Carver PX1450 one channel down

[blindboybenton]

Hello all

this one is starting to try my patience a bit

It came in for protection mode on one channel. while i was testing about. I found a short across a 26.4k resistor R371
I removed the resistor, resistor fine but short to ground from Base of Q333. It turned out that the though hole plated track was touching ground though the board, as they did sit very close to each other
sorted that out by cutting the track to the base and wired the resistor from ground to base point to point
carver_px1450_px-series_rev.c_amplifier.pdf

Tested ground to base of Q333 is now at 26.4k

Turned on then R363 ( 1k) and R372 ( 1.8k) and R21 ( 10R ) went up in smoke

I have tested all semi conductors and compared to other side.I can't find any short circuits
further investigation i found R362 ( 33R) to have blown

when i switch on now R372 ( 1.8k ) goes up in smoke

While looking at the map i noticed the same place on the good channel R476 is 270R where on the faulty channel is 27.6k

If anyone has a thoughts or assistance

BBB

[g1]

Do you have a good connection from Q333 base to Q336 base?
Is Q336 base maybe also grounded by the same defect?

[blindboybenton]

Yes G1 I checked that. that's ok. I have pulled the semi conductors out the board from that area, can't find anything

[g1]

Is Q331 ok? It could account for R372 and R363 problems.

While looking at the map i noticed the same place on the good channel R476 is 270R where on the faulty channel is 27.6k

Did you verify with resistance checks in the actual circuit board? Could be a typo I suppose.