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Pioneer CT-F2121 frustration

Discussion in 'Pioneer Audio' started by Alan G., May 28, 2018.

  1. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    i recently acquired this cassette deck. Belts were shot, of course. So, I got a belt and capstan tire kit, replaced everything, cleaned and lubed it. It plays. It even rewinds. It will fast forward without a tape, but really slow, laboring, inconsistent speed with a tape.

    Anybody share that experience? What did you do?
     

     

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  2. spicer

    spicer Super Member

    Messages:
    1,090
    I've rebuilt many of those years ago. Not an easy machine to change all the rubber. Usually replaced the head as they seemed to have a high wear rate. Anyway, assuming no excess take up clutch drag or other mechanism interference, they were kind of known for needing motor replacement with those kinds of problems. We used to use generic motors which at the time cost less than five dollars... they are electronically regulated with speed adjustment through a little hole in the back plate of the motor. All motor speed regulation circuitry in inside the motor, you adjust a trim pot through hole. You might check the voltage to the motor, making sure it is okay and making it through the activation switch. The motor voltage is usually printed on the motor.
     
  3. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    Thanks. I’ll try that first. I watched a YouTube video of a guy who took apart the motor, did something to the brushes and oiled the bearings. It’s weird how the rewind works like a champ, but FF doesn’t. Uses the same idler wheel with two tires, same motor.

    By the way, I know this was an entry level unit at the time, and I’d guess the sound quality got better over the years, but at 14 lbs., silver face, actual VU meters, it’s a nice looking machine.
     
  4. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    Motor says 9VDC. I’m getting 10.23V.
     
  5. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    If it FF's really slow but, does rewind and play at appropriate speeds adjusting the the leaf spring tension for the FF might be what the problem is.
    I just replaced everything you did on a CT-F7171 which has basically the same carriage and I had to lighten the pressure on the leaf spring so it wouldn't bind up the idler and it runs fine now.
    Not having a torque gauge I just engaged the RW (with power off) and felt how tight the capstan on the left was by turning it and made the right one, while FF was engaged the same or as close as I could get it. Not saying you'll have to do this because I'm not real sure that it's doing the same as mine but, your explanation sounded like it to me.
    Working on a CT-F2121 right now and replacing the same so I know there pretty much a like, even the motor, except for the lack of a few controls.
     
  6. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    There are springs all OVER this thing! Did you lesson the tension on the center, two-tire idler by stretching the spring slightly? How did you get at it? It does seem that the idler is a little too tight against the flywheel, binding it.
     

     

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  7. spicer

    spicer Super Member

    Messages:
    1,090
    The voltage is okay... that's what it is under load, right? I forgot to say make sure of the condition of the pinch roller and pinch roller pressure... either of those can cause these problems too.. including skewing tape. And the FF function... it's been a long time but I seem to remember it has a swinging idler affair that needs to have the right tension too... seems like I remember a wire spring applies this... and it might be partially engaging in play causing problems. Yes, the 2121 was the bottom of their front loading cassette line but a solid and good looking unit. The VU meters are neat. Taking the motor apart allows one to clean the commuter of oil and carbon accumulation but it is a tricky thing to do and not something I did except fooling around because of our warranty and the cheap price of the motor. I'd find the cause of the poor fast forward before I condemned anything. Make sure the take up clutch is not too tight, that can affect tape travel through the pinch roller/capstan. As was suggested, be sure the activation leaf switch is clean and properly engaging but with a steady voltage of over 10 volts to the motor under load it should be fine.
     
  8. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    Under load, yes. I’ll try to locate and adjust whatever spring is pulling the idler onto the flywheel. Whatever pressure it is now is stopping the motor and belt from turning continuously.
     
  9. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    Here's a page from the service manual showing it. This is the under side of the deck and you'll have to remove
    part of the lower carriage to get to it but, if you've replaced all the belts you've already done this once.
    It's the part I circled. NOT the standard coil spring, the LEAF like spring under it in the pic.

    CT-F2121 leaf spring.jpg CT-F2121 leaf spring.jpg
     
    Alan G. likes this.
  10. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    Oh! and BTW, the service manual states it's a leaf switch but, technically it's not, it is not wired per say to voltages of any sort, so don't mess with the real
    leaf switches.
     
  11. spicer

    spicer Super Member

    Messages:
    1,090
    That's right about the leaf switches. The leaf spring is very touchy... seems like it works in conjunction with drive torque to pull the idler to place, must be correct to properly release idler back into position other wise it interferes with transport functions. Back at the time I used all Pioneer replacement parts except for the motor and head, seems like it was particular about having the correct tires. I forgot to mention be sure and clean any lubricant from the mechanism that might have hardened. Always clean old lubricant before adjusting anything mechanical... springs, levers, etc. After seeing so many problems caused by less than new lubricant I left them dry after cleaning unless it was a motor or capstan bushing, or an idler bushing on a reel to reel.
     
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  12. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    Hey! Thanks, guys! Now I have a project again. I figured this was a mechanical problem. Hope I can do some tweaking, and I’ll do a better job of clearing off and reapplying lubricant.
     
    Pioneered likes this.
  13. spicer

    spicer Super Member

    Messages:
    1,090
    You are welcome... and be sure to clean before tweaking... and if you reapply, be very judicious... just a little.
     
    Alan G. likes this.
  14. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    Am more then happy to be of help sir, just remember when bending that spring it won't take much, just a little pressure will do it.
    When you think you haven't bent it, that's probably enough. I tried to match the tension of the other capstan when RW was engage as I stated before.
     
    Alan G. and spicer like this.
  15. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    It will take awhile to get back to you with results. I’m completely out of those 6” q-tips. Essential! Had to order some online as the my last bunch was from Radio Shack.

    Funny how a combination of old lubricant, a metal leaf spring (do they bend, get out of whack during years of usage? No memory?) and other wear (the idler has two tires, but also a plastic cylinder) can have such an effect.

    Thanks again.
     
  16. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    I have no concrete proof but, I believe the new tires for the idlers may be a bit oversized thus making them jam against the capstan.
    And this is why it needs to be adjusted just in the slightest bit. I reckon it's better to have them a bit oversized then undersized in any event.
     

     

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  17. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    I got my belt kit from WJoe Radio that came with 4 capstan tires and certainly noticed that the idler 2 had smaller I.D.s., making them thicker than the originals. At one point I re-swapped them with the originals. No difference in FF.

    Maybe I blew it here: there’s another “idler”, all plastic, that the idler wheel pushes against the left capstan to activate RW. Its swivel action was really stiff, so I, um, sprayed a little silicone in there to loosen it. And it did. But to what detriment? During all this, play was never compromised.
     
  18. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    That's where I purchased mine and I feel that they are probably the best out there having purchased some from others that just weren't up to snuff and he supply's idlers along with them and well written instructions on how to install them properly.
    I would just make sure all contact surfaces are clean with IPA and not too shiny/slick and put the new rubber idler wheels back on and adjust the leaf spring. If all is right this should cure the problem.
    And from now on ONLY use a light oil and sparingly to pivot points and axles (for the lack of the proper word) Remember that when it's running things are spinning and throwing any excess
    oil out and onto anything near by.
     
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  19. Alan G.

    Alan G. Active Member

    Messages:
    190
    Location:
    Columbia Falls, Montana
    Update: and sorry it took so long. I took the unit apart and noticed that that leaf spring really doesn’t put any pressure on the rewind function. So, it seemed the pressure for the rewind stuff was exerted by a small spring; not the same pressure exerted by the leaf spring during FF!

    I cleaned off as much old AND new lubricant as I could and bent the leaf spring slightly to alleviate some pressure for FF. Again, Rewind works, FF is really spotty and labored. I swapped out tires for the takeup reel - twice. It just seems that the plastic idler wheel turning the takeup reel tire is not doing it. Yet the idler tires (below the plastic) are being turned okay by the big, main wheel.

    Does that make any sense? Anyway, I had to put it all back together for another time. I won’t give up. Wish I had more tires.
     
  20. Pioneered

    Pioneered Well-Known Member

    Messages:
    719
    The RW and FF have different mechanizes providing tension, correct. Did you check the tension of the of the capstan while FF was engage (power off of course)? If FF is not engaged there will be no pressure from the leaf spring on it.
    Both RW and FF capstans (those black wheels that engage the tape) should have the same tension on them when they are engaged.
    That or it may not be assemble correctly. I just got done with my 2121 without a hitch.
    I think photos would be a good idea at this point because I'm not sure if we're talking about the same thing here.
     
    Last edited: Jun 11, 2018

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