4220 with a low left channel

[Matt Mincer]

Het folks,

I have a 4220 receiver where the left output is low. The right seems fine. I have Deoxit everything and there are no obvious problems. Any know problem areas on these? What are the TA7109 chips on the power amp board?

Thanks in advance
Matt

 

[Steven Tate]

Did you Deoxit the 2 Ch/4 Ch switch on the back of the unit? Its worth ruling out. Careful -- Power off, spray, work it many times, and blow it out good with canned air and let dry before powering up again. And never switch it while powered up. The TA7109 chips are driver IC's that drive the power transistors. They replace a handful of transistors that would have been used in earlier models.

 

[catrafter]

The circuit board that the balance controls are mounted on is frequently a problem on these. The 'griplets' or rivets that connect the traces on each side of the circuit board loose contact.

Tom

 

[mustang1102]

Het folks,

I have a 4220 receiver where the left output is low. The right seems fine. I have Deoxit everything and there are no obvious problems. Any know problem areas on these? What are the TA7109 chips on the power amp board?

Thanks in advance
Matt

Did you ever resolve the low output channel on the Marantz....? Sounds like I have the exact same issue....already disassembled and cleaned all the balance controls, the 2 Ch/4 Ch switch on the back, as well as the tape monitor switch. Still have lower output on the left channel, its there, but just a little lower than the right.

Now looking at the power switch....? Seems that the speaker outputs go through the power switch as well....? Never seen that before.