Cleaning input selector on Denon PMA-980R

GreatGazoo

GreatGazoo

Member
Hi

I just picked up this amplifier for ~45 USD. The plan was to give it to my dad for christmas, as his old Pioneer has seen better days. The unit seems to be in good condition (can't test it as my own setup consists of active monitors and my sources are digital) and due to the sellers history I trust that it works as I was told.
Only problem I noticed is the input selector (which seems to be a frequent issue with this series), as it has a tendency to jump between the imputs randomly for a second when the knob is turned. It only happens sporadically and for now the problem seems to have disappeared, after I turned the knob for a minute or two, to loosen the dirt I assume is causing the issue.

The problem is that the pots are harder to reach from the inside than I expected, any chance I could try to clean it from the front instead? Will I be able to pull off the knob(s), by pulling it away from the faceplate, on this model? I'd rather not dismantle the entire thing unless I know it is the only option. For it's age it seems pretty neat and clean in general.

Any help is appreciated. Thanks and happy holidays.
 
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Also the volume knob could probably benefit from a tightening, as it is a bit wiggly... Again I assume that I can fix this by pulling the knob off and tightening a screw, but my hifi knowledge is pretty limited, as I use studio equipment in my home audio. Not exactly confident that this kind of pullable knob-design is as standard as I think it is (also the volume knob is motorized, not sure if this complicates the matter further).
 
I am afraid you need to remove the front panel first before getting a good access to the pots for proper cleaning with DeotIT fader lube. I don't have that model so I don't know for sure but there some knobs may have the set screws to attach to the shaft on the pot. You need to trun around the pot completely and look for the hole where the screw is hidden. Sometimes (in the very rare cases), you need to flip the unit and look for the holes on the bottom side of the unit. Do it slow and observe it carefully before applying force to remove the knob.
 
My PMA-860 does that occasionally. I took the top cover off and noticed that I'd have to take the front off to get at the pots and switches. I put the top back on and said I'd do it later. That was several months ago...
 
Thanks a lot to both of you for replying.

Honestly I feel there is a significant risk that I'll end up messing something up trying to access the pots the proper way. Especially now, where the problem has seemingly disappeared, I think Im gonna take the same route as Dave1701 and put the top back on and hope for the best :) All of the functions that are needed can be performed by the remote (which I got), so I'll just instruct my dad to use that for daily use.

Dave1701 how often is occasionally in this case? And do you have any "quick and dirty" tips, other can exercising the knob?
 
With the unit powered down completely, you can exercise the knob by turning it slowly from completely from left to right and vice versa for several times (like 10 or more). Turn the unit on and see if helps. If not, try exercising the knobs again. You might need to repeat several times. There is no guarantee the problem can be completely corrected but it's worth a shot since there is nothing to remove. Chances are 50/50 and hopefully, the chances are in your favor.

But like Dave and you are opting for it, leaving it for another day or to someone who knows what they are doing is a really smart move.
 
This thread has instructions for fixing OP's problem: http://www.audiokarma.org/forums/in...ems-with-input-selector-heres-the-fix.218030/

I don't mean to derail the thread, but while mine has not clicked in quite a while, it does cause distortion in the audio output that I can fix by jiggling the knob a bit. Is dirt likely the problem here? If it is simply a matter of shooting it with Deoxit, then I can unscrew the ZILLION screws in this thing to pull the faceplate and get to it. Other than that, I can't do much, as I can't solder. Ideas?

Get a new amp, maybe... apparently these selectors are a real pain.
 
Yup, thats what I did megasat16, but thanks again for replying.

Dereail away Dave1701 :) The amp is now out of my reach, standing in my parents' living room. Ive instructed them to only change the input via the remote and so far this has worked great.

I saw that thread too, but I don't have the skills necessary to perform the repair either (also the pictures have seemingly expired, which makes the instructions even harder to follow for someone like me, even if I could solder).

I have no tips for you Im afraid. Mine only acted up shortly when the knob was turned, not randomly. But a good cleaning with Deoxit is worth a shot in my opinion, can't hurt. I was personally very satisfied with the sound I got from this unit and I hope you mange to fix yours. If you want to look for a new amp Ive seen a few reasonable priced PMA amplifiers that utilized buttons instead of knobs (except for volume).
 
Welp, that was easier than I expected. On my PMA-860, there is no need to remove the front cover. The input selector knob is connected to a switch near the back of the unit. Pulled it apart and shot it full of Deoxit. Now it functions like new. Oh Deoxit! Is there anything it can't do?

GreatGazoo said:
Yup, thats what I did megasat16, but thanks again for replying.

Dereail away Dave1701 :) The amp is now out of my reach, standing in my parents' living room. Ive instructed them to only change the input via the remote and so far this has worked great.

I saw that thread too, but I don't have the skills necessary to perform the repair either (also the pictures have seemingly expired, which makes the instructions even harder to follow for someone like me, even if I could solder).

I have no tips for you Im afraid. Mine only acted up shortly when the knob was turned, not randomly. But a good cleaning with Deoxit is worth a shot in my opinion, can't hurt. I was personally very satisfied with the sound I got from this unit and I hope you mange to fix yours. If you want to look for a new amp Ive seen a few reasonable priced PMA amplifiers that utilized buttons instead of knobs (except for volume).
Click to expand...

I hope your parents like it. Opening mine up, I really liked the look of the innards; it seems to be a quality unit. Looking at google images, the 980R is quite similar inside. If it ever becomes a problem, it may be an easy fix like mine.
 
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