soundstream rubicon 1002 no audio out right channel clip light

[ivkata]

hello i got this amp over ebay.the seller(lier) said one channel was working one was out ,but when i got it the story is diferend,when power is applied the amp will light both channel clip lights and the one for the right channel stays on.there is no voltage on both speaker outputs.when i tested for for gate power on the power fets i get 1.6v im guessing thats too little.Pcb is mint nothing looks /smells burn

[Perry Babin]

What is the rail voltage on the center legs of the output transistors (both positive and negative)?

What is the positive and negative voltage on the power supply pins of the various op-amps?

[ivkata]

outputs have rail of - + 45 volts.the op amp in the power supply is getting -+ 15 volts and im getting -13v on the Out 1.is there any thermoresistor on this am and where????

[Perry Babin]

Earlier you stated that there was no DC on the outputs (speaker output terminals?). Above you state that there is 13v on out 1. Please clarify.

There should be two thermal switches under the board.

[ivkata]

there is rail voltage of 45 on the outputs ,no current on the speaker terminals .There is small op amp in the power supply tl072cp and im getting negative 13 volts on the out1 leg 1 i believe.Im wondering if a thermal switch might be causing this ,due to clip light on the Right channel is on all the time regardless of gain level and rca conected or not.Sorry Perry my english is not soo good in terminology

[AKHeathen]

hey perry, so i have this amp now. just to clarify, there is no dc on the outputs. there is one ts i can see. rail voltages idle great at +/-48v not sure where he is getting the -13v. in the pre-amp section, both right and left circuits have identical voltages on both pairs of ic's. i really need a schematic for this amp. I've been trying to go off a 1000s, which has similar circuits, but not the same, lol. i am also having trouble trying to find any info on the driver board ic. it's marked as a c3381 in all the soundstreams i have (rub1002;1000s/sx/500s/sx, etc) yet my scematic shows a 2sc3067, and only shows 6 of the 7legs in the circuit, and the problem amp(rt channel) is showing -9.98v on that 7th leg, where the left shows -.024. i traced it across a small cap to the main board connection with -10.07, so i'll pop the board off tomorrow to trace the circuit, but i'm really just shooting in the dark without a valid schem, or help. please and thank you.

[AKHeathen]

oh, i just went and re-read the thread posts. that little op-amp is in the power supply section. both tl074cn's u-104/105 are getting +/- 17.75v. u102/103(ne5534ap) &u101(ne5532p) also +/-17.75

[1moreamp]

The rail voltages your reading are correct according to my info I have on hand. But no output on both channels is puzzling since it appears that only one channel has issues.
The FEB boards are both muted by the TLO72 op-amp in the supply and it does have input for the 17 volt signal input along with being power by those same rails.
I don't have the FEB board info and it is slightly different from the older FEB boards. But I do have a new one here I got from Jaime. Let me know what you find, You have my curiosity with the muted channels issue.

[AKHeathen]

gee-golly, you're right. i see it now. i just chocked that up to the power supply. now that i can see the whole section, there's much more, and even found the 2nd ts hiding under the inductor. i'm going to take some more readings before pulling the board. i feel stoop-id, lol. thanks bud. i could still use a rubicon 1002/702/502 sch. if anyone has it.

[AKHeathen]

got her going flawless and efficient. sounds real nice. just to update for others. traced all the circuits. i was trying to track down the source of power in the overload from the ic in the rt power driver board. just as i was warming up the iron, i looked real close, and almost could not see the broken connections. put my probes on it and sure enough, it had a few not passing any continuity. iirc, it was the rail common and enable traces. not sure which others. replaced the solder, along with a plethora of dry/ugly connections all over the board, and problem solved. thanks for the help.
-Heath H-