Pilgrimstad
New Member
Hello, I really need help now. Long story short, got a friends reciever in for a checkup because it sounded low and had a lot of distortion on left channel. A good cleaning, and I was ready to check everything according to service manual.
Problem was that I could not set line current on left channel, supposed to be 25mV could only get it up to 1.7mV, so I started checking transistors. Found one bad, replaced all of the power amp transistors with new ones from a local supplier.
Line current was now adjustable, set both channels to 25mV let it idle for approx 20 minutes, rechecked and adjusted again. All good, time to play som music. Put a record on and discovered that left channel is now free from distortion, volume is stil very low though, right channel is loud and clear. Switched to AUX, same problem.
The searching for the fault continued, and I found another bad transistor in the pre-amp, so I changed all four to new ones.
Another test, same fault on both PHONO and AUX.... this is when I switch to FM and discovers that it sounds loud and clear on both channels when playing FM.... switches back to AUX and its still low on left...
Accidentaly depresses the MONO switch when on AUX and its loud and clear from both channels, I am really scratching my head here guys.
I have measured all the voltages on different test points stated on the drawings in the manual, they all checkout fine.
PLEASE, help a poor guy out with some ideas here...
Problem was that I could not set line current on left channel, supposed to be 25mV could only get it up to 1.7mV, so I started checking transistors. Found one bad, replaced all of the power amp transistors with new ones from a local supplier.
Line current was now adjustable, set both channels to 25mV let it idle for approx 20 minutes, rechecked and adjusted again. All good, time to play som music. Put a record on and discovered that left channel is now free from distortion, volume is stil very low though, right channel is loud and clear. Switched to AUX, same problem.
The searching for the fault continued, and I found another bad transistor in the pre-amp, so I changed all four to new ones.
Another test, same fault on both PHONO and AUX.... this is when I switch to FM and discovers that it sounds loud and clear on both channels when playing FM.... switches back to AUX and its still low on left...
Accidentaly depresses the MONO switch when on AUX and its loud and clear from both channels, I am really scratching my head here guys.
I have measured all the voltages on different test points stated on the drawings in the manual, they all checkout fine.
PLEASE, help a poor guy out with some ideas here...
you could also check for bad solderjoints on the RCA jacks.and while at it, try cleaning them too.
