This amp had blown outputs ..
I replaced the outputs and noticed Q404 and 405 getting hot within 5 secs and the amp draws excessive current ..
I removed both driver boards for the rear channels ..
With the driver boards removed Q404,405 still get hot within 4 secs and amp draws excessive current ..
Any ideas ?
I replaced the outputs and noticed Q404 and 405 getting hot within 5 secs and the amp draws excessive current ..
I removed both driver boards for the rear channels ..
With the driver boards removed Q404,405 still get hot within 4 secs and amp draws excessive current ..
Any ideas ?
I checked everything in that channel everything tests good..
With the bias pot fully counter clockwise and driver board out of circuit the outputs still get hot within 5 secs and amp draws excessive current ..
I noticed there is corrosion around the bus bars ..
Would that cause this issue or is there something else I should check ?
With the bias pot fully counter clockwise and driver board out of circuit the outputs still get hot within 5 secs and amp draws excessive current ..
I noticed there is corrosion around the bus bars ..
Would that cause this issue or is there something else I should check ?
As was previously stated, you need to install a pulldown resistor (value not critical) between leg 1 and leg 3 of each of the output transistors (one resistor per parallel group when there are parallel groups) for the channel without the driver board. Without a pulldown resistor on the gate, the gate can charge (simply by touching the gate with your fingers) and that will make the FET conduct (even after you're no longer touching the gate).
Its drawing 40 amps of current ..
I put everything back together and this is what I get ..
Q304,305 get hot within 2 secs ..
Q404 and 405'get hot also ..
I tried seeing if the bias pot in the channel that uses q404 and Q405 did anything and turning it up or down does nothing at all like it's not working ..
The channel that uses Q304,305 the bias pot also does nothing ..
With the resistors hooked up and driver board out the outputs still got hot
I put everything back together and this is what I get ..
Q304,305 get hot within 2 secs ..
Q404 and 405'get hot also ..
I tried seeing if the bias pot in the channel that uses q404 and Q405 did anything and turning it up or down does nothing at all like it's not working ..
The channel that uses Q304,305 the bias pot also does nothing ..
With the resistors hooked up and driver board out the outputs still got hot
No. Pull the gate resistors for the channels getting hot and install gate/source resistors for all FETs that you removed the gate resistors for.
If it will still draw excess current, power up through a limiter. The DC voltage across the gate and source for all FETs involved should be 0.000v. Are any higher? If so, which ones?
If it will still draw excess current, power up through a limiter. The DC voltage across the gate and source for all FETs involved should be 0.000v. Are any higher? If so, which ones?
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