Tascam 34B fast forward and rewind problem

[Cmrib]

Hi,

I'm new to this forum and to R2R world.

I'm trying to restore a Tascam 34B and one of the problems is tape alignment during fast or rewind at high speed.
While playing, the tape is rolled ok but at high speeds the tape on the reel become misalign and irregular.

What should I do?
Can you point me to a related thread?
I suspect the problem is related with the tape tension rollers.


Carlos

 

[A Reel Person]

In many cases that is normal.

In FF/RW the tape pack on the reel might become uneven, which is why the "tails out" regimen dictates you rewind the reel before production and wind it to the right reel entirely in Play mode before dismounting and storing the reel in tails-out orientation. It's the Play mode that will produce a nice, even, flat & tight wind on the reel. Some recorders featured a double speed "Library Wind" mode, but not on the 34B.

 

[Cmrib]

In FF/RW the tape pack on the reel might become uneven, which is why the "tails out" regimen dictates you rewind the reel before production and wind it to the right reel entirely in Play mode before dismounting and storing the reel in tails-out orientation. It's the Play mode that will produce a nice, even, flat & tight wind on the reel. Some recorders featured a double speed "Library Wind" mode, but not on the 34B.

So I can assume that the 0,8 mm gap shown on picture is normal?
Or is it missing some Teflon washes? The tape tensions rollers play a bit back and forward.
There's no exploded assembling graphic on my manual, so I don't know if there's something missing.
On other machines (AKAI) there's no moving parts.

Carlos

 

[A Reel Person]

Gap

The gap is a bit excessive. The original washers are steel. There are 2 for each roller, front & back. There is no separate part number for the washers in the 38 manual, but you may have luck getting the part (& part#) from Tascam Parts dept. You may also find the part is 3c and shipping is $7, so you may want to order several.

You may want to find/replace the washers on the tension rollers & it may close the gap a bit, but I'm not sure it will be the silver bullet you're looking for on achieving an even tape pack on fast wind. However, it can't hurt to try. I'm not sure if the washers are there for spacing or to give the roller a bearing surface that isn't the shaft or cap, respectively,... or both.

I've had many Tascam r/r recorders, although only one as factory-new, but I don't recall ever having an even tape pack on fast wind. Hence, I use tail's out on play mode. You may read on other sites that in general fast wind will not give you an even tape pack. I'm sure that's what promoted the innovation of "library wind" mode. That's MO & YMMV.

 

[jpmorris]

If I remember right from the 32, the tape pack gets even worse if the pieces of string in the tensioning mechanism snap, so you might want to check that.

 

[Cmrib]

The gap is a bit excessive. The original washers are steel. There are 2 for each roller, front & back. There is no separate part number for the washers in the 38 manual, but you may have luck getting the part (& part#) from Tascam Parts dept. You may also find the part is 3c and shipping is $7, so you may want to order several.
. )

Is there a link to Tascam parts dept?
Can I replace the steel washers by Teflon ?

Carlos

 

[A Reel Person]

...

Tascam Parts: 323-727-4840, IIRC.

I don't see any reason why you couldn't source an OTC petite Teflon washer, as long as it minimizes the gap & doesn't bind.
A little application of fine machine oil or WD40 with a swab on the shaft might be a good idea as well.

 

[quiberon]

On my 34 there is a Teflon washer above and below the tension roller. As the 34b is an upgraded 34, I think you that they should be fitted on the 34b also (Teflon NOT steel). The specs. I have for the washers on my 34 are; Inside Diameter = 3mm, Outside diameter = 5mm & thickness 0.25mm. You will need two for each roller, one above and one below, the shafts should be slightly lubricated with sewing machine oil or similar. Years ago, TEAC used to do an kit which contained motor oil and spindle oil.

 

[A Reel Person]

...

Given that the washers are very small, thin & black in color, I could be mistaken if they're Teflon & not steel. They appear to be metal, but are very thin & somewhat flexible. Most Teflon washers I've ever seen have been white. My factory original 38 still has both washers, front & back on each roller.

The 38 manual has the washers pictured & dimensions (but no separate part#),... however, I was unsure of the nomenclature & was hesitant to quote it. ...(phi)3 x (phi)6 x (tau/t).25 ... so go figure.

Thank you.

 

[Cmrib]

Thank you all guys.

Great help.

Now hard will be to find this washers locally
The Quest begins!

Two more questions for Tascam owners:
Do I need a pair of washers for the pinch roller? I think I have to put washers in all the shaft mechanisms I'm i right?

Also I have a speed problem, I have to turn the pitch all to the left and even so it is speeding some what.
The pinch roller seems to be in reasonable shape, although i have some glaze on the capstan.
The tension seems right, I tried to push the pinch roller against the capstan and the speed remain fast.
Do you think I have to dive inside and take a look at the capstan board??

Carlos

 

[quiberon]

Yes, a washer above and below the pinch roller.

Regarding the speed; the 34b runs at either 7½'' or 15'' inches per second. Could be that the tape you are playing was recorded on another deck at 3¾'' inches per second.

To adjust the capstan speed, you should use a "flutter" test tape (one for each speed) with a highly accurate 3 kHz tone and a digital frequency counter. So I wouldn't change anything on the capstan board unless it was absolutely necessary.

Test tapes are; TEAC YTT-2004(for 15 ips) and TEAC YTT-2003 (for 7½ ips), so you would need to source equivalents.

My 34's speed has never been adjusted all the time that I have owned it (around 1985 from new), and as far a my ears go the speed still sounds fine.

 

[A Reel Person]

...

I check speed during general calibration & setup with an MRL tape & frequency counter. Any of the midband frequencies are adequate to test and adjust.

 

[Cmrib]

Yes, a washer above and below the pinch roller.

Regarding the speed; the 34b runs at either 7½'' or 15'' inches per second. Could be that the tape you are playing was recorded on another deck at 3¾'' inches per second.

My 34's speed has never been adjusted all the time that I have owned it (around 1985 from new), and as far a my ears go the speed still sounds fine.

Curios enough I think it's my reference r2r that's slow. Although it seems that my Tascam is also a little speedy.
I have to find the test tapes you mentioned and check both I'm afraid.
Carlos