Page 1 of 2 1 2 LastLast
Results 1 to 10 of 13

Thread: Tascam 38 transport problems?

  1. #1
    Join Date
    Oct 2005
    Posts
    19
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0

    Question Tascam 38 transport problems?

    Sign in to disable this ad
    I've been working on my Tascam 38 for a while now attempting to get it working. I bought it a couple years ago and had it shipped to me. However it's only been in recent months that I"ve got around to actually testing/working on it. I've been having some problems but I've been able to repair many of them. However the latest one has got me stumped. First, here's what I've done so far:

    - I had to reset the height of one of the take-up reel deck as it was hitting the screw heads has the reel turned. Looks like it took a blow or fall during shipping, the back of the case has a crack. The reel now rotates without scraping.
    - I had to reseat all the channels cards as some would not pass signal. I also had to resolder the inputs on a couple of the PC boards of the DBX 150 units, as they would not pass signal either. Now I get signal/VU on all 8 channels.
    - I've replaced both the drive belt and pinch roller with parts ordered from Tascam.
    - I've throughly cleaned the heads, guides and rollers (which were pretty gunky) with S-721h. I checked the heads with a magnifiying glass and can dectect no signs of grooving or excessive wear.

    Over all the unit is very clean, except for the small crack in the back of the case incurred in shipping. I also have a copy of the owners manual.

    Here's the problem I'm having: I mounted a used reel of Ampex GM and threaded it correctly (according to users manual). I pressed play and it seemed to behave as though it was in fast forward. The heads didn't engage and the tape speed kept increasing. I tried a number of other operations, ff, rew, rec, and I'm not sure what did it, but it started working. The heads engaged and it played, but the speed seemed inconsistant. I then tried to record. Everything seemed to start properly, but after a short time the tape speed decreased and slowed to a dead stop. I noted that the take up reel tensioner arm was near the very top of it's travel. Pulling down on it, caused the tape to begin moving again. Is this tensioner arm supposed to behave like the one on the supply reel side? The tensioner arm on the supply side naturally falls to the bottom of its travel when no tape is present. The tensioner on the take-up side does not. It seems to stay where its left and won't drop unless I move it with my hand, though it doesn't seem to take much effort. It appears as though there's too much tension on the tape when in operation? The tape doesn't seem "sticky" or anything. There's also a slight squeaking from the supply reel as it plays. My best guess is that perhaps the brake on the drum is dragging and requires adjustment of some kind?

    Sorry for long post, I'm just trying to provide as much detail as possible. I'd like to know if anyone's had this or a similar problem, knows the likely cause, and perhaps the cure? I've done lots of research and found some of the common problems people have (ie loose channel cards, sticky pinch roller), but haven't seen this one yet.

    I'm REALLY looking forward to recording with this unit if I can just get it up and functioning reliably.

    Thanks in advance.

  2. #2
    Join Date
    Apr 2003
    Location
    Southern CA
    Age
    55
    Posts
    1,046
    Thanks
    0
    Thanked 1 Time in 1 Post
    Rep Power
    252142
    There's an adjustment for back-tension. Sounds like it may be set too high. I forget exactly where it is, but I'd start looking there. It should be in the manual.

    Don

  3. #3
    Join Date
    Oct 2000
    Location
    I live alone with my gear
    Age
    58
    Posts
    9,022
    Thanks
    4
    Thanked 29 Times in 24 Posts
    Rep Power
    3562768

    Arrow Hello,...

    The very first thing I'd check would be the head-load solenoid and the brake solenoid. These solenoids both have a flat rubber washer in the solenoid mechanism that's supposed to dampen the clakking noise as they engage and disengage. What happens, is that the rubber washers can become gooey in the solenoids, and prevent proper transport operation.

    Based on what you've detailed,... I'd say the heads are not loading consistently and the brakes are not disengaging consistently,... which are usually due to the rubber washer deteriorating on the solenoids.

    The fix to this problem is to (mark the inital position of the solenoids before removal), remove the solenoids from the chassis, disassemble, remove the rubber washer, clean the solenoid and replace onto the chassis. You may retrofit a generic rubber washer of the same dimensions, if it means that much to'ya, but it will run fine without them.

    You're welcome!!!
    Quote Originally Posted by Lt. Bob
    ... subtleties of sound make a difference to those who really listen.

  4. #4
    Join Date
    Apr 2003
    Location
    Southern CA
    Age
    55
    Posts
    1,046
    Thanks
    0
    Thanked 1 Time in 1 Post
    Rep Power
    252142
    Probably right. I didn't think about the possibility of aging rubber parts. The last time I looked at a 38, it was practically brand new.

    Good call, Dave.

  5. #5
    Join Date
    Oct 2000
    Location
    I live alone with my gear
    Age
    58
    Posts
    9,022
    Thanks
    4
    Thanked 29 Times in 24 Posts
    Rep Power
    3562768

    Arrow Aye!

    As well as the other DIY repairs he performed admirably, he mentioned specifically having to replace the belt and pinch roller. Then, the immediate symptoms as detailed would also lead me to believe it's the rubber in the solenoids having gone south and is preventing full and free solenoid action.

    Eh,... I've had this experience first hand on my own v'83 Tascam 38, so I know it well. Let's hope it's that simple. He's done an impressive job on DIY repairs, so far. He just needs a slight push to get over the top!

    Thanx!!
    Quote Originally Posted by Lt. Bob
    ... subtleties of sound make a difference to those who really listen.

  6. #6
    Join Date
    Aug 2001
    Location
    Illinois
    Age
    66
    Posts
    1,822
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    311243
    That sounds like the pinch roller solenoid to me but could be all or any of the ones that Reel mentioned. Good luck with your machine.

  7. #7
    Join Date
    Oct 2000
    Location
    I live alone with my gear
    Age
    58
    Posts
    9,022
    Thanks
    4
    Thanked 29 Times in 24 Posts
    Rep Power
    3562768

    Arrow Quote/Paraphrase:...

    "The tape did not seem to contact the head...
    The tape moved at an unregulated speed..."

    both are indicative of the head/load solenoid: tape not contacting head and the pinchweel not contacting the capstan.

    Then,...
    "The tape ran very slowly and the tension arm was at it's fully upmost position"...
    is indicative of the brakes not fully releasing.

    Both are issues with the solenoids, of which there is one for head/load and one for brake/release._
    Quote Originally Posted by Lt. Bob
    ... subtleties of sound make a difference to those who really listen.

  8. #8
    Join Date
    Dec 2003
    Location
    Deep down in Texas
    Age
    60
    Posts
    237
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    625
    Correct, it probably has 3 or rubber washers gummed up preventing the brake linkage and pinch-roller to engage.
    Be sure to clean each solenoid shaft very carefully so all old rubber is gone.
    Small crud left can create problems later..been there done that.
    Of course replace the drive-belt when you doing the surgery.


    Good Luck
    Vintage TX

  9. #9
    Join Date
    Dec 2003
    Location
    Deep down in Texas
    Age
    60
    Posts
    237
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    625
    After reading your post again I forgot to suggest check the right tension-roller spring, sometimes these comes off.
    And test with annother tape and see if for some reason the Ampex tape has "dry syndrom".
    Vintage TX

  10. #10
    Join Date
    Oct 2005
    Posts
    19
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Rep Power
    0
    Thank you very much for ALL of your comments and advice.

    Last night I disassembled my 38 and indeed found bad rubber washers on both the brake and head/load solenoids. The latter was in the worst condition and no longer even resembled a washer, just ring of sticky black goo. I removed the ring-clips from each solenoid and spent the remainder of the evening removing washer material and cleaning out the goo. I used several dozen cue-tips dipped in acetone to wipe away all residue from the shafts, clips, and housings. I also cycled the solenoid shafts repeatedly and kept cleaning until they stayed clean. I have not yet reassembed the unit for testing. Do the solenoid shafts require any lubrication? I'd like to replace the washers, so I'm going to stop at the hardware store after work to see if I can find a suitable replacement. I'm hoping to find a pliable silicone based washer that won't deteriorate the way rubber does. Otherwise I'll reassemble and test without them. I have only just read the last post, and did not check the right tension-roller spring, but will look at it tonight before reassembling the unit.

    Thanks again!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Tascam 22-2 problems
    By wedge in forum Analog Recording & Mixing - Tape & Gear
    Replies: 11
    Last Post: 06-25-2004, 14:09
  2. HEEEEEEEEEEEEEEEELP I'm drowning here(too many soundcards)
    By _ronin75_ in forum Digital Recording & Computers
    Replies: 16
    Last Post: 06-25-2003, 00:11
  3. Problems with a Tascam 414
    By Chris Fallen in forum TASCAM User Forum
    Replies: 0
    Last Post: 01-12-2002, 15:30
  4. Tascam 424 mkII problems
    By Boba Fett in forum TASCAM User Forum
    Replies: 4
    Last Post: 08-28-2000, 06:55

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •