earthquake 200dhc-mark2

RockfordFIx

Member
2012-12-03 11:56 am
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
 

RockfordFIx

Member
2012-12-03 11:56 am
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.
 

RockfordFIx

Member
2012-12-03 11:56 am
this what a 60hz wave form looks like on the speaker terminals.
 

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RockfordFIx

Member
2012-12-03 11:56 am
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.