New B2 for complete rebuild.

Discussion in 'Yamaha' started by belgianbrain, Oct 6, 2017.

  1. Vint Age

    Vint Age B-1 With Yamaha

    Messages:
    2,159
    Agreed, why not remove the glue if you can. But with that said, having restored 7 of these so far, I've never seen any evidence of corrosion to component leads like you see with the glue Sony used in some of their gear ...
     
    Last edited: Oct 21, 2017
  2. belgianbrain

    belgianbrain AK Subscriber Subscriber

    Messages:
    1,200
    Location:
    Greater Toronto Area, Canada
    The inductor type I'm looking for looks something like this.

    inductor.jpg
     
  3. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately... Subscriber

    Messages:
    604
    Location:
    Amsterdam Area, The Netherlands
    No funky chemicals involved, just a small wooden scraper.
     
  4. belgianbrain

    belgianbrain AK Subscriber Subscriber

    Messages:
    1,200
    Location:
    Greater Toronto Area, Canada
  5. clinic-audio

    clinic-audio all on YAMAHA untill 1990

    Messages:
    1,749
    Location:
    France
    On my other B2, I tried shorting this output filter to assess the effect on sonics. I noticed a noticeable improvement right away, especially in the high range.

    Do you think that YAMAHA people did use a non necessary "filter" ?
    I think that "improvement" is not the right word . Difference , of course , the sound can't be the same without Bessel filter .
     
    Nashou66 likes this.
  6. Nashou66

    Nashou66 AK Subscriber Subscriber

    Messages:
    962
    Location:
    West Seneca NY
    Thats an Air core inductor but I would just leave it alone.

    Unless you have a LCR meter and want to wind your own.

    Nashou
     
  7. Vint Age

    Vint Age B-1 With Yamaha

    Messages:
    2,159
    Agreed
    and agreed, easy enough to wind a few turns of the right wire type on a pen as a form ... but what's there works quite well so why mess with it ... :thumbsup:
     
    Last edited: Oct 22, 2017
    Nashou66 likes this.
  8. avionic

    avionic " Black Knights " Subscriber

    Messages:
    36,824
    Location:
    Fort Dodge, Iowa
    Why ? Are they physically damaged ? That inductor should last forever and never change in value.
     
    Saint Johnny, Mr. Yamaha and Nashou66 like this.
  9. belgianbrain

    belgianbrain AK Subscriber Subscriber

    Messages:
    1,200
    Location:
    Greater Toronto Area, Canada
    My beef with the current inductor is that I can hear it, and the effect isn't positive (to my ears). But this is nothing new, I've had beefs with many resistors, capacitors, or inductors in the signal paths of various components in the past. I am very anal about my signal path. One great thing about the B2 is that there is very little in the signal path once you do the RCA input direct to driver board modification.

    I suspect the "problem" with the inductors is that they seem to be made of very thin gauge wire. New power amps I've opened up don't use this sort of inductor, they use large gauge wire like the inductor in the photo above.

    I think I'll roll my own with at least 18AWG transformer wire. It's a good excuse to get a good LCR meter. ;)
     
  10. Nashou66

    Nashou66 AK Subscriber Subscriber

    Messages:
    962
    Location:
    West Seneca NY
    Having a meter is nice , but this is what you need

    http://www.circuits.dk/calculator_single_layer_aircore.htm

    They have a multi layer calculator I used to wind my own Focus coils in the Marquee 9500LC CRT Projectors I have .
    Talk about modifying electronic gear, work on those beasts!!! Best thing tho with CRT projectors is the boards are all modular and pull
    out . Easy to work on in that respect, but video path is much more objective than with audio, you can see the difference different mods make much more so than the subjective side of audio mods. But in Video inductors do make a difference and the video amps are not much different then audio amps.

    Athanasios
     
    zaibatsu and rottalpha like this.
  11. rottalpha

    rottalpha Yamaholic

    Messages:
    1,176
    Location:
    Middle of Crook County
    very handy calculator. Thanks for posting the link!
     
    Nashou66 likes this.
  12. belgianbrain

    belgianbrain AK Subscriber Subscriber

    Messages:
    1,200
    Location:
    Greater Toronto Area, Canada
    Yes, thanks! I've tried a few online, but this is one of the better ones.
     
  13. belgianbrain

    belgianbrain AK Subscriber Subscriber

    Messages:
    1,200
    Location:
    Greater Toronto Area, Canada
    First two power supply boards are done. Replaced the following:

    1. All polar electrolytics replaced with, in order of preference: Panasonic FR, FC, or Nichicon PW, depending on availability;
    2. C227 and C228 replaced with Nichicon Muse BP and C225 and C226 replaced with Panasonic polypropylene;
    3. Big 18,000uF caps replaced with 22,000 uF Mundorf Mlytic AG and 1uF polypropylene bypass added;
    4. All green mylar caps replaced with new Panasonic polypropylene;
    5. New relays;
    6. All heavy power conducting resistors replaced with Dale CPF 2W or 3W and raised from board;
    7. Potentiometers replaced with Bournes multi-turn units;
    8. New heat sink grease for transistor heat sinks and heat sinks re-glued to PCB with epoxy;
    9. L201 and L202 replaced with custom home-made inductors using 16AWG solid copper transformer wire;
    10. Zener diodes D205, 206, D210 replaced;
    11. General cleaning, although I was not anal about removing old glue because it was VERY difficult to get off.

    IMG_20171107_194636.jpg IMG_20171107_194616.jpg IMG_20171107_194601.jpg IMG_20171105_152959.jpg IMG_20171105_152932.jpg IMG_20171105_151755.jpg
    IMG_20171105_151807.jpg
     
    Last edited: Nov 7, 2017
  14. rottalpha

    rottalpha Yamaholic

    Messages:
    1,176
    Location:
    Middle of Crook County
    nice coils

    I have a couple of observations:
    How are you going to support two of those caps? The ones sitting furter from the edge of that board
    and
    how are you planning on adjusting those multi-turn pots?
     
    Mr. Yamaha likes this.
  15. avionic

    avionic " Black Knights " Subscriber

    Messages:
    36,824
    Location:
    Fort Dodge, Iowa
  16. avionic

    avionic " Black Knights " Subscriber

    Messages:
    36,824
    Location:
    Fort Dodge, Iowa
    It comes off very easy with and straight exacto blade. And will look a hell of a lot better.
     
    Mr. Yamaha likes this.
  17. avionic

    avionic " Black Knights " Subscriber

    Messages:
    36,824
    Location:
    Fort Dodge, Iowa
    Hope you don't ever have to remove it. I would not have used epoxy.
     
  18. zaibatsu

    zaibatsu Active Member

    Messages:
    441
    A good way to soften glue is to soak a bit of cotton wool in acetone and leave it sitting on the glue spot.
    Repeat a few times for stubborn spots, avoiding components / plastic capacitor sleeves.

    Once it's soft it just peels off.
     
  19. Mr. Yamaha

    Mr. Yamaha Not so much Yamaha lately... Subscriber

    Messages:
    604
    Location:
    Amsterdam Area, The Netherlands
    I wouln't use acetone, it can damage the board and it's white lettering.
     
  20. zaibatsu

    zaibatsu Active Member

    Messages:
    441
    Have you experienced this on the B-2 board?

    Because I've done it with many Yamaha integrated and power amps and the PCB / white lettering is completely unaffected (even if you leave the acetone on it for 15-20mins), they seem to have used a solvent-resistant ink/paint. However I don't have a B-2 so I can't speak for that.
     

Share This Page