Tascam 688 stripped mech screws

Discussion in 'TASCAM Analog Forum' started by telengard, Dec 28, 2020.

  1. telengard

    telengard New Member

    Joined:
    Jan 2018
    Messages:
    19
    Likes:
    3
    Gear:
    688,424 mki,Porta 5
    I purchased a nice looking (and sold as working) 688. The mech isn't working so great, no FF/RW and Play at times starts to get backed up on the take up reel and ruins the tape.

    I took the unit apart to see if it was possibly the idler tire and it seems someone else has been in here. 2 of the 3 screws that hold the mech in place were stripped. I managed to get them out, but they are no longer usable.

    I did some searching and it seems these are called "mating" screws. They have a flat head which countersinks, then a small portion of the screw part is just a smooth shaft, then threads. It seems the threads are 3mm (not 100% sure). Below are links to pictures (I got permission denied when trying to upload). Any idea where I might get replacements or even what they're truly called?

    https://www.dropbox.com/s/8zkgw453ypxxfyz/IMG_2576.jpg?dl=0
    https://www.dropbox.com/s/ohnymfp3ilegznd/IMG_2578.jpg?dl=0
  2. Laszlo

    Laszlo New Member

    Joined:
    Jan 2019
    Messages:
    72
    Likes:
    17
    From:
    Near Budapest, Hungary
    Gear:
    Tascam Ampex Mechlabor
    Hello,
    There are tousands of different screws on Earth and they are called on the most various names. It is really a tough one to find exactly the same screw when one wants to find substitute. These kind of screws are likely used in computer hardware, I would look in scrapped older models, or also it can be a good idea simply to get into a good fastener store, and show it to a shop assistant, they will probably know what it is called and if they have it.
    BTW, the forum owner banned any pic upload to protect the storage space, and encourage members to share their images through file sharing services.
  3. SkywaveTDR

    SkywaveTDR Well-Known Member

    Joined:
    Feb 2014
    Messages:
    1,068
    Likes:
    222
    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    The place to get a screw like that might be from a guy who works on and take apart decks all the time. Most screws I have to find are located at McMaster Carr but there can be specialized screws that where custom ordered. The problem is that these screws should not fail unless one used K mart screw drivers on them. Mc Master Carr sells ISO Vessel screw drivers that fit exact to these kinds of screws they can also be called JIS drivers.
    At Teac we had all kinds of small parts and screws then the screw drawer filled up from junk that we would strip for hardware- when I threw something out there was not much going to waste. This is why I have all these reel motors for cassette deck that were barely used and would have been thrown out except I boxed them and stored them until needed. Funny how I can make money with what they would throw away- when Teac shut down I was there to collect up a lot of stuff that would have gone into the can. Some of it did when I was not there like solenoids- a 100 pound drawer of brand new solenoids never used thrown out.
  4. SkywaveTDR

    SkywaveTDR Well-Known Member

    Joined:
    Feb 2014
    Messages:
    1,068
    Likes:
    222
    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    Last edited: Dec 29, 2020
  5. telengard

    telengard New Member

    Joined:
    Jan 2018
    Messages:
    19
    Likes:
    3
    Gear:
    688,424 mki,Porta 5
    Thanks everyone for the suggestions.

    Yeah, this unit was really not treated well, stripped screws, some bent metal pieces inside. Not sure what the history of this unit is.

    I did find another unit (sold as NOT working) for donor parts. I imagine that neck is there for a reason, probably as mentioned to keep it somewhat "floating" or at least giving it slight play.

    New belt and idler tire are on the way. Had a spring pop off due to me nicking it while moving the mech to remove the reel motor and luckily still have it, just need to find out where it went. :)
  6. SkywaveTDR

    SkywaveTDR Well-Known Member

    Joined:
    Feb 2014
    Messages:
    1,068
    Likes:
    222
    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    I bought the service manual from Stereo Manuals so if you have an idea where it came from I can give you some clues. Usually when things come off they are from around what you are working with. I have had springs in unit that very never in there in the first place but they were doctoring the deck from another weakness- they often use a wrong approach.
  7. SkywaveTDR

    SkywaveTDR Well-Known Member

    Joined:
    Feb 2014
    Messages:
    1,068
    Likes:
    222
    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    OK, I was cleaning up a box of parts and found one of the flat head screws, then I went looking at some screw drawers in Bench 1 area and then found more- they are strange but not that rare as you might think. So far with a little effort I have found 6 of then so far.
  8. telengard

    telengard New Member

    Joined:
    Jan 2018
    Messages:
    19
    Likes:
    3
    Gear:
    688,424 mki,Porta 5
    I picked up a 2nd 688 which I can use for cannibalizing for parts, etc. I'll get those screws from in there. Also can probably figure out where that spring came from. :)

    thanks for your help!
  9. SkywaveTDR

    SkywaveTDR Well-Known Member

    Joined:
    Feb 2014
    Messages:
    1,068
    Likes:
    222
    From:
    Chicago area
    Gear:
    Teac, Tascam, Sony
    I would never scrap a whole unit for a few screws. I find the ones I need and usually order 100 or more of then like the 2.5mm X16mm screws I was looking for on the Tascam reel motors. McMaster Carr has them.
  10. telengard

    telengard New Member

    Joined:
    Jan 2018
    Messages:
    19
    Likes:
    3
    Gear:
    688,424 mki,Porta 5
    Oh, it was very cheap and there are many other parts in here I can utilize. This one was particular beat up physically so I don't mind using it for that purpose.