Harman Kardon 730 phono output

[Gustercc]

So, I recently purchased a 730. Replaced all the lights. It sounds great and I'm really happy with it. it has been recapped by a local tech shop here in town (austin) approximately 5 years ago. When I called to see if they have record of the work, they said they really don't keep records for longer than 3 or 4 years ago.
All of the inputs seem to work well except one. And I have yet to be able to figure out why. Thus, I come to you guys for guidance:
Issue: The phono stage will only play out of the left speaker. There are two phono outputs on this model. I have a confirmed working Technics SL-D30 that is/was working perfectly on my previous AVR via phono pre-amp.
What I have done:
1. It happens using both phono outputs.
2. When I [press] the mono button, then sound comes out of both speakers. So, I'm assuming the phono stage board is good, no?
3. I have confirmed that this occurs whether I use speaker set A or Speaker set B.
4. Re-checked that the technics works with my old receiver.
5. I have tried pressing the other buttons to see if it will "trigger" something, but alas, nothing changes.
6. all pots and connections have been cleaned after this was discovered.

Could a wire have been crossed during the re-capp, years ago?
Any further suggestions or ideas will be greatly appreciated.

 

[Robisme]

Mono switch is after the phono board. Check transistors on phono board. Best way to troubleshoot this is to trace the signal.

Rob

 

[Blue Shadow]

Pic of the phono board?

Not going to be too hard, not much there, the input to the board through the connector, the board and the output from the board by the wires and one should find the missing channel.

 

[dlucy]

The PHONO board in the hk 730 (original condition and then naked) looks like this:

 

[dlucy]

Could a wire have been crossed during the re-capp, years ago?
Any further suggestions or ideas will be greatly appreciated.

Yes, it is easy to install an electrolytic cap the wrong way around and "lose" a channel.

The PHONO board in the 730 also connects via a... I don't know what to call it other than a "connector". That's a great place to use DeOxit.

One or more of the transistors could have gone bad.

The contacts on the selector knob's switch wafer may need some DeOxit.

 

[dlucy]

Do you still have the bright blue little tantalum caps on the PHONO board? Being something other than an electrolytic cap they may have been skipped during the recap. They can go bad, too.

 

[Spacetrain]

All of the inputs seem to work well except one. And I have yet to be able to figure out why. Thus, I come to you guys for guidance:
Issue: The phono stage will only play out of the left speaker.

I am having the same issue, only on inputs for phono 1 or 2, plays on left channel only in stereo and both channels in mono.

I have cleaned the selector wafers, tape monitor buttons, phono connector pins etc.

@Gustercc were you able to find out what was the issue?

@dlucy do you have a photo of a recapped phono board for reference.

Thanks

 

[dlucy]

@dlucy do you have a photo of a recapped phono board for reference.

Sure. Here are the before, during, and after photos: