Yamaha T2 need an alignment?

Discussion in 'Tuners' started by belgianbrain, Feb 26, 2013.

  1. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    I just got a beautiful T2. It appears all original inside. Sounds fabulous.

    I'm going to perform an electrolytic recap and replace all the old caps with new Elna Silmic. I presume any capacitors that are crucial to tuning will not be electrolytic? (This is my first time working on tuners, so I'm learning)

    Does anyone think there would be much to gain from an alignment?

    The only reputable tech I can find to do it is 500KM from here. If anyone can suggest someone in the Greater Toronto area, I would appreciate that as well.

    If a realignment is likely to make a big difference, I will bear the cost and trouble of having it done. But, if the difference is likely to be minor, I'd rather not do it.

    Can anyone speak from experience?
     

     

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  2. rcs16

    rcs16 Super Member

    Messages:
    3,631
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    Baldwin, Ontario, Canada
    If the tuner is working fine I'd leave everything as it is. If you need my services, I probably can offer them but to be honest leave well enough alone.
    I live in the GTA area and I have a FM signal generator & other test equipment need for such a task. I have adjusted my Pioneer SX-950 before. I do not think changing ecaps should affect the tuner alignment. I have downloaded the SM, after reviewing it, now I certainly say leave it alone, you will be risking damaging something, especially if you have little experience with a tuner as complicated as this one and not knowing your mechanical/soldering skills. There are only a couple of ecaps in the signal path, you will not notice any differnce in this tuner by chnaging a couple of ecaps.
    Enjoy your tuner

    Rick
     
  3. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    Thanks for the offer, RCS.

    I'm comfortable with my soldering skills - I've rebuilt a few units and even built my own DAC and preamp. I replace electrolytics to future proof against failure - not so much to improve performance.

    I think I'll do the recap and then evaluate what to do next. If reception seems good, I may leave it as is.

    But, if there is anyone in the GTA who has lots of experience aligning tuners, I'd love to hear about him.

    BTW, which ecaps would you say are in the signal path?
     
    Last edited: Feb 26, 2013
  4. MX117.MC7150

    MX117.MC7150 Listener Subscriber

    Messages:
    5,252
    Location:
    Jersey Shore
    dr*audio in the Cleveland area. Punker in Flint, MI area, Terry DeWick in Knoxville, TN, Stereo Surgeons in Hartford, CT, Bob@FM in upstate NY (though he rarely, if ever, takes in outside work). Don't recall if there are any tantalums in the T-2, but they should go, as well.
     
  5. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    What does one replace tantalums with? New tantalums?

    A bit odd...the schematic has a symbol for tantalum caps, suggesting there are some, but there are none on the parts list.
     
    Last edited: Feb 27, 2013
  6. rcs16

    rcs16 Super Member

    Messages:
    3,631
    Location:
    Baldwin, Ontario, Canada
    For a tantalum replacement, I use MLC , use X7R or better.
    or low leakage/high ripple current ecaps
    Tantalums are still available but very expensive.
    Tantalums are fairly easy to distinguish from other types
    I found the SM on http://sportsbil.com/yamaha/
    Follow the signal path, it is highlighted, to see what ecaps are in there.
    Good luck fixing one of these if something goes wrong, good ole TTL logic for the freq display section as well.
    If you get over your head, or in trouble, I can probably fix one of these or tune it up if that is the case. Looks as if it was well designed/mfg. Send me a PM if this is the case.
    Rick
     

     

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  7. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
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    Greater Toronto Area, Canada
    Thanks for the advice, Rick. I'll update the thread as I progress. :)

    Ordered the Elna Silmic caps today. Got to find the cleaners for the tuning capacitor and then I'm off to the races.
     
  8. rcs16

    rcs16 Super Member

    Messages:
    3,631
    Location:
    Baldwin, Ontario, Canada
    This forum has a few threads on cleaning the var cap, they say to use compressed air, but at a very low force as not to damage the fins. It is delicate work as these fins are very fragile and can distort very easily.
    Take care
    Rick
     
  9. L'wood

    L'wood Active Member

    Messages:
    230
    Location:
    Chicago
    FWIW, I had a T-2 aligned a few years ago and the tech (who is very trustworthy and excellent) told me that was a waste of time, it was spot on.
    But I didn't have anything replaced.
     
  10. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    I appreciate the insight.

    I'm going to do all the work myself (recap it and clean the tuning capacitor) and I'll see how it behaves afterwards.

    If the tuning seems solid, I may leave it be - at least for now.
     
  11. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    Well, I did a full recap of this unit and cleaned the tuning capacitor as described in the tuner section of this web site. I also changed some bulbs.

    I now have a weird problem.

    When I first received the unit I hooked it up to my CA-2010 and it sounded fine to me. Did the full recap and RF front end cleaning, hooked it up, and it sounded fine.

    I then changed the two bulbs that illuminate the needle. Deoxit was then applied to variable output pot and the output RCA jacks on the rear and I closed it up.

    Hooked it up to my M2 and...volume on one speaker is much lower than the other! It does this for all settings, both sets of outputs, even the record calibration test tone does this. Mono mode does it too. Volume on right channel is two lights lower on the M2 power meter. Right channel does not sound distorted or anything - just lower volume!

    Did it do this when I bought it? I don't think so, but I can't say I paid really close attention. My speakers on my CA-2010 in the basement are very close together so it would've been harder to tell. Did it do this after my recap? I don't think so, but again, same issue - I tested it on my CA-2010.

    Any suggestion on where to focus for the hunt for the problem? I assume I can rule out the RF front end? I assume I can rule out what appears to be the digital display circuit in the shielding can under the amplifier board?

    I assume problem is likely post amp board? Could it be anywhere else? The only thing I did to that board was replace 3.3uF bipolar coupling caps with new Nichicon Muse bp caps.

    Suggestions would be greatly appreciated, as I don't have a lot of experience trouble shooting these sorts of things.
     
    Last edited: Mar 9, 2013

     

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  12. FauxHall

    FauxHall Super Member

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    1,537
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    I don't have any help on your channel imbalance issue but I can offer some insight on the alignment question.

    Three things affect the original manufacturer's cost of building your tuner - labor, materials, and design. They interact as a cheaply designed tuner can save labor; better materials and parts can save labor and so on.

    A big cost is the final alignment of the unit before shipping. It has to hooked up to a test rig and then someone with skills has to do final adjustments to bring it into specifications. The original design can affect that labor cost by keeping alignment simple or offering sloppy acceptance criteria.

    That's why some manufacturers offer essentially the same unit but use a different model number with slightly revised cosmetics and tighter specifications for a higher cost model.

    A vintage tuner will have changed with time since it left the factory so its performance will be different - usually sloppier - than when it left the factory.

    A real professional with good test instruments (an area of considerable improvement over the years) and realign your unit to optimize its performance. He can do a much better job - at a price - over what the factory originally offered. Sometimes not, but most units can be improved within its original design.

    An analogy is "blueprinting" a car engine to increase horsepower. For tuners, that might mean replacing the IF filters to better match them - a time-consuming and expensive process for the manufacturer and for the technician.

    Read Mr. Beezley at http://ham-radio.com/k6sti/ for some examples of what can be done.

    So even if your new-to-you tuner seems in pretty good alignment, a realignment by Dr. Audio or RadioX or several other specialists will usually be worth the investment - but not always - your as-found unit is on a bell curve and yours might be on the good tail.
     
  13. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    BAD 2SK68A in output buffer of post-amp board on Right channel.

    What can I replace this with? I have BF245A on hand....
     
  14. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
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    Found a few suitable replacements (guys in Yamaha thread helped) and they're on order. Almost done!
     
  15. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    1,971
    Location:
    France
    Yamaha t2 fet 2sk68a

    Hello Belgianbrain

    Wich 2SK68A do you need ? original type does exist !

    Yamaha part number IE100510 :
    (2SK68A, K1,K2)..............IDSS for K1......0,5 to 1
    for K2......0,75 to 1,5
    IE100520 (2SK68A/L1,L2)....IDSS for L1...1 to 2
    ......................................IDSS for L2...1,5 to 3
    IE100530 (2SK68A/M1,M2)....IDSS for M1...2 to 4
    ........................................IDSS for M2...3 to 6
    IE100540 (2SK68A/N1,N2)....IDSS for N1....4 to 8
    .......................................IDSS for N2....6 to 12
    IE100550 (2SK68A/L2,M1,M2,N1)....IDSS for L2 1,5 to 3
    ................................................IDSS for M1 2 to 4
    ................................................IDSS for M2 3 to 6
    ................................................IDSS for N1 4 to 8
    IE100560 (2SK68A/M,N).................IDSS for M 2 to 6
    .................................................IDSS for N 4 to 12

    be carefull when you change a 2SK68A for another one , specifications can be different !
    :scratch2:
     
  16. belgianbrain

    belgianbrain Super Member

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    1,201
    Location:
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    The schematic actually does not specify.
     

     

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  17. Nick_G

    Nick_G Active Member

    Messages:
    493
    Location:
    Whitchurch, Hampshire, UK
    Good luck with fixing this. I have the silver version of this tuner and for me it has produced the best sound of any tuner I've ever had in my system. The RF performance is also excellent. I had great fun logging lots of stations in Germany and France with it during a big tropospheric opening last November.

    I don't plan to have anyone touch it unless it starts playing up.

    Regards,
    Nick
     
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  18. avionic

    avionic " Black Knights " Subscriber

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    41,190
    Location:
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    FET ranking codes usually printed on the FET. Get a magnifying glass.
     
  19. belgianbrain

    belgianbrain Super Member

    Messages:
    1,201
    Location:
    Greater Toronto Area, Canada
    NTE 458s seemed like a perfect replacement to the 2SK68A, as far as my scope is concerned. Swapped out the bad part and both channels showed identical output with the test tone input. I then swapped the good one too, so both channels are using the same output buffer transistor.

    T2 was completely recapped with Elna Silmic and Nichicon Muse. Tuning capacitor was cleaned. Some lamps were replaced.

    Sound quality of this tuner is awesome. Tuning capability strikes me as fair. Of course, I'm in the burbs and I'm only using a dipole antenna in my living room, so maybe these are practical limitations. On the other hand, maybe an alignment would improve it. I'm considering dropping it off at RadioXTuners later in the spring.

    What's your experience with this tuner? Should it be able to easily pull in a station 40-60 miles away using a dipole and lock onto stereo with little interference, or are my expectations too high?
     
  20. Nick_G

    Nick_G Active Member

    Messages:
    493
    Location:
    Whitchurch, Hampshire, UK
    All I can say with mine is that it is slightly better than my Yamaha T-85 from an RF performance point of view, using a 5-element Yagi on the roof here. I have never tried them on a dipole or indoor aerial. Of course, as always YMMV.

    Did the recap make a big improvement to the sound?

    Regards,
    Nick
     

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