Tascam 388 transport troubleshooting

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kslight
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Tascam 388 transport troubleshooting

Post by kslight » Sat Apr 01, 2017 1:05 pm

So seeking troubleshooting tips.


I'm having transport trouble. Basically you hit play, it engages then immediately stops. FF and RW do the same, often going "limp" after engaging (insert joke) and becoming loose in the path, coming off the guides.

Last night I had FF working, but I seem to have adjusted it to where it isn't right now.

I have been adjusting the trimmers on the reel servo PCB to the best of my knowledge (I've done this on other 388s so I know more or less what to expect).
It doesn't seem that any range of adjustment helps enough to get it to work reliably.

The behavior that is most odd is that when adjusting R112 and R212 (tension arms), they don't seem to visually move. I'm thinking this may be my problem.


What I do know...

1. Capstan belt is fine. Turns as it should, I put a new belt on just to be sure.
2. New manufacture/known good tape loaded.
3. I went to the hardware store and bought all new fuses. Behavior is unchanged.
4. I re-seated the reel servo PCB, no change.
5. When I first opened it, power supply connector "P803" was loose and at least partially disconnected. I reconnected this.
6. Tape path is clean. Was pretty goopy when I got it.
7. Swapped reel servo PCB with working machine, no change.
8. Adjusted brakes



Appreciate any ideas. I have another 388 here that I could swap stuff from if I have to..

Thanks
Last edited by kslight on Sun Apr 02, 2017 10:20 am, edited 1 time in total.

kslight
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Joined: Tue Oct 13, 2009 7:40 pm

Post by kslight » Sun Apr 02, 2017 9:31 am

So I've popped top panel off, and loaded my reel.

I've noticed that if I manually release the brakes (as opposed to hitting play) the tape will flow freely until I let go. Perhaps my brakes are locked up or not adjusted correctly? I have never had to adjust the brakes on these, any pointers?

Edit: adjusted the brakes to be uniform but did not change anything
Thanks

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Johnny Nowhere
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Post by Johnny Nowhere » Sat May 06, 2017 3:08 am

Wow, this is a month old. Have you discovered the problem or are you still struggling? The tensioner is quite likely your problem. Do you have a manual? If not, I'll be happy to guide you through the process.
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kslight
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Post by kslight » Sat May 06, 2017 1:34 pm

Johnny Nowhere wrote:Wow, this is a month old. Have you discovered the problem or are you still struggling? The tensioner is quite likely your problem. Do you have a manual? If not, I'll be happy to guide you through the process.
Still broken.

The tensioner is where I started, as that is usually the problem with these every time I have bought one. But not so lucky this time.

In further testing (I didn't bother to update this thread since no one was posting here) I concluded the reason the transport isn't working right is because the right reel motor is not turning. I measured out some points on one of the boards per someone's request and found no DC, so could be a power issue. I don't think its the motor itself, but possible.

Deeper testing procedures are above my pay grade though.

I actually today, coincidentally, hauled it off to a tech. He had another 388 sitting there too...since I have had 4 change my hands over the years, have to wonder if the other one sitting there is one of mine...lol.

Anyway, thanks for responding, but it is in someone else's skilled hands now. I feel pretty good about this tech, so I think he will get it going, or at least tell me what exactly is wrong.

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