Any tips on removing capacitor glue on Yamaha CX-1000? / Short rebuild thread

Discussion in 'Yamaha' started by Mr. Yamaha, May 17, 2018.

  1. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    During the recap of my CX-1000 I encountered this very stiff and cement like glue which was used to glue on larger capacitors on the main board. It doesn't come off like the other older Yamaha brown glue, which is much softer.

    Normaly I use a sharp piece of wood which doesn't scratch the PCB, but this glue is too stiff / strong. I tried with a small screw driver and already scratched the PCB :yikes:

    Does anybody has tips / experience in how to remove? Any help appreciated!

    IMG_3784.jpg IMG_3785.jpg IMG_3786.jpg
     
    mbz likes this.

     

    Please register to disable this ad.

  2. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

    Messages:
    3,963
    Location:
    Munich, Germany
    I've had some luck with acetone used repeatedly between careful work with a small blunt and rounded off flat tip screwdriver, but even then it can be extremely difficult to remove. With my CX-1 I got to the point where I decided "good enough" was good enough and gave up because I was scratching the pcb.

    Cheers,
    James
     
  3. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    Nice one on the acetone, thx James. It defenitely makes the glue softer. I used sticker remover earlier, but this works better. I'm taking every infected component out to do some proper cleaning.

    IMG_3794.jpg IMG_3795.jpg
     
    Oilmaster and Bratwurst7s like this.
  4. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    4 hours later...

    All glue gone :naughty:

    Best method: acetone and scraping with the back of a bamboo skewer stick. Made some scratches before with a screw driver, not recommended.

    IMG_3796.jpg
     
    Bratwurst7s likes this.
  5. Spiceman50

    Spiceman50 AK Subscriber Subscriber

    Messages:
    341
    Location:
    Allen Texas
    Life Hack:
    Whenever you go out for Oriental food, grab yourself some of those chop sticks. You can flatten out one edge with bench grinder, or file ... or stick one of them in a pencil sharpener to sharpen a tip on the end. Makes for easy access to cleaning various hard to reach areas or lesson damage on surfaces used to scrape.
     
    Mr. Yamaha and Bratwurst7s like this.
  6. rottalpha

    rottalpha Yamaholic Subscriber

    Messages:
    1,617
    Location:
    Middle of Crook County
    MX and CX Yamaha's have it and you should be greatful it was not the nasty Sony stuff.
    A heat gun does wonders with that glue. A bit of goof-off or acetore at the end, and is like was never there.
     
    Mr. Yamaha likes this.

     

    Please register to disable this ad.

  7. OMGCat!

    OMGCat! AK Subscriber Subscriber

    Messages:
    2,773
    Location:
    El Sereno, CA
    Heat gun is a great idea, I'll have to give that a shot next time. I've been doing the acetone and sharpened chopstick routine normally but anything to speed up the process is welcome.
     
  8. Spiceman50

    Spiceman50 AK Subscriber Subscriber

    Messages:
    341
    Location:
    Allen Texas
    It's really hard to recommend techniques for this process at least for me because as I have done it, it might not be done the same way by a reader, and damage could happen. I've sat back a little while in efforts to learn something new myself. Alas, it doesn't seem like there is a quick fast method for doing this. On my second go round, I heated up a small screw driver end, and stuck it in the middle of the glue. Let the screw driver cool down a bit, then rocked it side to side and chipped away the bulk of the glue. Then, with wood (in my case, bamboo Chop sticks), I would dip the end in Acetone and slowly and methodically, push away the remaining glue attached to the board. It was a long process to be sure. But in the end, the monotony paid off because in just about every case in my life, anytime I hurried up a process, I've damaged something. This is especially true when you start seeing the light at the end of the tunnel. All said and done, not only will you be happy with yourself for dredging though the process, you'll find you'll use less shall we say "colorful language" :D
     
    Last edited: May 20, 2018
    Mr. Yamaha likes this.
  9. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,894
    Location:
    Melbourne, Victoria
    Maybe a little off topic. Picked up a CX-1000 today, those 4 main filter caps had outer sleeves slightly receeded.
    I'm thinking of recapping the power supply only, as a precaution. It sounds decent as is. Did you find any caps
    out of spec, understand if it's a pre-emptive recap.
     
  10. rottalpha

    rottalpha Yamaholic Subscriber

    Messages:
    1,617
    Location:
    Middle of Crook County
    on an area of the size of the CX, 2-3 mins to get rid of 90%+ of the glue using a bit of heat and a wood or hard plastic stick. I used a flat metal screw driver the first time and it did not end well for the silkscreen, tried hard wood and bamboo, but my tool of choice is the I Fix it plastic tool. I use these:
    https://www.amazon.com/Universal-Sp...94&sr=8-146-spons&keywords=i+fix+it+kit&psc=1

    What usually takes longer is to clean the components, if you do not want to replace them.

    Every MX-1000 has that glue and I worked on quite a few of them. The heat-gun, hard plastic stick and a bit of acetone is what I came up with as being the most efficient method. When I have the luxury, I always replace the affected components since those take the longest to clean-up. For the MX is always a few resistors and a few diodes. It makes job substantially less painful.
     
    Last edited: May 29, 2018
    Mr. Yamaha and Oilmaster like this.
  11. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    I haven't taken the time to measure the old capacitors yet. The recap itself is a massive job. I chose to replace all electrolytics (makes me sleep well) and to resolder every solder joint. I have never seen so much cold and cracked solder joints. The caps are almost 30 years old and entry level audio grade (Elna Duorex). I tried to replace all with Silmic II's, but I couldn't find all needed values. So all audio board are being recapped with Nichicon KZ where possible, high voltage FG, ES for bipolar and KG for the large filter caps.

    Input coupling caps are being replaced with Panasonic film caps. The video / digital boards are being recapped with Nichicon PW except for the exotic short 6800 uF cap, that one is replaced with Nichicon UPA. I wil allso experiment with the input opamps. I placed DIP sockets on three inputs and start with OPA2134's and LM4562NA's.
     
    Last edited: May 22, 2018
    mbz likes this.

     

    Please register to disable this ad.

  12. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,894
    Location:
    Melbourne, Victoria
    Yes, I was surprised, still got a few to do

    Working on a CX-1 at the moment, all caps except 1 tested in spec, bit reluctant to do same on CX-1000, it's a big job like you say but agree that it will
    provide peace of mind.

    Thanks for the tip on cap selection.

    I would be very interested in this. I've used LM4562's with good results in some budget amps. May try in in the CX-1? while it's open
     
  13. Bratwurst7s

    Bratwurst7s In The Frying Pan Subscriber

    Messages:
    3,963
    Location:
    Munich, Germany
    IIRC the CD input buffer in the CX-1 is all discrete. The Phono has SIP-8 (or 9 pin) op-amps. The tape-3 is the next best input channel and also has SIP-8 op-amps in the buffer and all of the rest of the input buffers have DIP-8 op-amps. And, IIRC those SIP-8 units are low noise DD types.

    The CD and phono inputs have all 1/3w and 1w resistors in the signal path (can't recall if the Tape-3 does also) and the rest of the inputs have 1/4w.

    I wasn't expecting any real improvements after re-capping the CX-1 and was very pleasantly surprised. Replaced as many signal path caps as possible with film and the rest with Nichicon KL. Well worth the extra effort as there was a nice SQ improvement afterwards.

    LM4562/LMA49720 are great op-amps. Add a 0.1µF film cap across the supply lines (pins 4 & 8) for some extra stability.

    Cheers,
    James
     
    Mr. Yamaha and mbz like this.
  14. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    Thanks for all the tips & tricks. What works best for me: heat the glue up with my girlfriend's hair blower (due to lack of heating gun) and scrape it off with the back of a wooden chop stick. Clean afterwards with acetone. It really flies off within 2 minutes :bigok:
     
    Spiceman50 likes this.
  15. Spiceman50

    Spiceman50 AK Subscriber Subscriber

    Messages:
    341
    Location:
    Allen Texas
    Nice follow up Mr. Yamaha, appreciated. That said, another use for that chop stick I use to amaze my friends and family is how I use it to clean the USB port under the phone. I'll use the bench grinder to grind down a very fine flat end (Like a standard screw driver), and insert it into the usb plug under the phone to remove dust and dirt that collects in there from my pockets. I have the Note 8 which suffers from the dreaded Moisture detected in usb port "drama" It's caused by dust and dirt in the port. When cleaned, I'll dip the end of the wooden chop sick in a bit of Alcohol then finish up softly blowing in the port to evaporate any "Non Existent" moisture there might have been. Works like a charm.
     
    Mr. Yamaha likes this.
  16. rottalpha

    rottalpha Yamaholic Subscriber

    Messages:
    1,617
    Location:
    Middle of Crook County
    :bigok:
     

     

    Please register to disable this ad.

  17. Oilmaster

    Oilmaster Drillers go deeper Subscriber

    Messages:
    1,219
    Location:
    Paris & The Hague
    Good advice, and it would be my action as well when dealing with this rather poor opamp layout works by Yamaha.
    There is, however, a mountain of nuance on this topic.

    Some default reading to do:
    http://www.analog.com/media/en/training-seminars/tutorials/MT-101.pdf

    and for high-speed opamps (rather beyond analogue audio applications, but informative nevertheless)
    http://www.ti.com/lit/an/sloa069/sloa069.pdf

    In addition a couple of text books on that matter, leads me to rather use NP0/C0G MLCC capacitors than "film caps" for reasons of significant higher ESL for film caps.

    Secondary, such decoupling is bound to very short distance from the opamp pin to a "very low inductive ground plane" to keep inductive elements to a bare minium (or else resonance and noise are rather generated)
    And that might be the second issue for CX1000: the + and - rails are readily under the opamp of course.... but where is the ground plane (0V)?
    When long leads are required to connect the decouple caps from power rails to ground, then there is a risk of adding additional induction to the solution.

    So yes, the Yamaha PCB layout is piss poor regarding opamp decoupling, but it might be a tricky treat to improve it afterwards.
    A lot of care and knowledge required to do something that makes sense.

    EDIT: the power supply decouple caps should be between rails and ground; NOT between +/- rails !!
     
    Last edited: May 24, 2018
    Mr. Yamaha and Bratwurst7s like this.
  18. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    Thanks Oilmaster, for your wisdom :thumbsup:
     
  19. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    I wasn't planning to make a rebuild thread, but some pictures of the process / end result won't hurt :rolleyes:

    The main board:

    IMG_4083.jpg IMG_4084.jpg IMG_4085.jpg IMG_4086.jpg IMG_4087.jpg IMG_4088.jpg IMG_4089.jpg IMG_4090.jpg IMG_4091.jpg IMG_4092.jpg
     
    Last edited: Jun 1, 2018
    Spiceman50 and AsRock like this.
  20. Mr. Yamaha

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

    Messages:
    871
    Location:
    Amsterdam Area, The Netherlands
    Tone control board:

    IMG_4093.jpg IMG_4094.jpg IMG_4095.jpg IMG_4096.jpg
     
    Last edited: Jun 1, 2018

Share This Page