Need help diagnosing this issue with my Tascam 388

gobbltygoop

New member
Whenever I press play or begin to fast-forward, the right side tension roller keeps doing this bumping type thing that does not sound good, it kinda sounds like incorrectly shifting a car gear mid-drive. It only does it for a few seconds then starts rolling like normal, this issue has only been happening for the last two days. Anyone know why its doing this and how I can repair it?

I have a couple videos of the issue but was unable to upload them with the format I have. Any idea how to upload iPhone videos correctly on here?

Thank you!
 
I always upload my videos to YouTube and then post a link here. Can you do that? A video would really help with understanding what you are experiencing.
 
[MENTION=202241]oldepro[/MENTION] No I don't think it was exposed to smoke or coke (lol)! I bought it a few months back and the guy had it serviced before he sold it to me, it's in pretty great condition, though now I'm noticing the first channel is recording very quietly, almost silently :facepalm: I have not taken it apart or cleaned and lubed it the innards, I'm just cleaning the heads after every use as well as the pinch roller, I have not done much research on how to.
[MENTION=137394]jamesperrett[/MENTION] I need to go back and look, I don't think it's Ampex but I'll need to confirm after work.
[MENTION=79692]sweetbeats[/MENTION] I think that is the best way, once I'm home from work I'll get the videos uploaded so I can give you guys a more accurate update!
 
[MENTION=202241]oldepro[/MENTION] Good to know, thank you. The manual says to always clean it but I kinda felt like that was BS, I'm just so afraid of screwing this thing up cuz I'd never be able to get it to a shop to get fixed.

Here are a couple of videos showing the issue I'm having (thanks [MENTION=79692]sweetbeats[/MENTION] for showing me how to upload vids!)
[MENTION=137394]jamesperrett[/MENTION] Its actually ATR Magnetics tape

YouTube

YouTube
 
There are two voltages associated with the transport. A "35v NST" supply- start voltage for the reel motors- that lasts appox.3 seconds, and a lower voltage- 24v- to run the motors. Verify all the fuses are good and the 35 volt NST supply. is good. If you have a o-scope monitor the 35v NST supply during the problem. Either way re-seat the power supply card. The problem could also be in the switching/timing circuit for the two voltages, or a unstable 35V NST supply. There was a mod.done to the power supply card that added a transistor to regulate the 35v NST supply. Pull the power supply card and see if there is a power transistor and heat sink added to the card.
 
One more thing: clean the heads every time you use it, It doesn't take much oxide to screw with the frequency response-pinch roller not so much.
 
One more thing: clean the heads every time you use it, It doesn't take much oxide to screw with the frequency response-pinch roller not so much.
Hey wkrbee! thank you for the thorough reply! I’ll be honest, I know practically nothing of what you are talking about, I’m a major newb haha. I assume I gotta go into the guts of the machine right? I have the manual as well, will that guide me through getting in there and fixing the issue, with the advice you provided?

And got it, so the heads DO need to be cleaned after every use, that's really important to know, I've been doing that except for the last couple of days, but will continue doing it with 99% alcohol and Q-tips.
 
And got it, so the heads DO need to be cleaned after every use, that's really important to know, I've been doing that except for the last couple of days, but will continue doing it with 99% alcohol and Q-tips.

With good tape they should only need to be cleaned every few hours but with old tape they'll need to be cleaned every few minutes.
 
I always follow these threads because I have several reel to reels that I'm gonna be fixing soon but rarely comment because I know little.

HOWEVER ..... I simply had to comment on what a great user name gobbltygoop is ..... I use that term ALL the time.
 
Hi!
I recently got the 388 and was hoping to diagnose a similar issue, hopefully I’m not far off on this thread for what’s happening with mine.
Here’s a short video of what it’s doing:(sorry it’s dark but it gets the point across)

The tension arms seem to not be aligned as they recommended in the manual, the right arm tends to fluctuate during playback, dipping below the optic sensor so that the clock won’t read at times, then on rewind it will bounce and as it stops it’ll pull all the way to the top.

Im guessing I need to adjust the tension arms etc? I replaced the fuses, but I’m seeing it could also be an electrical issue. Do you guys recommend a modern equivalent to the Tentelometer they call for in the manual?
Thanks!
 
Ok and here’s an example of this issue at its worst:
Does this seem to point to the electrical issue? I guess I’m in the dark without an oscilloscope or a tentelometer.
 
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