Technics SA5470 FM stereo issue

[TechnicsRock]

My Technics SA5470 stereo radio reception has no sound on the right channel (I can hear a very low volume when I max the volume knob) . Both channels work in FM mono. Aux, tapes and phono inputs also work, both in stereo and mono.
I just replaced all the capacitors. I tested the transistors TR103 and TR104 and they are fine. Before recapping it, the FM stereo was on and off on both channels.
I will appreciate any help on how to troubleshoot it. Any information on where to look, what circuit or component to check will be helpful. Thanks.

 

[painttoad]

the FM stereo was on and off on both channels.

i'm not following this statement. elaborate on this please.

did fm stereo work on both channels before the recap?

i just woke up so excuse me if i just ain't interpreting it properly before the coffee sets in.

 

[TechnicsRock]

The FM stereo was not working properly before the recap. It was like the sound was jumping from one channel to other, back and forth. It would not play both channels at the same time in stereo mode.

 

[painttoad]

understood. i'm no help to that but now that it's clarified, maybe someone else will be.

 

[Ylli]

How is the stereo indicator lamp working?

 

[TechnicsRock]

The stereo lamp was flashing and dull. I was able to solve both issues. First, the unstable stereo FM signal was resolved by recapping the entire unit. The problem was likely related to a bad cap on the tuner board. The stereo lamp stopped blinking and is now bright orange. The absent/weak sound on the right channel was related to a bad contact of one of the new film capacitors on the main board. I was able to track down the problem by using the schematics and comparing the voltage component by component on the right and left circuits. Thanks you all for reading and trying to help.

 

[TechnicsRock]

I was also able to realign the FM without an oscilloscope and a signal generator, with pretty good results. If you are interested, I can provide more details.