Inside a Tascam 38 Capstan Motor

[Hilbert]

Hi!

This is my first post here, though I've been reading the forum for a while. I've received some real help and comfort from the inspirational posts here, so I thought I'd share something someone might find useful.

I have a Tascam 38, which I take out from the storage every once in a while. I started my recording hobby with it some 14 years ago, so it also has this nostalgic side to it...
Last time I took it out was a couple of years ago when I went through my old tapes and transferred them to the computer. The machine worked fine then. Unfortunately, this time around I found out the capstan motor had broken down. Not a very uncommon problem, as I understand (actually, the motor in my 38 was already replaced once shortly after I got the machine).

Since I mainly record to a computer, and I just wanted to have some fun with the 38, my first reaction was not to order the 250 euro spare part. Instead, I took the motor out as I wanted to see if I could do anything with it. I think I've now come to a dead end, since some parts started falling apart, but I think I actually had a shot at fixing the thing. So, I'll post the pictures I took along the way, in case someone is facing similar problems.

In my motor, the problem was that a part made out of rubber inside the motor had melted. The melted rubber had torn out one of the "arms" that were supposed to come in contact with the commutators (I hope I'm getting the terminology right). But here are the pics...

Here's the motor intact


Taking off the outer shell


There's a second cover inside


Getting to the interiors, here you can already see the commutators


This is the part that goes against the part in the previous picture. The two arms extending to the middle of the circle are supposed to come in contact with the commutators. The one starting from the top is straight, as it should be, but the one starting from the bottom is bent badly to the right. Also, a small metal piece (the "brush"?) is missing from end of the the bent arm. The backsides of the arms have pieces of rubber attached. The rubber from the bent arm has melted, and caused a mess in the commutators.


A close-up of the commutators. The black goo in the middle is the missing rubber coating missing from the previous picture. Also, you can see the missing metal piece from is stuck to the rubber mess.


So, the way I thought about it, I had two main problems. First of all, the melted rubber, and secondly, the badly bent commutator arm with the missing tip metal piece. Luckily, I was able to bend the arm to its original shape quite easily, and the metal piece was intact. The problem would be to connect it to the arm. My plan was actually to try to solder it from the back, but I didn't get a change to try this yet.

For the rubber mess, I took a box of Q-tips, and some isopropyl alcohol. I actually got it off reasonably well, but then I ran into other problems.


I guess I was applying too much pressure to the commutators, since the ring around the basis of the commutators started cracking, and seems the material is so fragile that it's just a matter of time when it all falls apart. This ring was actually holding the commutator plates in place. I didn't realize this at first. You can see the damage from the next picture. It would be nice to be able to glue the broken disk back together, but it seems too fragile, that I probably have to admit my defeat.


Hopefully this is helpful to someone, and if anyone with more experience has any advice or suggestions, I'd be happy to hear them!
I'm already looking into buying a new reel to reel machine, but I'm still ready to do a near-masochistic amount of DIY work on this baby!

 

[jeremie]

hi thanks for posting these details. I have a tascam 38 on which I replaced belt, it was gummy and falling apart. Soon after the capstan refused to work. It s hard to manually spin the motor ; I think I may have a problem with the motor as well.
glups.

 

[MagnumPI]

It looks like in "Iron Man" when he built his first suit in the cave.

 

[RRuskin]

My old sources @ TEAC/TASCAM informed me that aside from the components on the motor control board, the capstan motor in the 38 was not meant to be rebuilt. Replacement was the only option.

 

[allenh]

Tascam 38 motor repair

My old sources @ TEAC/TASCAM informed me that aside from the components on the motor control board, the capstan motor in the 38 was not meant to be rebuilt. Replacement was the only option.

Hi all I'm new here and came accross this thread when searching the net to find details of how to diagnose if the capstan motor in my 38 was faulty. And thought as this post was useful in my process I thought I would post my findings in case others might find them useful.

I've managed to repair mine, my motor didn't have any problems with the brushes as the OP's motor had but had the same problem with a burnt out component shown in the pictures going between one of the brushes and one of the terminals.

The component in question looks like a resistor but is in fact an inductor for removing noise as you would expect in a motor. It's a 2u2H part and needs to be able to handle the current draw. The originals I'm guessing are actually too small which is why they burn out.

I haven't as yet found a suitable replacement so have just linked it out with a piece of wire which is allowing the motor to work but it is a little noisy and will continue my search for a beefier one.

So for anyone with a 38 that has a dead motor as long as it still spins by hand I expect it's probabaly just this inductor that has burnt out.