Sony TC 280 slipping capstan

[onewatt]

Hi all
I have above unit which has as far as I can tell a slipping capstan. Is there a way to remedy this apart from replacing the drive wheel if indeed there available. I noticed a thread suggesting boiling in washing powder for belts does this apply to capstan drive wheels or am I being some what dim to suggest this.
Cheers
onewatt

[DOFFERY]

Check the state of the pinch wheel, if very shiny, slightly roughen, same applies to the speed transfer wheel . Make sure the flywheel & transfer wheel are clean & making good contact. There could be other problems but check the above first.

Doffery

[onewatt]

Thanks Doffrey will do.
I'm very new to tape units so appreciate the help. Regarding the pinch wheel is this supposed to be driven or does the flywheel maintain the momentum as the tape is pulled through? as it doesn't appear to get drive from any where. May be I need to do some reading up on the basic principles. Thanks again!
onewatt

[Nickthedentist]

The flywheel under the deck turns the capstan, a cylindrical metal rod, at a very precise speed.

The tape is squashed against the capstan by the rubber pinch wheel or pinch roller. The rotating capstan causes the tape to be dragged across the heads at a constant speed, and the pinch roller rotates merely because it's being turned by the capstan.

To "catch" the tape, the right-hand, take-up spool rotates clockwise, quite "feebly" because it's driven through a slippng clutch. At the start of a tape, it has to spin quite quickly, but when the take-up spool is nearly full, it runs much more slowly. It's worth repeating that the rotation of the take-up spool does NOT drag the tape past the heads, this is done purely by the capstan and the pinch roller. All it does is wind the played tape onto the t-u reel for safe keeping.

Nick.

[onewatt]

Hi Nick
Thank's for info. I've cleaned the pinch wheel and the tape is function to a point. It now seems to get faster and faster rather like a speeded up version of pinky and perky and then the next time I try it it doesn't allow the tape to move at all, so the speed is definitely not constant. I guess still capstan problem but what controls the speed of the tape?
onewatt

[DOFFERY]

Hello again, the speed is basically controlled by the transfer wheel driving the capstan/flywheel from the stepped pulley , you will see this when you change speeds, as I mentioned before clean/roughen gently the speed transfer wheel. I am assuming that the motor is OK( a common fault ,being either the motor or the capacitor)

Doffery

[onewatt]

Hi Doffrey. I've done as you suggest but what I can't see is any connection between the fly wheel on the bottom of the capstan and the rubber wheel driven off the stepped pulley. the flywheel is not being driven at the moment and I can't see why. the stepped pulley is mounted on the motor and the drivewheel driven off of it id not turning anything. I'm obviousley missing something here. I'll have another look tomorrow, Thanks again for your help.
onewatt

[onewatt]

Morning peep's
It seems the take up spool is slipping as the bottom part of the spool is rotating but not the top half under load. Common problem I guess, do I need parts or is there a fix? rewind spool is quite free running on play.
I'm still assuming the tape is pulled through between the capstan and pinch wheel by the T/U spool as it rotates and this in turn is what rotates the capstan. So! The reason for the capstan rotating is so as not to damage the tape when maintaining tension? am I kind of right??
Thanks peep's and sorry to be a nonse

[Nickthedentist]

Originally Posted by onewatt

It seems the take up spool is slipping as the bottom part of the spool is rotating but not the top half under load.

No, that sounds normal, it's the slipping clutch action to which I was referring above

[Nickthedentist]

Originally Posted by onewatt

I'm still assuming the tape is pulled through between the capstan and pinch wheel by the T/U spool as it rotates and this in turn is what rotates the capstan. So! The reason for the capstan rotating is so as not to damage the tape when maintaining tension? am I kind of right??

No!

See my last paragraph in post #4 above.

The T/U spool just avoids all your tape spilling onto the floor, nothing more, and it does not have any bearing on the tape's movement past the heads.

It's the capstan (and pinch roller) that moves the tape along at the right speed.

Nick.

[DOFFERY]

The transfer wheel is not moving perhaps seized up by the atrocious grease used on the machines,. The drive wheel is on a lever, try moving it by hand & you will see the wheel contact the flywheel, then clean the old grease off & lubricate with some light oil.Have you tried wind on/rewind? No the flywheel is driven by the rubber wheel in contact with the motor pulley & flywheel, the take up spool does just that, takes up the tape passing through the pinch wheel/capstan shaft. When you have the sped transfer wheel operating between the motor/flywheel you will be able to check the take up spool action. Until you get the drive wheel contacting with the motor/flywheel you will get nowhere.

Doffery

[onewatt]

Hi Nick and Doffrey Thanks! The water is becoming clearer Ok Nick I see what you mean regarding the clutch. its definitely the drive to the fly wheel thats not moving Doffrey, so will look at the mechanism to see why and oil. Thanks guy's for being so patient.
Onewatt
Certainly living up to my name!!

[onewatt]

Hi Nick and Doffrey. It works!!!!!!!!!!!!!!!!!!!! I removed the drive wheel and had to free off the linkage that allows the drive wheel to move sufficiently to locate on the stepped gear and the flywheel. gummed up with old grease just like you said Doffrey. Thanks again guys
Regards
onewatt

[DOFFERY]

Pleased all is well now , thanks for letting us know the results.

Doffery