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Capstan Dirty after almost every playback - Tascam TSR-8.

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Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Mon Nov 23, 2020 8:27 pm

Already spoke to Hugh about this one. He said someone might be able to shine more light on this.

I've just had my Tascam TSR-8 serviced and cleaned. I made sure to clean every single part properly and bought a brand new tape, RTM tape.

I have noticed that the capstan becomes really dirty after almost EACH play threw.
I know capstans get dirty and need cleaning, but after every single play back???? This can't be right, can it?

I have no idea what the problem could be here, absolutely none, and I do experience some drop outs occasionally, I presume because of this.

Can anyone solve this one? Much appreciated.

Tar,
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Tim Gillett » Mon Nov 23, 2020 8:58 pm

Hi Bruce, is this when using the new tape? What colour is the deposit? Maybe the pinch roller rubber is disintegrating? I'm not familiar with RTM tape. Did you mean RMGI? Tim.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Mon Nov 23, 2020 9:36 pm

Hi Tim.

This is the tape, yes it is brand new - https://www.thomann.de/gb/rtm_sm911_1_2 ... ancake.htm

The colour of the deposit is like a very dark brown orangey type of colour.

When I swab with alcohol is does come off straight away, after 2 swabs, the 3rd swab comes back with no dirt on. It's just after every single play through though.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Tim Gillett » Mon Nov 23, 2020 9:52 pm

OK. Few seem to buy and use such tape these days. You might find a wider cross section of comments on a forum specifically devoted to tape such as tapeheads. Is there anything the tape contacts on the machine such as an anti scrape flutter wheel which might be shedding material? If the material deposits on the capstan shaft it will likely have also deposited on the heads and guides which would not be good.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Mon Nov 23, 2020 10:19 pm

I've heard of tapeheads, that's a good shout.

When I clean the heads, tbh, they always come back clean, never really had any massive amount of dirty coming off the heads. It is literally only the capstan that has this problem.

It's doing my nappa in! :headbang:
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Tim Gillett » Mon Nov 23, 2020 10:33 pm

If it only appears on the capstan shaft but not also on the rolling tape arm guides that is very odd.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Mon Nov 23, 2020 10:53 pm

The capstan it's self is kind of stained. Don't know if that has anything to do with it. Like all the rest of the components are really shinny silver where as the capstan is a kind of stained where the tape has passed over it.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Murray B » Mon Nov 23, 2020 11:24 pm

Important Caveat - I know nothing about reel to reel machines

Does the residue / dirt smell of anything - I'm wondering if the grease is making it's way out of the mechanisms....things can go very wrong if grease types are mixed (did you add any grease in the service?) and can it all get very oozy,

Just a thought. Feel free to ignore if this is a nonsense.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Tue Nov 24, 2020 12:01 am

Doesn't smell of anything. It is only the capstan. I imagine if the grease where to be doing that then wouldn't all the other components that the tape passes through also be covered in that same dirt? When. The heads and, the other silver bits the tape passes over, never come back with that stuff I get just off the capstan. As I say, it only requires a quick clean, but it is after every single bloody play back! I'm sure this is not normal. :think:
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby snipedog » Tue Nov 24, 2020 1:38 am

It could be possible the tension on the supply spool (or even the take up spool) is too high? This might be causing the capstan to slip on the tape as it is either held back too tightly by the supply spool, or pulled excessively hard by the take up spool.

The capstan is the only point at which the tape is "gripped" in most reel to reel machines, hence it would be the only point where oxide could be ground off the tape?

A service manual will tell you what the brake tension on the supply spool should be. Its easy to adjust on a B77, Ive never owned a TSR-8 ! S http://www.redtapemusic.net
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Tim Gillett » Tue Nov 24, 2020 1:52 am

bruceyripper wrote:The capstan it's self is kind of stained. Don't know if that has anything to do with it. Like all the rest of the components are really shinny silver where as the capstan is a kind of stained where the tape has passed over it.


From memory the steel shaft when new and clean should have a smooth, dull grey finish. After many tape passes it can collect a varnishy coating which at service I usually try to remove with believe it or not, ordinary caustic oven cleaner, careful not to let the dangerous caustic enter the capstan bearing or to accidentally get on skin or paintwork etc. I'd only suggest you do this if you have the skills to safely do it. Most users would probably leave it to the service tech.

There may also be a black rubber ring or disc located deeper in from the capstan shaft, perhaps not visible without remove some parts. I think its role is to help prevent cleaning fluid from finding its way back into the capstan bearing and washing out the lubricant. Perhaps the rubber disc has perished so badly that it has turned to goo and is mixing with your cleaning fluid and oozing out onto the visible part of the shaft. Note that I've never seen this. It's only speculation.

A correction: Earlier I suggested a perished pinch roller rubber might contaminate the capstan shaft but of course the two are normally separated by the tape so this would only occur on either side of the tape's path where the pinch roller rubber actually touches the capstan shaft.

I would try and first confirm what is the source of the muck getting onto the shaft. If the brown/orange deposit is coming from the tape you'd expect to see the same deposits on heads and guides as well as the outer roller arms. Can you play through another known good tape and see if the deposit still appears? (Be careful not to play tapes with Sticky Shed Syndrome. They can cause a lot of problems.)
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby James Perrett » Tue Nov 24, 2020 2:03 am

This does sound a little odd to me, especially as the heads remain clean - I'm just wondering if it is something to do with the pressure that the pinch roller exerts on the tape which is squeezing something out of the tape. Is the pinch roller pressure correct?

Do you have any other tape you can try? It is possible that you have a bad tape. While I've not had any trouble with the RTM tape that I've used, I have seen the odd issue reported with RTM tapes so it may be worth getting in contact with them to see what they have to say.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby Tim Gillett » Tue Nov 24, 2020 2:14 am

snipedog wrote:It could be possible the tension on the supply spool (or even the take up spool) is too high? This might be causing the capstan to slip on the tape as it is either held back too tightly by the supply spool, or pulled excessively hard by the take up spool.

The capstan is the only point at which the tape is "gripped" in most reel to reel machines, hence it would be the only point where oxide could be ground off the tape?

A service manual will tell you what the brake tension on the supply spool should be. Its easy to adjust on a B77, Ive never owned a TSR-8 ! S http://www.redtapemusic.net

That seems possible. I hadnt considered that especially after a good service. The TSR8 has fairly basic tape tensioning so slippage is most likely to occur later in the tape when the combined forces to resist pulling the tape forward increase. Once slippage occured you'd normally expect to hear pitch instability on playback.

As James says, the pinch roller pressure needs to be correct also. The pinch roller itself and its bearing needs to be in good condition with the right amount of pliability in the rubber tyre which should have retained its original shape.

Normally in my experience with these machines the tapes are pulled through by capstan and pinch roller fairly strongly. There has to be some serious lack of maintenance for the tapes to slip at the capstan. Whereas a Revox B77 with the super slow tape speeds and only 3mm dia capstan shaft is another matter altogether. Pretty much everything has to be in excellent condition for the tape to not slip.

But if the rollers including pinch roller, the two inner roller guides and the two outer roller arm guides are not rolling freely due to old dried lubricant in their plain bearings they will exert a combined resistance to the tape being pulled through as it should. I've seen many such roller bearings gummed up for this reason. Normally the bearings should be cleaned and relubricated at service, especially these days when this work may not have been performed for many years.
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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Tue Nov 24, 2020 9:34 am

Very interesting. Thanks very much. I'm going to do a bit of investigation todays and I'll reply back.

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Re: Capstan Dirty after almost every playback - Tascam TSR-8.

Postby bruceyripper » Tue Nov 24, 2020 7:06 pm

I have adjusted the tension and it seems to have made the problem slight better. However, I took the dust cap off and there are like little specs of what I presume is what is causing the stains on the capstan.

Is there anyway I can add a photo on here to show you?

- This says insert image but not entirely sure how I upload.

Or would anyone just know, is this the grease that was mentioned? Little tiny specs?

Help much appreciated.
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