for a about 20 minutes and the chassis got warm, but the unit seems to be fixed.
THANK YOU for helping me learn the basic starting points for repairing an amp.
Now to fix my US Acoustics 2050 that I used too big of an iron on when trying to install a BB OPA2132 and peeled the traces that are super thin. (didnt know it was a ZED amp at the time or what that meant. I thought it was just some cheap amp that came with a 240z I bought back in 1997 and I removed the amp immediately to install a Kicker ZR240.
Thought I had fixed it, but one channel was super loud and after a few seconds the resistor next to the speaker output started smoking and burnt out. I will create a new post for that amp when I get few pictures to share.
On the bright side... The amp is WORKING!!! I'm not sure what fixed it, but after I put all the parts removed for testing back in to get the next readings, the green light came on. I proceeded to connect up a sub and my ipad as input. Lo and behold it worked. I let it run for a about 20 minutes and the chassis got warm, but the unit seems to be fixed.
THANK YOU for helping me learn the basic starting points for repairing an amp.
Now to fix my US Acoustics 2050 that I used too big of an iron on when trying to install a BB OPA2132 and peeled the traces that are super thin. (didnt know it was a ZED amp at the time or what that meant. I thought it was just some cheap amp that came with a 240z I bought back in 1997 and I removed the amp immediately to install a Kicker ZR240.
Thought I had fixed it, but one channel was super loud and after a few seconds the resistor next to the speaker output started smoking and burnt out. I will create a new post for that amp when I get few pictures to share.
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