DCP going south??

[WOPL Sniffer]

MY thoughts exactly. Always nice to have a spare or 4 to swap in and out or to experiment with.

 

[laatsch55]

Yep, once ya hear one, ya don't wanna be without one ...

 

[roccus]

Yep, once ya hear one, ya don't wanna be without one ...

thats for sure! when it was running good I liked it better even the the carver TFM 55 I had and I always felt that was the nicest amp I had ever had till I heard the wopl

 

[roccus]

Pulled the outputs on the right channel to test.. for some reason my transistor tester does not recognize this transistors so I just used my ohm meter by putting the leads to the pins to get a reading then swapped the leads to get another reading and here is what I got...

The first row I tested are marked MJ21195G (closest to the speaker out terminals) starting with the top going down the row

1 - .68 - .68 ohm
2 - .49 - .50 ohm
3 - OL - 2.74 m ohm
4 - OL - 2.74 m ohm

The second row marked MJ21196G starting with the top one going down

1 - 170.52 - 176.45 ohm
2 - .58 - .58 ohm
3 - .61 - .62 ohm
4 - OL - 2.81 m ohm

I'm gonna go pull the left channel ones now to check out

 

[roccus]

Left channel output tests

3rd row marked MJ21195G from top

1 - OL - 2.73 m ohm
2 - OL - 2.71 m ohm
3 - OL - 2.71 m ohm
4 - OL - 2.70 m ohm

4th row marked MJ21196G (row closest to transformer) from the top

1 - OL - 2.81 m ohm
2 - OL - 2.84 m ohm
3 - OL - 2.71 m ohm
4 - OL - 2.82 m ohm

I'm not an expert but to me looks like all are OK on left channel but on right channel 2 - MJ21195G are blown and 3 - MJ21196G are junk....

 

[laatsch55]

What happened to diode check mode? In circuit resistance checks don't mean much, and after a disaster i'd pull em and check out of circuit in diode check mode....

 

[Billboard]

Looks like just about everything on the right side is junk, replace it all, keep the two or three that test good for emergency spares.

I usually mark the bad ones with an X so they do not get accidentally installed anywhere.

 

[Billboard]

Before you install the new transistors replace the known bad parts, power on with DBT check voltages........do not install drivers or outputs until all voltages are good. Then one row at a time.

 

[roccus]

What happened to diode check mode? In circuit resistance checks don't mean much, and after a disaster i'd pull em and check out of circuit in diode check mode....

Hi Lee as stated I pulled them out these tests are with the transistors out of circuit they are laying on my bench...

 

[laatsch55]

My bad, continue on, but didode check mode is better than a resistance check...

 

[roccus]

Before you install the new transistors replace the known bad parts, power on with DBT check voltages........do not install drivers or outputs until all voltages are good. Then one row at a time.

I understand.... I am back to square 1 with this amp