Deoxit making knobs too loose

Discussion in 'DIY' started by hanfrac, Apr 12, 2013.

  1. hanfrac

    hanfrac Banned

    I purchased Deoxit D5 and F5 to clean up some vintage receivers. Had good success on a Sony. Using it on an old Sansui, I ended up with some knobs having nice resistance and other knobs feeling too loose. I used D5 first, spraying it into the pots, then moving the control back and forth a lot of times. Then I sprayed F5 in to replace the lube and again, moved the control back and forth.

    The bass knob on the Sansui provides very little resistance and feels sort of cheap now. And it feels totally different from the treble knob. Fortunately, the Sansui (QR-1500) was free and I don't have big plans for it.

    I just purchased and received a Sansui 3300 receiver which I hope becomes my keeper and ends my search. I don't want to mess it up. But upon plugging it in for the first time last night, I heard a lot of popping and cracking. I suspect the source knob is the first place I have to go.

    Should I use a different product than D5 and F5 for this? I have read, but don't quite understand, that the 5% of something in D5 removes something important. And that there's a difference of opinion on whether F5 is necessary or not to replace lubrication.
  2. ConradH

    ConradH AK Subscriber Subscriber

    There are special damping greases used to give good feel to pots, camera lenses, microscope focusers and other things. IMO, a pot needs this stuff where the shaft goes through the bushing. Thick grease on the resistive element and wiper would lead to intermittents. There might be some thinner lube used there to reduce wear.

    Whatever was where, you cleaned it out with the D5. IMO, that's probably a good thing for the resistive element. If you could now force a bit of damping grease in where the shaft comes out of the bushing, that would restore the feel.

    Nye Motion Control (damping) greases

    Warning- you're getting your info from some joker on the Internet and his knowledge of this topic could be limited or completely wrong!
  3. Blue Shadow

    Blue Shadow Swapping Gear Subscriber

    A simple AK search using the google option for Nye grease will bring up a number of posts that indicate that the joker that answered your question is right on the money.

    The key bit of info is forcing the grease into the control.
  4. ConradH

    ConradH AK Subscriber Subscriber

    Here's something from the incomplete knowledge department- I just disassembled the input pots on a power amp. They were fairly conventional 1/4" shaft pots, but the style with a large hole in the back where you can see the rotating plastic part, similar to some large screwdriver adjust pots.

    Anyway, the shafts were free of any grease, but the damping grease was applied at the rear, where the metal shell presses the plastic part and wiper elements against the track. It was yellow and probably Nyogel 779 or something similar. It would be easy to regrease these, just work a little in the big hole at the back with a toothpick.

    Damping grease is more effective the larger diameter it acts on, so the rear pressure ring was a good place to put it.

    Unfortunately the two pots needed to match and over the years (or when built?) the nominally 25 kohm pots had drifted to 20 and 28 kohms, and the signal levels were quite different from channel to channel.
  5. roger2

    roger2 . Subscriber

    D5 contains 5% D100 and 95% something else, which includes solvents. Based on what has been said in other posts here, I believe it is the solvents in the 95% that dissolves grease. The DeoxIT product D100L has no solvents.

    When reading through threads here, the method that you describe in your original post is what is most often recommended for Deoxit use. But if one digs deeper it is possible to find that some users have reported issues. Two problems that have been reported are loss of smooth/silky feel in pots and that the carbon traces used in some pots can be damaged.

    Have a look at post #5 (including quoted portions) and post #9 in this thread:
    looking for instructions on cleaning pots w/ Deoxit

    Renew Volume knob "feel"

    Deoxit -- ruined my volume pot?

    One of my threads. See post #4 where there is a link to a Caig tech Q/A page with specific recommendations on product usage. Is this an atypical volume pot? Is it safe to clean with Deoxit?

    Personally, I have become more cautious about using anything in pots. I will only do so if I suspect a problem. I have purchased some of the D100L with a needle type applicator. I will try to apply it sparingly and, if possible, limit application to the wiper/track areas. YMMV

    Good luck
  6. hanfrac

    hanfrac Banned

    After reading all of this, I'm scared that I D5'ed my pots to death and perhaps turned this receiver into scrap. I did multiple shots of D5 followed by F5, trying to get rid of bad sounds, but made them worse.

    At last check, the receiver sounded mediocre and would only really work with headphones. If I connected speakers to the rear, even if the speakers were set to off, the sound would break up on the headphones and the speakers if they speakers were on. Remove the speaker connections and it would go back to sound ok (not great) through headphones.

    I took it to a local repair place, but I'm a little worried. He is against Deoxit, but in favor of WD40, which many people here seem to say is bad. It would be a shame to have to part the 3300 out because I ruined it after reading, but obviously not understanding, all of the deoxiting advice here.

  7. ConradH

    ConradH AK Subscriber Subscriber

    I question if one can do permanent damage to most pots, and that receiver sounds like it has something else wrong with it, not the pots. In any case I can't imagine it having to be parted out. It was made by man and it can be fixed by man (yes, that includes women).
  8. roger2

    roger2 . Subscriber

    First of all, I am not an expert on DeoxIt and did not mean to come off as an authority. I was trying to bring relevant discussion to your attention. My thought was that you may want to investigate prior to further Deoxit use, especially since you already had one not-so-positive experience.

    I am confused as to which unit is under discussion. In your OP you mentioned a Sony that you Deoxit'ed with no issues. Then a QR-5100 that, after a Deoxit treatment, had a different feel in the tone pots. And finally, a 3300 about which you commented "I hope becomes my keeper and ends my search. I don't want to mess it up".

    In your last post are you referring to the QR-5100 or the 3300?

    Is it possible that you have a lot of overspray inside the unit?

    Listen to ConradH. Probably not time to panic as there is likely to be some other explanation. The negative Deoxit reports that I pointed you to are rare occurrences. Please clarify the problem, the unit under discussion, and the sequence of events, i.e. was there a problem before, what was done, what was the result, etc. I will probably not be able to solve the mystery, but others here are able...
    Last edited: Apr 17, 2013
  9. hanfrac

    hanfrac Banned

    My name is Frank and I have a problem....

    Sorry. I have acquired 3 receivers in the past couple of weeks, all of which I have used Deoxit on.

    1 - Sansui QR-1500 where I lost some feel on the tone control knobs - they lost that nice resistance
    2 - Sony STR-5800SD, where I was successful in eliminating a little bit of static without loss of feel
    3 - Sansui 3300, which arrived with some problems which got worse after repeated applications of Deoxit

    When I started this thread, I hadn't touched the 3300 yet, but I had had the experience of loss of feel with the QR-1500. I tried to be careful with the 3300 in terms of very short sprays.

    I'm definitely putting the Deoxit aside. I'm waiting to hear from the tech on the 3300.

    And to prove I have a problem, I bought an STR-6055 on eBay yesterday (really cheap), so that will arrive next week. I have promised myself that this is my last purchase and once I see where I'm at, I will get rid of a couple of receivers. I'm really hoping the 3300 is the keeper.
    Last edited: Apr 17, 2013
  10. westend

    westend Audiopile Subscriber

    Hey, no real problems, you just have some "growing pains". When your collection of receivers gets so big that you run out of shelf space, you can then start selling. It's cool to hear all of the different brands and models of the best days of stereo.

    Yes, Deoxit can injure a carbon trace pot but it is rare if the chemical is used in usual manner. It won't harm a control that is metal, as is your Sansui. I would guess that the introduction of D5 and F5 loosened some grit and gunk inside the control and it may be causing some intermittent problems. It does sound like you may have another issue, though.

    I would be very wary of any technician using WD40 in any profession as his "go-to" cleaning and lubricating product. WD-40 is known to not get along with certain plastics and rubber. You can form your own opinions as to coconut oil being a good or bad lubricant.

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