2325 Balance Slider Bypassed - No Left Right Stereo Separation

[richardg0n]

Restoring a Marantz 2325, and the Balance Slider has no left-right separation. The volume is the same level except for the middle position, which is slightly louder. I tested with headphones on and with external speakers, and in both cases moving the balance slider potentiometer from left to right did not affect the volume output. It sounds like the balance slider has been bypassed so that it does not affect the left-right balance. See attached picks of the balance slider wiring. How can I determine if the balance slider has been bypassed? And if so, I would like to restore it to its intended purpose. See pics below.

These are the steps I have taken to troubleshoot the problem.

• Removed slider cover and used Deoxit D5 to clean tracks and contacts with a small brush; no change.
• Crossed the Main Pre RCA's in the back, and no effect on balance.
• I looked for loose or broken wires, and everything looked connected.
• Two wires from the green cable connected to the Balance slider are soldered reversed compared to the other 2325 balance sliders I have restored and connected to the Hi Pass switch on PU01. Not sure this is an issue.

 

[runningdog]

Here's some pictures of an original one I had apart today in case this helps:

 

[BOUXY]

On my 2385 the balance switch was shot and could not be repaired! Only a switch from another 2385 could be used. To use it properly the left & right side had to be soldered together until another correct switch could be found. Don't know if yours is in a similar state?

 

[richardg0n]

Here's some pictures of an original one I had apart today in case this helps:

View attachment 2915762View attachment 2915763View attachment 2915764

Thank you Runningdog for the pics.

The wiring on my unit is identical to your pics with the exception of red/white wires from green cable that connect to the hi pass filter on PU01.

I opened the balance slider again and checked continuity of all the tracks by sliding one probe along the tracks and the the other probe on the contact at the end of each track. Good continuity.

Adjusted/ raised the slider contacts that run on the tracks and no change.

Is there anything else I can clean/check?

 

[richardg0n]

On my 2385 the balance switch was shot and could not be repaired! Only a switch from another 2385 could be used. To use it properly the left & right side had to be soldered together until another correct switch could be found. Don't know if yours is in a similar state?

Hi Bouxy,
Hoping I don’t need a replacement slider. eBay prices are too high for this part. So far it’s not looking good

 

[BOUXY]

Hi Bouxy,
Hoping I don’t need a replacement slider. eBay prices are too high for this part. So far it’s not looking good

Mine needed as exact match of which only a few could be used but maybe if you are lucky many other models will work..Possibly if you now have Stereo you can wait till a cheaper part will show up! Good luck!

 

[rBuckner]

Make sure the black wires are really grounded is all I can suggest.

 

[dankik]

I opened the balance slider again and checked continuity of all the tracks by sliding one probe along the tracks and the the other probe on the contact at the end of each track. Good continuity.

I don't quite understand. When you placed one lead of an ohmmeter on the slider and the other lead one end, did the resistance change as you moved the slider? After you pass the center, I don't think the resistance will change, but the other channel will. If so, then it would seem like the slider is working and there is something else wrong.


I tried to trace the wires from the balance control using the schematic and your photos. I think this is correct. The wires from the green cable (as far as I can tell) should to the rotary switch, not the HI Filter.

 

[richardg0n]

SOLVED! Using my Heathkit Signal Tracer, After reviewing photos from @runningdog I was able to confirm the balance slider was wired correctly. I gave the balance slider a good cleaning with Deoxit D5. I then followed the signal path left/right balance signals into the pre(PE01) and then out into the Multipath board(PU01) and narrowed the issue to a specific area of the board(see pic). The signal separation was working correctly until it reached the highlighted area below. I confirmed resistors were within spec and replaced one of the original transistors with KSC1845. The signal separation problem was repaired. Thank you, AK members, for your input and photos.

 

[runningdog]

@richardg0n You're awesome! The PU01 is a physically challenging board to work on and especially to do signal tracing on.