I have a 200dhc amp in for repair. I replaced the following blown items.
1. powersupply FETS (12 total)
2. audio out puts (12 total)
3. powersupply caps
4. hip4080
5. tc4424
6. tlc271 (this was potted and burnt in the middle)
amp powers up fine on current.limiter. I have rail voltage on 3 outputs on each side (65v) and around (16v) on the 3 FETS beside the FETS with the rail voltage on each side.
some of the ic's are sanded to prevent seeing the part number or ID. I currently have 0.35 volts DC hm offset and cant correct it. as soon as I adjust the voltage starts going up and down but not higher than 0.8volts. does anyone have ic I'd for the following.
IC6
IC3
1. powersupply FETS (12 total)
2. audio out puts (12 total)
3. powersupply caps
4. hip4080
5. tc4424
6. tlc271 (this was potted and burnt in the middle)
amp powers up fine on current.limiter. I have rail voltage on 3 outputs on each side (65v) and around (16v) on the 3 FETS beside the FETS with the rail voltage on each side.
some of the ic's are sanded to prevent seeing the part number or ID. I currently have 0.35 volts DC hm offset and cant correct it. as soon as I adjust the voltage starts going up and down but not higher than 0.8volts. does anyone have ic I'd for the following.
IC6
IC3
hey perry should all 12 of these IRF3710Z FETS have the same voltage around 65volts? could a defective njm2901 next to the protection circuit cause the inconsistency on all 12 FETS?
Only half of the outputs will have rail voltage on their drains. The drains of the others will have rail (65v?) to rail (0v) oscillation.
What sort of inconsistency are you seeing?
Does it produce audio?
What sort of inconsistency are you seeing?
Does it produce audio?
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I am not to familiar with this amp and was thi king it acted similar to the rockford bd series for rail voltages/oscillating. but I realized this amp doesnt have a negative rail voltage. havent put audio through it. was considered with the high DC offset voltage on speaker terminals.
I see the problem, your scope is upside down.
With the same input, post the scope images on pins 5, 6 and 7 of the 4080. with the following settings.
DC coupling
5v/div for all
5us timebase for pins 5 and 6
2ms for pin 7
set the ground reference to the center line on the scope
With the same input, post the scope images on pins 5, 6 and 7 of the 4080. with the following settings.
DC coupling
5v/div for all
5us timebase for pins 5 and 6
2ms for pin 7
set the ground reference to the center line on the scope
no I was actually working on the amp while standing on my head. ha
I was able to get a square wave on pin 5 before my scope ground cam loose and touched pin 11,12,13,14 area. no the amp is blinking protection. I guessing I damaged the 4080 ic. I will order a few more today along with njm2901 ic's that i suspect is culprit.
I was able to get a square wave on pin 5 before my scope ground cam loose and touched pin 11,12,13,14 area. no the amp is blinking protection. I guessing I damaged the 4080 ic. I will order a few more today along with njm2901 ic's that i suspect is culprit.
Signal goes flat baseline. If I start to turn the gain up too high I can here a slight popping or arching.
The signal goes? Do you still have 6v of DC? Did you try increasing the signal from the source?
Do you still have a square wave on pin 5?
Do you still have a square wave on pin 5?