Troubleshooting Soundstream Rubicon 6.400

[frylock11]

I took Ohm reading of all the listed transistors again.

IRZF48
Leg 1-2 230KOhm

[frylock11]

Sorry it took my post too soon

IRZF48 (8 total, they all measured about the same)
Leg 1-2 230KOhm
Leg 1-3 300Ohm
Leg 2-3 -200KOhm

TIP36CW (4 Total)
Leg 1-2 300KOhm
Leg 1-3 300KOhm
Leg 2-3 -200KOhm

TIP35C (4 Total)
Leg 1-2 150KOhm
Leg 1-3 300KOhm
Leg 2-3 225KOhm

SF104 CT (2 Total)
Leg 1-2 Between 500KOhm or it would climb to open
Leg 1-3 0.2Ohm
Leg 2-3 500KOhm

Let me know what else I should be checking, thanks

[Perry Babin]

Now start checking the smaller transistors on the board in the defective channel. If none read shorted, compare their readings to the corresponding transistors in the other channels.

[frylock11]

I ended up pulling the board out of the amp base to reach the bottom pins of the transistors because I couldn't reach them from the top. I think I have my defective section narrowed down, there is a green wire going from Channel 4 to 1 of 4 identical squares of pieces. I checked the smaller transistors(anything with 3 legs?) and none were shorting out. A few would read open between points, but they seemed to be doing that all over so I don't think that is a problem. I did not write down all the measurements I took because I'm in a hurry, I have to leave for work in a few, but nothing seemed extremely low or out of whack. I read quite a few in the 200KOhm range. I will try to get a more accurate comparison between the channels next. If those come back ok what should I check next? Resistors, Capacitors? Thanks again for all the help.

[Perry Babin]

You can check the resistors. The larger resistors sometimes fail with no visible damage. The smaller ones generally burn when they fail but you can check them to be sure.

Look for broken solder connections or anything else that could be a problem.