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The Idiot's Guide to Using DeOxit (revisited)

brian222 said:
I'll admit it...I'm nervous around electricity. I've read every post on this thread and people are moving this moving that...once my amp is unplugged and the cover off I can just stick my hands in there and do some work??
Click to expand...

Well yes and no.

The large capacitors that are used in the main power supply can hold lethal charges for a long time.

So keep your fingers away from those.

But otherwise if you are careful you should be fine.
 
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Lots of good information in this thread. My take away from all of this is there is a time and a place for different types of cleaners and different types of lubricants and using the wrong product in the wrong place can make things worse.
 
Rob41 said:
Lots of good information in this thread. My take away from all of this is there is a time and a place for different types of cleaners and different types of lubricants and using the wrong product in the wrong place can make things worse.
Click to expand...

Exactly.
 
So, are there different deoxit cleaning "kits" for different receivers out there say? I've got a Pioneer SX 750 and have bought the deoxit red and the faderlubed. What else am I needing? Gold?
 
lebloom said:
So, are there different deoxit cleaning "kits" for different receivers out there say? I've got a Pioneer SX 750 and have bought the deoxit red and the faderlubed. What else am I needing? Gold?
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Lol. That's funny.


Sent from my galafreyan transdimensional communicator 100 years from now. G
 
Oh wait! You meant DEOXIT GOLD. I thought you were frustrated and you said gold because. Sigh. Ok.


Sent from my galafreyan transdimensional communicator 100 years from now. G
 
So wait. If I use DEOXIT gold on my RCA connectors it replaces the need to use silver conductive paste?


Sent from my galafreyan transdimensional communicator 100 years from now. G
 
To think I used to pay 200 for a deoxit job in nyc. Don't I feel silly. I got the nerve, and it wasn't too hard. Had to do two rounds on the new sta 2000.
 
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I have a 20 year old amp that was starting to get scratchy so I thought the pot cleaning would do the trick. It did go away but then came back a few months later. Thinking I just needed to do a better job I decided to clean the pots again. This time I really saturated the pots and worked them back and forth quite a bit. Now when I turn the amp on there is no sound. The power lights come on and I can hear the amp thump on a second after power is applied but there is no sound. If I turn the volume all the way up I can barley hear some ticks and clicks that go with the beat of the music being played.

Any idea what I did to it and if I can fix it my self?
Is it possible that when I turned it on with deoxit residue over several of the boards I shorted something out and need to bring it to a repair center?
 
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BrianAAA said:
I have a 20 year old amp that was starting to get scratchy so I thought the pot cleaning would do the trick. It did go away but then came back a few months later. Thinking I just needed to do a better job I decided to clean the pots again. This time I really saturated the pots and worked them back and forth quite a bit. Now when I turn the amp on there is no sound. The power lights come on and I can hear the amp thump on a second after power is applied but there is no sound. If I turn the volume all the way up I can barley hear some ticks and clicks that go with the beat of the music being played.

Any idea what I did to it and if I can fix it my self?
Is it possible that when I turned it on with deoxit residue over several of the boards I shorted something out and need to bring it to a repair center?
Click to expand...

Welcome to AK! and sorry to hear of your predicament. First, tell us what kind of amplifier or integrated amp it is, pics if you have them.

Second, look very closely in and around the pots and the boards and check for any excess or residual deoxit material. Although non-conductive, it isn't a good idea to power up gear if there's a lot of fluid around. So get out some non-lint wipes or q-tips, power the gear down, pull the plug, wait 30 minutes, then get in there and clean the area in question. If you have some compressed air, you might want to blow the pot out gently if you really soaked it. Remember, with Deoxit, less is better, it will distribute and all you need is a small amount and patience.

Now, it is known that some type of conductive plastic potentiometers can be damaged by deoxit. Best to try to dry the pot out with compressed air lightly, then let the unit sit overnight or at least 24 hours to dry out, then try to exercise the pot, and then power up and see if it works.

Some have suggested in this case, if it doesn't work after a couple of days, you may have to flush it out with something like MG chemicals contact cleaner, non-residue type I think. If that doesn't work, then you'll probably have to replace the pot with a new one, and that may require a tech trip.

Good luck!
 
Thanks for looking into my issue.

It is a Harmon Kardon PM655 integrated amp/preamp. I can take some pictures if it helps but there is no obvious defect. If it helps here is a link to a service manual for it.

http://elektrotanya.com/harman_kardon_pm655_sm.pdf/download.html

When I first cleaned it I was careful and only used short bursts to clean the pots. When it went bad again after only a few weeks I used the, if less is good too much is better, attitude and really soaked it. I held the straw to the pot and blasted it for 3-4 seconds until it was shooting out the other side. I also squirted cleaner in the back of the buttons. I didn't want to have to open it up in a few weeks again. Everything that could twist or move was saturated with cleaner. When I was done the table was covered with a layer of oil slime from the cleaner. I didn't think it would harm the other electronics. It smelled of cleaner for a few days. It has been about two weeks now and the smell has stopped. I am trying to narrow down what I may have done so I can figure out if it will be too expensive to repair, or if I can fix it myself. When I told the guy at the repair center about this he said it is always worth fixing good older equipment becuase the stuff made now is junk compared to twenty years ago. If it will cost over $150 I will need to think about that but he can't guess on a dollar amount until he gets into it.

The pm655 only has the standard rotary pots and a few push button switches.

Normally when it worked when all sources were off and the volume was turned at and over %50 there would be an audible hum. Now it is dead silent until you get right at %100. Then there is faint clicks and pops with the music being played. Is the amp protecting itself from really shorting out with some safety feature? I will try to blow some air through it to make sure it is thoroughly dry everywhere. Could a problem with the volume knob be doing this. Behind the volume knob was a blue box about 1"square. I unscrewed it and it looked like a big pot with the wiper now exposed. I saturated that area and screwed it back together. Maybe I need to open that box up so it can air dry.

I would really like to get this working as it has been an excellent piece of equipment for twenty years. If the bill will be over $150 I need to consider the fact that the capacitors won't last forever. I don't know how longs caps last in amplifiers but I would think 20-30 years would be about it. When those start to go I think that will be the end of it.
 
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5514.jpg


If the power lights come on, the power supply is probably still ok.

check the back of the amp's connections to your speakers and your sources to be sure they are ok.

Check the preamp out and power amp in sockets - was there ever a U shaped connection between the out and in? If yes, double check that they are clean and inserted all the way in. Also, sometimes the connections bridging the pre out/amp in internally can become corroded or even broken. If no, then try below.

Get a standard RCA stereo cable and, if you have a spare amp, wire the preamp out to the new amp in and see if you get sound out of the new amp to your speakers. This checks the preamp section.

Similarly, get a music source with a volume control (iPod, CD, Computer, or another preamp) and wire that to the HK amp in, and see if you get sound out of the HK. This will check the amplifier section.

This way, you can then isolate or narrow down the problem to either the preamp or amp section of the HK. Then your troubleshooting can continue.
 
BrianAAA said:
I have a 20 year old amp that was starting to get scratchy so I thought the pot cleaning would do the trick. It did go away but then came back a few months later. Thinking I just needed to do a better job I decided to clean the pots again. This time I really saturated the pots and worked them back and forth quite a bit. Now when I turn the amp on there is no sound. The power lights come on and I can hear the amp thump on a second after power is applied but there is no sound. If I turn the volume all the way up I can barley hear some ticks and clicks that go with the beat of the music being played.

Any idea what I did to it and if I can fix it my self?
Is it possible that when I turned it on with deoxit residue over several of the boards I shorted something out and need to bring it to a repair center?
Click to expand...

In theory contact cleaner is non conductive, at least the ones I use. You could try a zero residue plastic safe cleaner. Not one with a lube. Something like this http://www.mcmelectronics.com/product/20-2315 or LPS also makes a good one.

Set it up on the side with the weight on the bottom on newspaper and clean it up. Working all the controls. Let it dry completely.

Do yourself a big favor if thinking of working on others. Build a dim bulb tester for the future.


Barney
 
Thanks for the ideas. That is a picture of 655 back that I have. The split pre amp out and amp in is switched by a button on the front.

What I found so far is that if I plug an ipod into the amp in, select split amp, and use its volume control it works fine. The problem must be with the pre amp controls. In case the integrated/split amp button was broken I did try looping from the pre amp out to amp in jacks on the back and using the split amp setting. This did not work. So it appears that some part of the preamp functions has failed. Does this sound like a volume knob problem or could it be any of the pots/switches? Obviously my cleaning screwed up one of these knobs. On the positive side I won't have to worry about cleaning it again since the only way I can get to work is to bypass all of them.

In case I can't fix it is it possible to run straight from the CD out into the amp in with some type of outboard volume control in the middle? If anyone makes an external volume knob with line in and out that might be the way to go. Would replacing the volume knob fix the original problem? I kind of think this is where the problem is since moving the volume all the way does not produce any hiss.
 
BrianAAA said:
Thanks for the ideas. That is a picture of 655 back that I have. The split pre amp out and amp in is switched by a button on the front.

What I found so far is that if I plug an ipod into the amp in, select split amp, and use its volume control it works fine. The problem must be with the pre amp controls. In case the integrated/split amp button was broken I did try looping from the pre amp out to amp in jacks on the back and using the split amp setting. This did not work. So it appears that some part of the preamp functions has failed. Does this sound like a volume knob problem or could it be any of the pots/switches? Obviously my cleaning screwed up one of these knobs. On the positive side I won't have to worry about cleaning it again since the only way I can get to work is to bypass all of them.

In case I can't fix it is it possible to run straight from the CD out into the amp in with some type of outboard volume control in the middle? If anyone makes an external volume knob with line in and out that might be the way to go. Would replacing the volume knob fix the original problem? I kind of think this is where the problem is since moving the volume all the way does not produce any hiss.
Click to expand...

Double check the preamp into another amp before anything else to verify the problem is with the preamp. I'd recommend exercising all switches and double check correct settings so that signal SHOULD be coming out of the preamp.

Replacing the volume control (not knob) may be needed but best to troubleshoot the signal from input to line section to output to see where the problem is, it might not be the volume control itself, or not just it.

External volume controls (or passive volume controls) are available but not cheap. Also, they sometimes don't interact well with source and amp. Temporarily best to use another preamp if you have one, or a source with its own volume control built in, some CD players have that.
 
patience, take your time to think this through, troubleshoot, and then work on it. Rushing and trying trial and error fixes doesn't always lead one in the right direction or to the correct conclusion.
 
Well, I think it is safe to say I screwed something up in the preamp circuitry, but I have no idea what it is or if I can fix it. The pre out into another good amp has the same problem. I unscrewed the volume control pot and as expected it had oil in it. I have had it open and drying for two days now. The first day it got a bit better, I could faintly hear the music at %50 vol, but now for some reason it has gone back to nothing until %100. If there are any more steps I can do to narrow down the problem I would like to try them. I am obsessed with finding out what I did to learn from it and because of a bit of OCD.

I was thinking of putting an external volume control in line with the cd out to use the amp section when I realized I already have one. The headphone out on the CD player. I assume it is the same quality as the line out in the back but with a volume control. It is ghetto but it does work. As I said I would like to continue trouble shooting if there are any more ideas.
 
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