"On the posts 3 and 7, the voltage on the base of Q18 seem to conflict."
"Base of Q18 - after turning the amp, voltage jumps to minus 7v and then slowly drops". and " and 6v for the other of that resistor. Then slowly drops for both sides."
So its approximately minus 6-7v or something around this value.
Yeah there is a 1v difference but this should be only minor reading inconsistencies and how fast DMM will catch up the voltage peaks/drops.
"If you scrape between the pads of Q61 and Q62, does the fiberglass look like it's darker than it is in other locations?
Have you touched/rubbed your scope probe (DC coupling) around on the top and bottom of the board around those transistors, with the amp on to see if the trace ever moved from the reference point?"
This I would do.
I talked with the customer once again today. He stated that the amp was scorching hot around in this area (Q60-Q61-Q62). Amp has failed in a day when temperatures were over 100 degrees Fahrenheit outside. It was mounted in the trunk upside down in a black car with not much of an air circulation.
"Base of Q18 - after turning the amp, voltage jumps to minus 7v and then slowly drops". and " and 6v for the other of that resistor. Then slowly drops for both sides."
So its approximately minus 6-7v or something around this value.
Yeah there is a 1v difference but this should be only minor reading inconsistencies and how fast DMM will catch up the voltage peaks/drops.
"If you scrape between the pads of Q61 and Q62, does the fiberglass look like it's darker than it is in other locations?
Have you touched/rubbed your scope probe (DC coupling) around on the top and bottom of the board around those transistors, with the amp on to see if the trace ever moved from the reference point?"
This I would do.
I talked with the customer once again today. He stated that the amp was scorching hot around in this area (Q60-Q61-Q62). Amp has failed in a day when temperatures were over 100 degrees Fahrenheit outside. It was mounted in the trunk upside down in a black car with not much of an air circulation.