How to clean a tuner (analog)

Discussion in 'Tuners' started by dr*audio, Jan 17, 2008.

  1. richinnc

    richinnc New Member

    Messages:
    37
    Location:
    Garner, NC
    Pioneer SX-727 Tuner Issues

    I have a Pioneer SX-727 that I picked up recently that sounds and works great except for the tuner. On strong stations the signal strength will be about 3.5 on the meter, then it will jump to almost 5 and the stereo light will come on. It bounces like this continually, or often it will just hover around 3.5 and remain in mono. I did a basic alignment (don't have a distortion meter so am limited on my tuner alignment capability) and when the meter does jump up the sound is strong and clear.
    (Also note that AM does not tune in at all except when the FM signal is strong, then I can quickly switch to AM and some stations will tune in. This usually only lasts for 10-15 seconds though, then the AM signal is gone and switching back to FM the signal has dropped again). I found that rotating the tuner back and forth numerous times will usually cause the FM signal to come in strong for perhaps a minute or less, then it will bounce back and forth or settle back to 3.5. I sprayed the tuner fins with CRC QD contact cleaner, put faderlube on the points noted herein, and it seems to have helped a little, but overall the symptoms still remain. The voltage supply is 12.5 volts and clean so that does not appear to be an issue. Any suggestions would be most appreciated.
    I'd also like to thank the contributors to this thread as it is an absolute wealth of information!
     
  2. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    The tuner needs cleaning. Spraying the fins does nothing unless they are dusty, and if they are you need to used compressed air, not cleaner. You didn't clean the contact points before you put the Faderlube on them so that didn't work. Go back, re-read the instructions and follow them exactly.
     
  3. richinnc

    richinnc New Member

    Messages:
    37
    Location:
    Garner, NC
    Thanks dr*audio for your reply. Actually I should have stated more clearly what I had done. The first thing I do when I get a receiver is completely blow it out with compressed air, including the tuning capacitor if it's dirty, so that had already been done. I sprayed down the entire tuning capacitor with QD this morning as it still had a bit of dust as well as some light oxidization on some of the fins. I made sure to hit the contact areas as well. I then blew it out again with compressed air and applied the Faderlube as detailed in the instructions. As noted it did seem to help but did not cure the problem. I'm thinking I should remove the shield as maybe there's more oxidization that can't be seen on the FM front end board.
    I'm watching the receiver right now and the signal strength needle is bouncing, then will settle in for anywhere from a couple seconds to as long as a minute at full strength on the meter, then drop back to about 3.5. I'm going to let it just cook for a while and see if there's any change. If not I'll remove the shield and see what I find.
     
  4. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    You need to target all the ground contacts on the shaft and then work it back and forth across it's entire range 30 times. Sometimes you will still see residues on the contacts and you have to use Q-tips and alcohol on them to get the residue off.
     
  5. maddog37

    maddog37 Well-Known Member

    Messages:
    865
    Location:
    VT/NH Boundary
    I am pleased to say I followed dr*audio's instructions to the letter on three tuners yesterday and the difference with these simple instructions is wonderful. Not that there's a lot to listen to, but the couple of stations I do listen to are much clearer. Thanks dr*audio - lots of good advice.

    Tuners:

    Kenwood KT-7500
    Akai AT-2600
    Nikko NT-890
     
  6. WillStardust

    WillStardust Active Member

    Messages:
    125
    Location:
    Concord, NH
    bungling tuner cleaner seeks advice

    I am new to this so please go easy on me...

    I am trying to restore a Realistic STA-850 that I recently acquired (yes, I know it won't go down in audio history as anything great).

    The lamps that illuminate the tuner section were bad. They look like fuses. After a great deal of searching, I spoke to a nice fellow at OPTECH in Andover, Ma. He sent me the proper replacements and I installed them successfully, and she lit up just fine.

    I am sure the tuner was dirty, there was an annoying problem whereby the left channel fritzed in and out, and signal strength waxed and waned. No such problem when I used the unit with other input sources.

    I felt emboldened by my success with the lamps and I read Dr. Audio's tuner cleaning instructions. I vacuumed first, then used QD Electronic Cleaner on the fins (states leaves no residue on the can). I used a lot. I also worked the knob back and forth as advised.

    Now the tuner hardly works at all, barely picks up one station. Perhaps I cleaned off whatever lube was remaining on the contacts... Will the application of fader lube save me? Or did I cause a bigger problem? The fader lube is expensive and I am sure I would only need a tiny amount. Is there an alternative product? Or perhaps I'm in over my head... I am reluctant to spend the money for the fader lube if I really screwed things up.

    Any advice would be greatly appreciated.
     
  7. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    You sprayed the cleaner in the wrong place. Go back and re-read the instructions, and look at the picture. You need to spray it on the contacts that touch the shaft.
    It may be that the cleaner detuned the rf circuits but the effect should reverse itself after it dries. Also possible you used too much and got it on some sensitive components and damaged them, but not very likely. Usually this only happens with styrene caps and I don't think there would be any in a tuner.
     
  8. jrculler

    jrculler New Member

    Messages:
    1
    Location:
    Mobile, AL
    What are some good sources for the contact cleaner and faderlube?
     
  9. jim249

    jim249 AK Subscriber Subscriber

    Messages:
    391
    I would be careful putting too much non-residue contact cleaner in the tuner. You will wash out any of the lube put in there by the manufacturer. Your dial string will start to slip and won't work right. Been there and done that with a Marantz 2225 project.
    update: I loosened the tuner circuit board and tweeked it to tighten up the tuner string. Seems to work fine now.
     
    Last edited: Feb 14, 2015
  10. Brlux

    Brlux New Member

    Messages:
    2
    Wow great thread. I have an old JVC JR-S400 I bought from a teacher back in high school. I always loved how it sounded and looked. The other day I got some rough shape Cerwin Vega D-7s and reformed them. I pulled out my JVC and it had a lot of noise in the pots and switches, some Deoxit D5 spray fixed all those up nicely.

    The radio tuner was in very bad shape, it was hard to tune a station. On FM It was like it would start to come in, and as you tried to center on the station it would abruptly drop out and then pop back on. If you could get it to lock in it would drift after a little time. The centering needle was almost useless. I pulled and checked most the electrolytic caps, they were all fine. I re soldered most of the joints on the tuner and still no improvement. I was about to take it in to a repair shop fearing the bill for repair and re tune would be ridiculous.

    After finding this post I made sure to re blow out the variable cap with canned air and then used my spray can of Deoxit D5 to lube all the points at which the tuning shaft passed through the frame. There was actually little bent pieces of spring steel like metal soldered to the frame that would apply pressure to the side of the shaft as it passed through each cavity. I did not spray the D5 on the the variable cap! I sprayed it in to the garbage and then moved the spray straw over to where i wanted apply the Deoxit. There would be a small drop that would form at the bottom of the straw after spraying. It was a perfect amount for lubing each point and it did not mess anything up. After spinning the dial back and forth for a while I noticed some green tarnish like material mixed with the Deoxit that was flowing out of the areas where I had lubed. I tried the radio out and it was back to it's good old self, tuning as effortlessly as I remember from back in my high school days.

    Now I have a great old system set up in the front room that is a pleasure to listen to.

    Thanks
     
  11. fishfun83

    fishfun83 New Member

    Messages:
    3
    Dr Audio
    I have a Pioneer SX-1000TW and the stereo indicator light was coming on but not as frequently as I thought it should. Figured I needed to clean the contacts with a non-residue cleaner. I bought some CRC Electronic Cleaner which is Non-residue. I squirted a small amount at the contact points and went through the stations 30 times back and forth. I did not put any faderlube on because I just ordered it and it is coming in 2 days. Now...when I turn on the receiver without the faderlube, the stereo indicator light does not come on. I don't believe I put too much on the contact points. Does the tuner need the faderlube to fully work?
     
  12. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    No, but you need to wait for the cleaner to fully dry, you may have detuned the rf circuitry a bit. Usually, the stereo light not coming on is caused by the receiver needing alignment. This requires specialized expensive test equipment and is not something an amateur can do. The SX-1000 has a primitive MPX circuit and is more difficult to align than a newer receiver. Newer receivers only have one control to adjust and you can just tweak it until it receives stereo. Not so with the SX-1000. Take it to a reliable tech with rf experience.
     
  13. JamVal

    JamVal Super Member

    Messages:
    1,189
    I've been reading this read with interest since getting another issue solved on a Pioneer SX-838. The FM tuner works, but when tuning to an FM station the center tuning meter starts doing a jitter bug and the audio comes in and out with static. With patience and very slight touches to the tuning dial I could get most stations to come in.

    Following the instructions at the beginning of this thread, I but a very little CRC contact cleaner on the contact points between gang sections as shown in the nice photos on this thread. Then turned the dial back and forth several times.

    Now everything comes in smooth and clear, no more jitter bugging meter or static. Thanks much, Dr. Audi. Up until reading this thread I had been afraid to get anywhere near the tuning section.
     
  14. redavalanche

    redavalanche New Member

    Messages:
    7
    Hope I can get this answered here.
    Tuner- Lafayette LR-5555 A

    Cleaned tuner section and knobs/switches with CRC Non Residue Contact Cleaner. Everything was great.
    Then I used CRC 2-26 Lube on knobs/switches and without thinking/remembering I used that same lube and began spraying the whole tuner section. :(
    Realized I screwed up when I turned it on later.
    Have since cleaned tuner again and contact points with CRC Non Residue Contact Cleaner, worked the knob up/down.
    There was some white and green residue coming from contact points that I did my best to clean up. Waited a week to try it out.
    It is much better than it was when soaked with lube.

    The signal strength meter is very very weak now. Registers a 2 if lucky when it used to go to 5.
    Will cleaning again improve the signal strength? Did not want to assume anymore without asking.
    Hope someone can help me as this is a very nice unit I screwed up.
     
  15. JOLT65

    JOLT65 New Member

    Messages:
    3
    Location:
    Manila, Philippines
    Dear Dr. Audio,

    I am new to AK and recently acquired this Pioneer SX 1250 which is in great running condition. I need to get the innards cleaned when I get the guts to do it and work on the cabinet -since the tone was not as accurately done. It also has some tiny bruises but what irritates me is that the knobs are not as clean as I would like them to be. After cleaning, there still appears to be some sort of a stain or corrosion that would not come off. Would anyone know how to remove these or are they really perineally the case with the Pioneers? I have another Pioneer unit that has the same problem. Hope you can share some information on this or share some information where I can get better knobs. Thanks!

    PS. You will notice in the tilted photo, the tuner knob has some sort of a stain.. that's what I am talking about. Does not show much on the smaller ones but its also there in a smaller scale.

    I'm in the Philippines by the way...
     

    Attached Files:

  16. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    Windex will remove any stains on the knobs. If it won't come off with Windex, it's probably corrosion. You could probably polish that off with jeweller's rouge and a buffing wheel, or maybe chrome polish.
     
  17. JOLT65

    JOLT65 New Member

    Messages:
    3
    Location:
    Manila, Philippines
    Thanks Dr. Audio. I tried the compounds -while it appeared cleaner, the stains were still there. Tried using my dremel buffing wheel to no avail too. It appears that it is corroded.

    On another note, I went on to open up the monster to further clean it up with a tech friend of mine. The unit was relatively decent but I ambitioned to see if I can get the chassis rust dots cleaned off. It appears to be one hell of a job to do it. So I just brushed and cleaned off all the rust and dust I can remove and had the tech check on any loose components. Maybe when I figure out how to deal with the rust and find a good metal treatment for it, I'd venture to open it up again. For now, I took off the tuner section covers so I can find the proper treatment for them (that maybe I can apply also to the chassis for a complete restore).

    After cleaning, we put them back together again. Unfortunately, it appears that the lights on the tuner face pulsates to the beat! I just noticed when I was finally enjoying the unit! LOL! It was so subtle to notice earlier. Would you know where I did wrong? While it's amusing to have it softly pulsate together with the beat of the music, I don't think it normal for it to do that. Any idea where the problem is coming from?

    Sharing a few photos of the cleaning job... and consequently enjoying the new toy....
     

    Attached Files:

  18. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,172
    Location:
    Cleveland, Ohio
    You need a new power switch. Be sure to replace the cap across the switch also. It keeps it from arcing across the contacts, extending its life.
     
  19. JOLT65

    JOLT65 New Member

    Messages:
    3
    Location:
    Manila, Philippines
    Thanks Dr. Audio! Will do!
     
  20. RebelKat

    RebelKat Resident Tiger

    Thank you Warren! With your instruction, the seemingly dead tuner on the G-4700 had sprung to life, quietly pulling in lots of stations on a simple wire antenna. Amazing! DSCF0816.JPG
     

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