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Sony 262-SL Tape Recorder Exchange-Track Sound Very Weak

Discussion in 'Tape' started by Novice2017, Jul 25, 2017.

  1. Novice2017

    Novice2017 New Member

    Messages:
    23
    This venerable (but mono) tape recorder, still very clean, was used to record music many years ago (on 1/4" reel-to-reel tapes). The recordings were on both the "Normal" and the "Exchange" tracks in each direction of the tape. For years, the playback sound level of the two tracks was comparable in loudness -- with the volume knob left at the same position for playback on either track.

    Recently, and after not using the tape recorder for several years, playback of those tapes occurs at much lower (and much more noisy) level on the Exchange track than on the normal track. This is true no matter what tape I use among the old tapes recorded on this machine. And remains so regardless of whether I use the built-in speaker of the tape recorder or send the signal through a receiver by using the tape recorder's P.B. Monitor or the Line-Out outputs.

    I used Deoxit on the contacts of the Record/Playback switch on a little board inside the unit, and on some other contacts, but that did not help the above problem, although it got rid of the small amount of static noise that was present when I was changing the volume level.

    Also, I tried recording something new on a tape and play it back. The Normal track records and plays back very nicely (both through the built-in speaker and through a receiver), but the Exchange track is both very faint and very noisy. Both the old recordings and the new one were done on each track with the unit's "Magic Eye Recording Indicator" at the recommended level, i.e., with the two lights of the indicator "fan" almost touching, but not overlapping, except for momentary peaks in the signal.

    PLEASE, help! Any idea/suggestion will be greatly appreciated. It's the only machine I have to play back those old friends/tapes, and I do not want to lose half of the recorded tracks.

    Is my following (beginner's) thinking correct?

    1. It is unlikely that the Exchange REC/Playback head went out of alignment while the Normal head remained OK, since both are rigid with respect to each other. And if this is true, playing with the azimuth adjustment will not help, because it moves both the Normal and the Exchange heads together, right?

    2. It leaves me with the (only?) possibility that the Exchange head is worn out, but the Normal head is OK.

    3. If new REC/Playback heads are needed (part # PP 15-2902), will desoldering and soldering be needed to replace the heads and, if so, should it be done at the four wires right at the back of the heads or at the circuit board inside the unit -- I have not yet looked where those four wires go under the top cover. And would my 30W soldering iron be sufficient for this job?

    4. If new REC/Playback heads are installed, is it necessary to also replace the erase heads -- other than the, I assume, obvious reason that new heads will function better than old ones? I do not plan to do any new (mono) recording on this machine. I just want to be able to listen to the old tapes.

    Thanks in advance for any help.
     

     

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  2. oldvinyldude

    oldvinyldude AK Subscriber Subscriber

    Messages:
    1,644
    Location:
    Buckeystown Maryland
    It's very unlikely that your heads are at issue.

    First up, and easy to do-thoroughly clean the heads. Use isopropyl alcohol, at the purest you can find, and rub firmly on the heads-in the direction of tape travel. Use a clean cloth or cotton swab, avoid paper towels.

    If no go, then work the record/playback switch back and forth/in and out a whole lot of times-like 25-50. (not sure how the switch might be labeled-the idea is to exercise the contacts of the switch that is in the signal path from the heads to the record/playback circuit.) Do this with the deck off.

    Next, try a contact cleaner on that switch, and hit the record/playback level potentiometers as well. The favorite is Deoxit 5, but others may work pretty well.

    Lastly, the record\playback electronics may be at issue. Typically, leaking or shorting capacitors are mostly to blame. This work is beyond me, and may be beyond you as well.

    Hope this helps.
     
  3. Novice2017

    Novice2017 New Member

    Messages:
    23
    OldVinylDude: Thank you for the speedy reply! Please, know that I had already done everything you have suggested. I had used denatured alcohol to clean the heads (I had also demagnetized them), and I had sprayed Deoxit on the REC/Playback contacts (and all other contacts) and exercised them innumerable times. Indeed, I would not know where to start to diagnose a possibly leaky capacitor. If that is the case, the culprit would have to be in a circuit that affects playback and recording only on the exchange track, but not the normal track. From my very limited knowledge, it seems unlikely that the unit would have a totally different circuit for each track. My guess would be that a simple switch makes the change from one track to the other. So, I had given that switch (on the left side of the tape recorder) the Deoxit treatment as well. That is why I concluded, with much uncertainty of course, that the Exchange-track head is likely the problem. I hope that somebody else more knowledgeable than me comes up with a different idea or confirms my conclusion.
     
  4. Novice2017

    Novice2017 New Member

    Messages:
    23
    TESTING THE HEADS WITH A SCREWDRIVER

    I have an additional piece of information, which will hopefully help one of the experts on this forum to diagnose the problem. I read somewhere about a test, but the write-up was not clear on how to interpret the test. Here is the test and the results:

    1. While playing the Normal track of a music tape (for which the sound is very nice), I touched the tip of a small screwdriver on each of the four connectors at the back of the REC/Playback head. No change in sound was audible when two connectors (on the same side of the head) were touched by the screwdriver. (So, these should be the ground connectors for the Normal and Exchange heads, right?) Also, the bottom connector on the other side of the head did not produce any audible change in sound. However, touching the top connector produced some continuous humming noise in the sound.

    2. While playing the Exchange track of the tape (for which the sound was very low and very noisy), I did the same screwdriver test. Touching the two ground connectors had no effect on the sound, and neither had the top connector on the other side of the head. However, when the tip of the screwdriver got close to the bottom connector of the head (3/8" - 1/4"), but had not yet touched the connector, I got quite a loud continuous noise through the speaker.

    QUESTION: Does this mean that the Exchange head is worn out, or that the problem lies in another part of the electronics of the unit?? Or, does it imply something else beyond by ability/knowledge to imagine what it may be?

    Thanks in advance for any informed response.
     
  5. bdpop

    bdpop New Member

    Messages:
    1
    I have a similar issue. My Sony 262-SL has very low volume. What could be causing this. I have the service manual, but it is of very little help.
     

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