Tascam 34 flywheel noise/capstan motor noise + tracks not working

[artr]

Hey guys! I got my first tape deck last week, a Tascam 34. The rubber was all goo, so I changed the belt and the pinch roller. Now it plays and records alright, but has a noise, like something scraping or knocking a bit, especially apparent at 15ips. The knocking noise goes away when I lay the deck down on its back.
After researching a bit, I concluded that it might be a rubber washer inside the flywheel that´s also deteriorated, so I took the flywheel off the assembly, but now I´m unsure how to get the "shaft" in the middle out. I´ve removed the two 2mm allen scews, but it?s not really budging, and I´m a bit nervous about pulling on the part of the shaft, that drives the tape (capstan shaft I guess?), with pliers. Is this the way to do it? The flywheel spins quite freely when I hold it in my hand though, so I´m having second thoughts about my theory. Could there be any other reason for these noises in play mode, when the thing is upright, but not on its back?

Also, I wanted to test whether the flywheel was making all of the noise, so I took off the belt - and I feel that the capstan motor is a bit noisy by itself. I´ve made a little video:



you have to turn up to hear it. It´s not that bad, but my plan is to record quiet acoustic music, and I think after a few tracks, it will be audible. Is it a normal noise, and is there anything I can do to make it quieter? I also just want to know, if it´s a normal noise, because I´m anxious about ruining the motor if something´s wrong, and I just keep running it.

The tape deck was used for a bit in the 80´s, and then pretty much left alone until now. Everything is pretty sticky. Maybe the capstan motor needs oil?

 

[sweetbeats]

do not…

Disassemble the capstan or try.

There is no rubber washer in there.

With the belt removed how easy does the shaft and flywheel assembly spin in its sleeve bearing? If you can spin it and it keeps on spinning after you give it a twirl you’re not going to ruin your motor.

Do not lubricate the motor. They’re not designed to be oiled in the 30 series.

If the shaft and flywheel do not spin freely in their sleeve bearing, use a pipe cleaner or similar to clean out the bore with 91% or better iso alcohol…not sopping, just dampened. Dry it out good with some canned air. Clean the mating surface of the shaft with a lint-free rag dampened with the alcohol. Conservatively lubricator with some turbine oil. The bearing is a bronze oilite sleeve bearing that is impregnated with oil in the bronze pores, so you don’t want to go crazy with the solvent, and you should tanned to go crazy with additional oil, just enough to moisten the surfaces. Stuff can get in there and gum it up over the years.

Last thing…did you adjust the capstan thrust? Look in the manual. There is a procedure. It sets the float clearance at the back of the capstan shaft/flywheel assembly.

 

[artr]

Hey man, thanks for the reply! Gotcha no oil in the motor. The flywheel spins pretty freely when I hold it in my hand. I looked in the manual,

and this is where I´m stuck, I´ve loosened the two screws, but the capstan shaft isn´t going anywhere without a bit of violence I think.
And it only scrapes when the machine is in upright position, so I don´t think it´s scraping against the thrust plate - more likely to be against the assembly that the flywheel sits on.

 

[artr]

ok so I took out the capstan shaft from the flywheel, and there´s no rubber washer in there. The capstan thrust adjustment doesn´t change where the flywheel sits in relation to the assembly, so I think I´m going to put a nylon spacer in there and see if that helps. It should give me a bit of space between the front of the flywheel and the assembly that it´s attached to

 

[RRuskin]

A TASCAM tech told me ages ago that when a machine is upright, the capstan bearing is supporting at least in part, the weight of the motor which accelerates bearing wear. If I were you, I'd just operate your unit on its back.

 

[artr]

A TASCAM tech told me ages ago that when a machine is upright, the capstan bearing is supporting at least in part, the weight of the motor which accelerates bearing wear. If I were you, I'd just operate your unit on its back.

I will do this if I can´t solve it, but it´s just more practical upright

 

[RRuskin]

I've always found the opposite. Easier to thread tape and the only way to edit accurately.

 

[quiberon]

@artr
I had a knocking/scraping sound on my 34 a few years ago, like your 34, mine had been stood for a few years and the belt had gone to goo. The knocking sound came to light after replacing the belt, when laid on its back it was quiet.

Inside the flywheel there is/was/should be a washer with rubber attached, this rubber had turned to goo also. I replaced the rubber with a nylon spacer. To get at it you have to remove the flywheel from the capstan shaft.

After undoing the two screws on the flywheel, it should slide off the capstan, mine came off easily.

Please see this thread that I posted on Tapeheads at the time: http://www.tapeheads.net/showthread.php?t=28721

Also, see my post, (post #4) in this thread; https://homerecording.com/bbs/threa...heel-sliding-and-grinding.383022/#post4347325
Pictures attached.

 

[sweetbeats]

@artr
I had a knocking/scraping sound on my 34 a few years ago, like your 34, mine had been stood for a few years and the belt had gone to goo. The knocking sound came to light after replacing the belt, when laid on its back it was quiet.

Inside the flywheel there is/was/should be a washer with rubber attached, this rubber had turned to goo also. I replaced the rubber with a nylon spacer. To get at it you have to remove the flywheel from the capstan shaft.

After undoing the two screws on the flywheel, it should slide off the capstan, mine came off easily.

Please see this thread that I posted on Tapeheads at the time: http://www.tapeheads.net/showthread.php?t=28721

Pictures attached.

Thank you for this and I then stand corrected…I didn’t realize there was rubber bonded to one of the washers in the assembly…I assumed from the exploded view it was homogenous washer of hard material. Very helpful!

 

[artr]

@artr
I had a knocking/scraping sound on my 34 a few years ago, like your 34, mine had been stood for a few years and the belt had gone to goo. The knocking sound came to light after replacing the belt, when laid on its back it was quiet.

Inside the flywheel there is/was/should be a washer with rubber attached, this rubber had turned to goo also. I replaced the rubber with a nylon spacer. To get at it you have to remove the flywheel from the capstan shaft.

After undoing the two screws on the flywheel, it should slide off the capstan, mine came off easily.

Please see this thread that I posted on Tapeheads at the time: http://www.tapeheads.net/showthread.php?t=28721

Also, see my post, (post #4) in this thread; https://homerecording.com/bbs/threa...heel-sliding-and-grinding.383022/#post4347325
Pictures attached.

Hey quiberon, those threads were what I based my theory on - thanks a lot for posting about it, it was really helpful and detailed!
I forgot to update this thread - I opened up the flywheel and found no rubber washer at the bottom and no goo, only a normal thin metal washer. Which was strange, because it seems that several people have had the exact problem that you are describing in the threads above. I decided to put a nylon spacer inside the flywheel anyway, onto the capstan shaft, between the wheel and the little triangle that you screw onto the assembly, and with a 1,6mm spacer, the flywheel would bottom out against the thrust plate, even with capstan shaft pulled all the way into the flywheel (the capstan thrust adjustment). So I ended up removing the spacer, experimenting a bit with the capstan thrust adjustment and oiling the bearing/shaft, and I don´t really know what did it, but the knocking is gone now. Maybe the scraping was just a very dry capstan bearing, and the flywheel rubbing against the triangle piece that it sits on.

The motor is still whining a bit, and now, track 4 doesn´t work at all, and track 1 on the repro head doesn´t either, but I´m probably going to make separate thread about that after a little break. My plan was to start recording an EP on the Tascam after replacing the belt and pinch roller, but instead I just spent pretty much a week trying to get this thing to work just a bit haha. So I´m going to record a bit digitally, and then start working on it again.

Anyway, thanks a lot for the help guys, I really appreciate it!!

 

[sweetbeats]

Re-seat the amp cards. If the problems persist and they are consistent, swap cards and see if the problem follows the card. That at least narrows down if it is a problem with the amp card or something else. If the problems are NOT consistent and seem to change all the time, that usually means bad relays.

 

[artr]

Re-seat the amp cards. If the problems persist and they are consistent, swap cards and see if the problem follows the card. That at least narrows down if it is a problem with the amp card or something else. If the problems are NOT consistent and seem to change all the time, that usually means bad relays.

Sorry for being a noob, but where would I find these amp cards? I looked in the manual and couldn´t find any mention of it, this is what it looks like when I open it up from the back. Is an amp card a preamp? because this version of the 34 doesn´t have any, it only has line ins.
All tracks work on the INPUT setting.
Track 4 was actually working on the repro head before I started fixing the flywheel problem. So it might have been something I´ve done. I messed around a lot with the assembly that the heads and flywheel sit on, I tried to be careful with the wires going to the heads, but maybe something´s happened there. I opened the back up like this to look at the flywheel, but didn´t touch anything inside.

By the way sweetbeats, I recently bought a Tascam m-50, was trying to figure it out, and found a video you have on the m-520 - it helped me out a lot man! Seems like the m-50 is very similar to the one you have

 

[sweetbeats]

The M-50 is the prequel to the M-500

Series…almost identical to an M-512, but the M-50 ha 60mm throw faders instead of 100mm, and the BALANCE AMP section and backplane are different. The BALANCE AMP on the M-50 only has 2 instead of 8 channels as on the M-500 series, but on the M-50 the two channels utilize a super high headroom discrete output driver.

 

[artr]

View attachment 115578

The M-50 is the prequel to the M-500

Series…almost identical to an M-512, but the M-50 ha 60mm throw faders instead of 100mm, and the BALANCE AMP section and backplane are different. The BALANCE AMP on the M-50 only has 2 instead of 8 channels as on the M-500 series, but on the M-50 the two channels utilize a super high headroom discrete output driver.

Thanks sweetbeats, I got to the cards now. Before I start reseating and shuffling them - is there a specific way of taking them out, that results in as little PCB breaking as possible?

 

[sweetbeats]

Maybe somebody with a 30-series machine can weigh in? I’ve never pulled cards on a 30-series…only owned a 38 and a set of 32s for a short period.

 

[artr]

Maybe somebody with a 30-series machine can weigh in? I’ve never pulled cards on a 30-series…only owned a 38 and a set of 32s for a short period.

I got it now, they we´re just in there really good after 30-40 years, so it took some wiggling. I put a piece of string through the holes at the top and bottom of the card, that helped.
I reseated them, listened - playback on 4 is back. I´m not sure if it´s been gone at all - maybe I confused it with lack of record on 4 earlier. Then I swapped 1 with 2 and 3 with 4. Exactly the same result, so 4 good cards, the problem must be somewhere else. So the situation right now is:
No record/SYNC on 4
1, 2 and 3 are good
No REPRO on 1
2, 3, 4 are good.

 

[sweetbeats]

I’m assuming you’ve throughly and appropriately cleaned the entire tape path including the heads, and inspected the heads under bright light, using magnification if necessary? This is important. You could have open gaps causing the failures, or sticky shed debris on part of the heads…you’d be surprised how little debris it takes to completely null record or reproduce capability. What tape are you using?

 

[artr]

I’m assuming you’ve throughly and appropriately cleaned the entire tape path including the heads, and inspected the heads under bright light, using magnification if necessary? This is important. You could have open gaps causing the failures, or sticky shed debris on part of the heads…you’d be surprised how little debris it takes to completely null record or reproduce capability. What tape are you using?

I have cleaned the tape path well with isopropyl alcohol, and the heads too, but that was before the flywheel operation. So I´m definitely going to give the heads/tape path the cleaning of a lifetime tomorrow, to exclude that possibility completely. I´m using Maxell 35-180B

 

[sweetbeats]

Well just make sure you look at the heads under good light and with magnification if necessary. Put up a pic of the heads if you can.

Somebody else more familiar with the 30 series will need to chime in, but I know other period models of Tascam machines had muting relays mounted external to the amp cards, like on the motherboard. If those go bad that can cause signal issues, but that wouldn’t be specific to individual tracks on the heads, the relays cut the signal to the outputs when powering up to avoid the thump at the outputs.

 

[sweetbeats]

When you say no repro on 1, does that mean no signal from the sync or repro heads? And you are using a known hood recording with signal on all 4 tracks?