Cleaning Volume Pot on Onkyo TX-6500MKII

[Chilibrother]

The Onkyo I got at an auction a few months ago for $45 has been working perfectly, except that the right channel occasionally cuts out. If I twiddle the volume control it snaps on.
Decided it was high time to pop it open and do some cleaning. Everything is easy except (of course) the volume control. I swear that it's sealed in a gray plastic box and surrounded by circuit boards.
Not enthused about completely disassembling to deoxit one pot but . . .
Is there something obvious I've missed? (Only asking because I am old and often miss the obvious)
Thanks!

 

[NAD80]

Hello Chilibrother, Welcome to AK. Found the Service Manual at https://www.hifiengine.com/manual_library/onkyo/tx-6500.shtml. Just register and download for free if you need it. Just looked at it. The volume pot looks to be a 4 gang pot assembly based on the schematic and pcb layout. Could you post some pics of the pot? Sometimes the pot assembly is in a sealed assembly for protection. Some can be opened with a screwdriver. Don't know what's in the unit without pics. Also check for bad solder connections on the pot to the PCB.

 

[Chilibrother]

Hello Chilibrother, Welcome to AK. Found the Service Manual at https://www.hifiengine.com/manual_library/onkyo/tx-6500.shtml. Just register and download for free if you need it. Just looked at it. The volume pot looks to be a 4 gang pot assembly based on the schematic and pcb layout. Could you post some pics of the pot? Sometimes the pot assembly is in a sealed assembly for protection. Some can be opened with a screwdriver. Don't know what's in the unit without pics. Also check for bad solder connections on the pot to the PCB.

Thanks. Guess if I am going to own one of these I ought to have the service manual.
Yup. Definitely looks like a "Sealed for your Protection" component. Getting late but I'll pull the cover back off tomorrow and try to get a picture - but they really hid that sucker down in there! I'm also going to hit the speaker selector with Deoxit again. Starting to wonder if that's the actual culprit.

Appreciate the help!

 

[Goldie99]

The speaker selector switch is certainly a possibility, but it actually sounds more like a protection relay issue to me. I doubt it's related to the volume pot based on the information so far.

Next time it happens, try just tapping the relay with a chopstick or similar - if the sound returns, you need to clean or, ideally, replace the relay.

 

[waggs098]

The Onkyo I got at an auction a few months ago for $45 has been working perfectly, except that the right channel occasionally cuts out. If I twiddle the volume control it snaps on.
Decided it was high time to pop it open and do some cleaning. Everything is easy except (of course) the volume control. I swear that it's sealed in a gray plastic box and surrounded by circuit boards.
Not enthused about completely disassembling to deoxit one pot but . . .
Is there something obvious I've missed? (Only asking because I am old and often miss the obvious)
Thanks!

Do you hear any static from the speakers when you move the volume control or does it sound clean when moving it? If you hear lots of static when moving the volume it needs cleaned. If the volume works great and you don't ever hear static when moving the volume then I'd say it's clean and the issue is elsewhere.

Does the channel cut out and you have to turn the volume up and all the sudden the sound comes back to that channel and plays fine till it just cuts out again? If this is the case then I would say it's the relay also.

 

[Chilibrother]

That is exactly the symptom waggs098 I will go and work on the relay. Happily, it is much easier to access than the volume pot.
Many thanks to you and Goldie99 I never would have thought to look at the relay.

Audiokarma is a great place to be. Just wish I knew enough to help other people out.

 

[waggs098]

That is exactly the symptom waggs098 I will go and work on the relay. Happily, it is much easier to access than the volume pot.
Many thanks to you and Goldie99 I never would have thought to look at the relay.

Audiokarma is a great place to be. Just wish I knew enough to help other people out.

Your welcome.

It is possible it could be the speaker select switch but ill put all my money on the relay.

If you stay around long enough you'll gain some knowledge to help other people. Everything I know has been learned on this website. It's a great place. Still I have 1/10 of the knowledge of some of the great folks here.

 

[grillebilly]

I have tried to lube the volume control on my 6500 and 8500 and encountered the same problem. They are the stepped attenuator style. I have no idea on the proper way to service them as they appear to be sealed.
I had a channel cut out and it was the tape monitor or selector knob, which is much easier to service. I would guess 3/4 of the time a channel cuts out on any of my vintage receivers that is the culprit. I used to have to clean them about once a year but after I started lubing them with Faderlube it's one and done.
Let me know if you find out the correct way to service the volume control.

 

[KingBubba]

I have the 8500MkII, which is similar to yours. One place I had issues with the input (tape monitor) switches causing my dropouts.

You might find replacing the relay is a better choice than some of the ways to clean it. They are not very expensive.

I see grillebilly beat me to the call. If the volume controls are Alps controls, they are held together by 4 screws, one in each corner. I have cleaned that kind of control by loosening the screws just enough to not disassemble the control. This exposes cracks into which you can insert Deoxit, or other cleaner followed by lube. After that is done, then tighten the screws back and all should be good.

 

[waggs098]

I have the 8500MkII, which is similar to yours. One place I had issues with the input (tape monitor) switches causing my dropouts.

You might find replacing the relay is a better choice than some of the ways to clean it. They are not very expensive.

I see grillebilly beat me to the call. If the volume controls are Alps controls, they are held together by 4 screws, one in each corner. I have cleaned that kind of control by loosening the screws just enough to not disassemble the control. This exposes cracks into which you can insert Deoxit, or other cleaner followed by lube. After that is done, then tighten the screws back and all should be good.

Yeah the volume pot the MCS 3275 is like that. I had to do the same thing to mine. Loosening the screws just enough to get deoxit in it.

 

[Chilibrother]

I have the 8500MkII, which is similar to yours. One place I had issues with the input (tape monitor) switches causing my dropouts.

You might find replacing the relay is a better choice than some of the ways to clean it. They are not very expensive.

I see grillebilly beat me to the call. If the volume controls are Alps controls, they are held together by 4 screws, one in each corner. I have cleaned that kind of control by loosening the screws just enough to not disassemble the control. This exposes cracks into which you can insert Deoxit, or other cleaner followed by lube. After that is done, then tighten the screws back and all should be good.

Thanks. I do remember that the box says ALPS on it. I'll see if I can discern screws. Been busy today recapping some speakers. So far - running the speaker selector switch on A+B instead of A and no problems (knock on wood).

 

[Chilibrother]

I have tried to lube the volume control on my 6500 and 8500 and encountered the same problem. They are the stepped attenuator style. I have no idea on the proper way to service them as they appear to be sealed.
I had a channel cut out and it was the tape monitor or selector knob, which is much easier to service. I would guess 3/4 of the time a channel cuts out on any of my vintage receivers that is the culprit. I used to have to clean them about once a year but after I started lubing them with Faderlube it's one and done.
Let me know if you find out the correct way to service the volume control.

Thanks. I definitely need to get some Faderlube. So far I've only used the cleaner.

 

[schmikka]

Good luck - awesome receiver. I'm listening to my TX-6500 MKII now!