slow playing reel to reel

[ScrewMP3s]

My unit is a Sony TC 352D reel to reel, i had the idler for the pinch roller "rebuilt" and it plays fine on 7 1/2 ips, but its a little slow on 3 3/4 ips and noticeably slow on 1 7/8 ips (not too awful but it is noticeable), ive cleaned the pulley on the motor and the drum at the base of the pinch roller, and there is no drag on the pinch roller either, this may be a stupid question but would the idler for the take up reel slipping make it run slowly? if not what should i try next?

also i was told to lube the bearings for the pinch roller on my Sony TC 250A deck, what do i use for lube?

 

[goanlisten]

to answer your question -

"would the idler for the take up reel slipping make it run slowly?"
yes, but not at a constant rate - i.e. it would be uneven or erratic slipping, meaning your music would sound terribly bad.

 

[goanlisten]

to answer your question -

"would the idler for the take up reel slipping make it run slowly?"
yes, but not at a constant rate - i.e. it would be uneven or erratic slipping, meaning your music would sound terribly bad.

sorry I mis-understood the question -

The take up reel merely winds the tape - it is the Capstan/idler together with the motor drive mechanism thats responsible for constant speed. So it sounds your motor or a loose drive belt might be contributing to your speed loss.

Most "non-direct motor" drive type "take up reels", use some form of slippage to control their speeds.

 

[ScrewMP3s]

the unit does not have any belts for play mode, just 2 idlers, one for teh take up reel and one for the pinch roller/capstan, i had the one for the pinch roller/capstan "rebuilt" new

 

[ScrewMP3s]

sorry, hit the wrong key, ill try again, the unit does not have any belts for play mode, just 2 idlers, one for teh take up reel and one for the pinch roller/capstan, i had the one for the pinch roller/capstan "rebuilt" (old rubber removed, new rubber installed on original idler) i did not have the one for the take up reel done, i dont believe it is the motor because at 7 1/2 ips its fine, its 3 3/4 and 1 7/8 ips when it gets slow (especially 1 7/8 ips) and these were recordings made on this unit 10 years ago so i know it wasnt always like that. i cleaned where the idlers ride and theres no drag on the pinch roller/capstan, any other ideas??? i may just send out the take up reel idler to be rebuilt and see if it makes a difference. its not painfully slow, but it is noticeable

 

[goanlisten]

sorry, hit the wrong key, ill try again, the unit does not have any belts for play mode, just 2 idlers, one for teh take up reel and one for the pinch roller/capstan, i had the one for the pinch roller/capstan "rebuilt" (old rubber removed, new rubber installed on original idler)

It sure seems the rebuilt idler is not the correct size - but fails to explain why 75ips works while the other two are off. Most (minor) idler size problems can be solved by adjusting the motor speed

How is the motor speed switched on your deck?- electrically (for example use a switch to select windings on motor) or mechanically (e.g. use of a stepped pulley/roller)?

I have an OM for TC-252 and the schematic shows no electrical switch, therefore I must conclude it's mechanical - and if that's true for your model you only have two choices: 1) use as is and live with the speed problem or 2)replace the rebuilt idler with the correct size.

Are the two idlers (take up and roller/capstan) the same size? if they are, swapping might help your cause - the take up reel speed is less critical than the roller/capstan.

good luck to you!

 

[steerpike2]

It may be the new rubber on the capstan idler is (A) too soft - meaning it adds drag to the motor, most especially when it is riding on a small diameter pulley where it experiences greatest deformation.
or (B) too hard, in which case it will slip, more so on a small diameter pulley which offers less surface area.

You could try reducing / increasing the spring presssure by which either/each idler is pushed against its drive pulley.

The size of an idler wheel - as long as it reliably contacts the two drive surfaces it connects - has no effect on the speed.

 

[kfalls]

Are there tension settings for the idlers? I work on a lot of Studer/Revox decks and speed problems are either the tensions settings of the supply and takeup motors are off, the brakes are dragging, or the pinch roller tension is not correct. Since it's OK at other speeds It's probably not the capstan itself. This looks like a pretty simple deck, so probably doesn't have a variable capstan speed control.

I'm not exactly sure how deck with idlers instead of motors work, but during playback the supply and take-up reels should provide some controlled reverse tension. Dragging brakes will increase the tension. If there is only one idler tension setting for all three speeds, the tension may be too much and is starting to overcome the torque of the capstan/pinch roller at the lowest speed. I would feel the tension at both reels during playback to see if one has more tension. I would also see how much tension is on the pinch roller by first cleaning it, then during playback slightly pull it away from the capstan to see how much pressure it takes. If it slips easily with little pressure increase the tension slightly to see if it helps.

 

[Chip Chester]

Full 7" reel of tape on the supply side or partial? If partial, what's the hub diameter? This can amplify back tension problems.

 

[oldvinyldude]

I see the SM available on HiFiEngine for the 353D model. It's likely similar enough to your 352D to assist. I suggest you create a log in there (free-and they do not spam), and get this SM. I looked at it and it's one of the clearest ones I have seen posted there!