Aux911DG Problem

[Vincent D]

Hi John,
I mean, if I connect a CDP to the Optical Digital input, and then I select "Digital 4" which is the Optical Digital input, and then select "Digital Direct" the indicator on the volume control will light up,( as it should) but sometimes it Doesn't. ( If I selected it, and then selected another Analogue source 10 times in a row, it would only light up about 4 times out of 10) That's why I suspected a bad contact on the "Digital Direct" selector.

"Try this , with a tuner connected to all except the phono have source direct and exercise all inputs , then exercise source direct on and off." I've already tried that, and with analogue sources if the selector is set to "Digital Direct" I get sound to both channels, but its a very Bright sound and not normal. Again with analogue sources if I turn "Digital Direct" off, I only get sound from the right channel.
When I loosen the tension screws on the gears should I see a gap between the bottom of the gears and the pcb? because when I loosened the screws before it made no difference, and the gears were still sitting tight to the pcb. Do I maybe need to loosen the screws and then gently prise the gears away from the pcb so I can clean underneath it?

 

[skippy124]

Be careful that you don't let the worm gear lose contact with the gears on the two wheels that the worm gear drives otherwise you may lose rotational alignment between the two wheels.

 

[JOMARK911]

Skippy is right. Again you should not get any sound out of digital direct with an analog source connected. Your amp has got some issues that you probably cannot troubleshoot.
Skippy the only alignment we don't want to loose is the one between the two large gears , not the worm gear. He can mark a line on the two gears with a certain input selected so he can pull them out and clean the pcb underneath .

 

[JOMARK911]

Vincent if you do this make sure you mark a line that crosses both gears at the same point , straight one , and mark each gear either on the outer perimeter or the inner , and make sure that you don't mix the gears up. Write 1 and 2 on each one after you mark the line , and have cd selected.

 

[Vincent D]

Thanks John and Skippy,
I understand exactly what you both said, so I'll give that a go and report back.

 

[JOMARK911]

Oh and be very cautious . Gentle small movements. You don't want to ruin input selector.

 

[Vincent D]

Oh and be very cautious . Gentle small movements. You don't want to ruin input selector.

Ok..........
I've just spent about five hours on this. I cleaned the pcb under the gear wheels and got Deoxit Gold on there. Took a lot of trial and error to get the tension re-adjusted, but I finally got it right. Now the indicator light for "Digital Direct" lights up every single time I select it, and once again the CDP on Digital 4 (Optical) with "Digital Direct" selected, sounds excellent.
However, this time the other sources play, but as you know there are three options on the "Digital Direct" selector switch: "Off", "Source" and "Digital Direct". If I play an Analogue source and select "Digital Direct" there's just silence. (are there should be) Then, If I select "Off" I only get sound from the right channel, and If I select "Source" I get sound from both channels, but at a very reduced volume level. The Tone and Balance controls still don't respond with any configuration selected.
The "Loudness" button doesn't work, and I'm starting to think that the one channel problem might be something to do with the balance control, and If the tone and balance controls share a board, then maybe there's a problem on that board.
Anyway, I'm feeling a bit demoralized, and thinking there's not a lot more I can do at this stage. John,Skippy and Raj, thanks for all the time and encouragement you've put into this, I feel like I'm letting you down by not being able to complete it.

 

[JOMARK911]

It's ok Vincent, now you have to move to the preamp board in the front , and deoxit the source direct switch , and generally all the switches there. No big deal.

 

[Vincent D]

It's ok Vincent, now you have to move to the preamp board in the front , and deoxit the source direct switch , and generally all the switches there. No big deal.

OK John,
I'll try that now.

 

[Vincent D]

OK John,
I'll try that now.

I opened up the front and got some Deoxit on all the selectors. Of course the "Digital Direct" was the most difficult to access, its a long square tube that's buried in a mass of wires. I unscrewed it with its pcb, and pulled it out as far as I could. Because it's a radial switch, I was expecting to see a potentiometer, but it seems to be mostly plastic, and I couldn't see a wiper assembly, so I put some Deoxit into a medical syringe with a long needle and squeezed it into any openings and then continuously operated it for about ten minutes. I re-assembled the front and put some music through it.
Now, when I play an Analogue source, and select "Source" on the "Digital Direct" Selector, I'm getting full volume to both channels, and it sounds really good. If I select "Off" I still get only one channel working, but I can live with that. Unfortunately the "Bass", "Treble", "Balance" and "Loudness" controls still don't work, but luckily the balance seems to be centered, so its not really a problem, and if I need tone controls I could always run it through an equalizer. Any thoughts before I close it up?

 

[mjs1]

A quick question for you Vincent (or John) if you have the time. My volume pot is noisy. Does it have an opening for spraying Deoxit?

 

[JOMARK911]

A quick question for you Vincent (or John) if you have the time. My volume pot is noisy. Does it have an opening for spraying Deoxit?

I believe it does , but it's a fairly complicated 6 gang pot. Yes you could do it I suppose.

 

[JOMARK911]

I opened up the front and got some Deoxit on all the selectors. Of course the "Digital Direct" was the most difficult to access, its a long square tube that's buried in a mass of wires. I unscrewed it with its pcb, and pulled it out as far as I could. Because it's a radial switch, I was expecting to see a potentiometer, but it seems to be mostly plastic, and I couldn't see a wiper assembly, so I put some Deoxit into a medical syringe with a long needle and squeezed it into any openings and then continuously operated it for about ten minutes. I re-assembled the front and put some music through it.
Now, when I play an Analogue source, and select "Source" on the "Digital Direct" Selector, I'm getting full volume to both channels, and it sounds really good. If I select "Off" I still get only one channel working, but I can live with that. Unfortunately the "Bass", "Treble", "Balance" and "Loudness" controls still don't work, but luckily the balance seems to be centered, so its not really a problem, and if I need tone controls I could always run it through an equalizer. Any thoughts before I close it up?

Vincent while you are there deoxit every switch at least twice. Source direct is giving you hard time but there is the problem . If you insist you'll get it done and will have the off position available along with the tone controls and loudness. Just insist . It will clear eventually.

 

[Vincent D]

No worries John, I'll keep at it.

 

[mjs1]

Thanks John. I'll give it a try.

Marc

 

[Vincent D]

Thanks John. I'll give it a try.

Marc

Hi Mark,
You will need major disassembly to get to it. I have to open mine again tomorrow, so I'll post a few pictures.

 

[mjs1]

Thanks Vincent.

Marc

 

[rasenthiran]

Vincent,

I am actually facing the same issue with you. If its the selector switch is the culprit,i may clean it my self if possible. Sometimes i do miss the usage of loudness and tone control because i will have a drop out in one of the channel when it is selected using off position. The amplifier works good using source direct and digital direct.

 

[JOMARK911]

Yes this switch does this sometimes . It needs cleaning with deoxit or a similar pot cleaner . But it will have to be applied several times , work the switch , let it dry and then again.

 

[Vincent D]

Yes this switch does this sometimes . It needs cleaning with deoxit or a similar pot cleaner . But it will have to be applied several times , work the switch , let it dry and then again.

Here's a few pictures for Marc:







Remove top cover.








Remove all knobs and selectors. You'll need an Allen key for the selectors.







Remove the faceplate. A lot of screws.






Disconnect the two push connectors at the top left hand side of the selector

board, this will release the faceplate, and you can put it someplace safe.






g



That's the volume pot from the front, as you can see there's no access, so

remove the screws on the top, bottom and both sides to release the front.




It's not possible to pull the front away from the Amp as there's a lot of wires

Attaching it to the Amp, but you can open it just enough to get access to the

volume assembly. There's a slot on top of it where you can see the cogs of

the motorized volume control.




I used a syringe to inject Deoxit into this opening, then I lifted the

Amp and turned it upside down and side to side to flood the mechanism inside

with Deoxit.

Then I reattached the Volume control and operated it back and forth for ten

minutes, then I went through the procedure again with Deoxit lube. my volume

is 100% silent now. You could do some further disassembly and maybe then

you could actually see the pot, but personally I didn't see any need for this.