[ChevyMonsenhor]

My main amplifier (for both headphones and speakers) is a vintage Onkyo A-817XD integrated amp from 1988 which i believe was never revised by its previous owner(s).
Recently i noticed that when i allow the tonal controls on it to function (the only way the amp allows the balance control to be used) the sound coming out of it is slightly attenuated to the left and i have to correct it by turning the balance knob some 10% of a turn to the right, which wasn't needed before.
I know the problem is tied to the potentiometer itself because when i turn on the "Tone Defeat" option, which ignores the balance pot, it sounds 100% centered.
Is there any way i can fix this without changing the potentiometer itself?
And considering the fact that this is a older device, if i do need to change the potentiometer itself, would it be a good idea to change the capacitors as well?

 

[tomb]

Well, going from loosening the nut on the potentiometer and re-tightening it on center, to changing capacitors is a giant leap. Is any Onkyo old enough to have a cap change? I didn't even see the brand name until the 90's.

Go find the service manual here: https://www.hifiengine.com/hfe_downloads/index.php?onkyo/onkyo_a-8170_service .pdf

You may need to create an account on hifiengine.com if you don't have one. They won't let you download manuals unless you have a user account. However, there's an exploded diagram that should let you figure out how to dis-assemble the amp. From the diagram, it looks like there's a false front behind the face plate - that's where the balance potentiometer is mounted. You'll probably need to remove the top and sides (typically one piece). Usually, you remove the side screws, then there's a few connected to the lid/sides from the back plate. Once those are removed, you should be able to swing the lid/sides out of the way. From there, look to see how the face plate is attached and remove it. You'll probably have to remove all the knobs. Be careful and figure out for each one whether they're push-on or set-screws. EDIT: looks like they're all push-on. Once that's done, you should be able to get to the pot and re-center/tighten it.

 

[ChevyMonsenhor]

Well, going from loosening the nut on the potentiometer and re-tightening it on center, to changing capacitors is a giant leap. Is any Onkyo old enough to have a cap change? I didn't even see the brand name until the 90's.

Go find the service manual here: https://www.hifiengine.com/hfe_downloads/index.php?onkyo/onkyo_a-8170_service .pdf

You may need to create an account on hifiengine.com if you don't have one. They won't let you download manuals unless you have a user account. However, there's an exploded diagram that should let you figure out how to dis-assemble the amp. From the diagram, it looks like there's a false front behind the face plate - that's where the balance potentiometer is mounted. You'll probably need to remove the top and sides (typically one piece). Usually, you remove the side screws, then there's a few connected to the lid/sides from the back plate. Once those are removed, you should be able to swing the lid/sides out of the way. From there, look to see how the face plate is attached and remove it. You'll probably have to remove all the knobs. Be careful and figure out for each one whether they're push-on or set-screws. EDIT: looks like they're all push-on. Once that's done, you should be able to get to the pot and re-center/tighten it.

Thanks a lot for the manual, its going to be of great use!
I should've mentioned however that this pot already has a fixed center on it, its not dictated by just the knob, it itself has a set central position and it seems to be slightly off.

 

[tomb]

Thanks a lot for the manual, its going to be of great use!
I should've mentioned however that this pot already has a fixed center on it, its not dictated by just the knob, it itself has a set central position and it seems to be slightly off.

Unfortunately, that may be difficult. If a pot has a center detent like that, it's usually in a shorting mode. So, the channel imbalance is probably occurring elsewhere. Balance, tone, and switching controls in a pre-amp section often go through other resistors and capacitors. One or several of those may have "drifted" over the years and could be causing the imbalance. I've often found them slightly off compared to switching them out of the circuit, if that capability is available. It might even be worse if you change out the pot. You are better off switching the entire section out of the circuit, for the best sound, as you've apparently been doing.

I'm still just guessing, though. If you can find a pot replacement and it seems easy enough to change, you could try it and see.

 

[ChevyMonsenhor]

Unfortunately, that may be difficult. If a pot has a center detent like that, it's usually in a shorting mode. So, the channel imbalance is probably occurring elsewhere. Balance, tone, and switching controls in a pre-amp section often go through other resistors and capacitors. One or several of those may have "drifted" over the years and could be causing the imbalance. I've often found them slightly off compared to switching them out of the circuit, if that capability is available. It might even be worse if you change out the pot. You are better off switching the entire section out of the circuit, for the best sound, as you've apparently been doing.

I'm still just guessing, though. If you can find a pot replacement and it seems easy enough to change, you could try it and see.

From the part numbers i've been gathering inside the receiver they're still being produced to this day, even the ALPS potentiometers.
I could probably take this to a repair guy and see what he says, i'm very much an amateur when it comes to electronics.