Concept 2.0 troubleshooting

jskogen

New Member
I picked up a concept 2.0 receiver for 20 bucks. Lights function and all looked good. However, both tape inputs, fm section and phono section only give very quiet audio that is very distorted. I even hooked up directly to the main in to see if it was a preamo issue Same results going straight into the power section. So I think I've narrowed it down to a power section isssue, I'm just unsure what to try next to repair it. Any help would be great!
 
Welcome to AK.........
If this unit has and protect relay. Try tapping on the relay while listening . See if any change is heard in sound quality.
If both channels are effected it could also be and power supply issue.
 
Welcome to AK.........
If this unit has and protect relay. Try tapping on the relay while listening . See if any change is heard in sound quality.
If both channels are effected it could also be and power supply issue.[/QUOTE
]
Thanks for the tips, I will give that a try.
 

I tapped on the relay with no difference. What was interesting though is that when I turned off the receiver there was a noticeable increase in volume though still staticy.
 
Both A and B sound the same.

I have not yet found a service manual.
I did some more testing. I checked the transformer and that seems good. Right and left channel are both good all the way to the preamp out.

Channel A and Channel B give me sound out of the left channel. with the volume turned up, but it's very distorted/overdriven and a very low volume.

Channel A and Channel B give me a 60 cycle hum and no sound (music) when I attach the positive speaker wire.

I found a schematic. I'm thinking something on the right channel is grounding out. I'm assuming that it must be occuring before the channel A and B split since both channels show the same symptoms.
 
It's almost as if full power is going to the right channel via a hum, but no music will come through.

Any advice?
 
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