Toshiba RTS90 (play back speed)

[mark]

I’ve got two of these and both have the same problem. Main capstan motor spins fine but the take up motor spins way to fast while in PLAY.
Other issue is the humming or feedback noise while playing a cassette. I’ve read the other post regarding the issue and will try to continue where they left off.
I’ll start by replacing all the ICs on the deck, from what I understand some of them control speed and direction of the motor. Others would control music search functions….
I’m also going to replace the ICs on the “ADRES” board.
All other function on both boxes work great. AM FM, AUX
No service manual for this model regardless I will will these!!!!!

 

[Tinman]

I never had one but most players have a clutch on the take up reel.
It's possible that it's not slipping.

 

[Superduper]

Well, if you are running that 100v boombox on 120, the take up motor is going to spin very fast because it's getting more voltage than intended.

 

[mark]

Well, if you are running that 100v boombox on 120, the take up motor is going to spin very fast because it's getting more voltage than intended.

I thought of this and it still happens when I run Batteries in it. Can’t figure it out…

 

[AE_Stereo]

Main capstan motor spins fine but the take up motor spins way to fast while in PLAY.

Are you saying this without a tape?
And when there is a tape, is the take up reel pulling more than the tape that is being pushed out by capstan? Can it even do that?

Does this happen in all decks without a cassette? When there is a tape, take up reel rotates at different speed depending on the diameter of the tape reel, and the speed is adjusted by the slipping clutch.

 

[mark]

On this model there ar two motors one for the capstan and another for the take up reel. The take up reel is going way too fast for "play". same speed as FF.
I'm thinking the motor will burn out due to it struggling to pull it through the capstan pinch roller. Slipping clutch.........hmmmm definitely not slipping.

 

[Superduper]

The take up reel always spins faster than the capstan needle. It has to in order to keep tension on the tape and spool up correctly. It's the pinch roller that controls the speed and prevents the audio from sounding chipmunkish. If the take up reel didn't exert positive pressure on the tape, that's when the tape begins to feed and bunch up, when the take-up reel can't keep up. And at that point, the tape becomes lunch for the deck. Be advised that there is no service manual for the S90 and the deck circuitry uses the early 2-sided printed trace design that is so prone to deterioration. Not only are traces printed, but resistors are printed directly onto the board. You could only tell what the original design values of those resistors are by the service manual. In all my years, I've only seen 1 for sale, in Japan (of course). But I bid over $200 and got outbid. Never seen another one since. The point is that if some values have deteriorated in the printed resistors, you may never be able to restore that deck. Deteriorated traces can be fixed with jumpers. Those are far more likely to fail than the tape control ICs.

 

[mark]

The take up reel always spins faster than the capstan needle. It has to in order to keep tension on the tape and spool up correctly. It's the pinch roller that controls the speed and prevents the audio from sounding chipmunkish. If the take up reel didn't exert positive pressure on the tape, that's when the tape begins to feed and bunch up, when the take-up reel can't keep up. And at that point, the tape becomes lunch for the deck. Be advised that there is no service manual for the S90 and the deck circuitry uses the early 2-sided printed trace design that is so prone to deterioration. Not only are traces printed, but resistors are printed directly onto the board. You could only tell what the original design values of those resistors are by the service manual. In all my years, I've only seen 1 for sale, in Japan (of course). But I bid over $200 and got outbid. Never seen another one since. The point is that if some values have deteriorated in the printed resistors, you may never be able to restore that deck. Deteriorated traces can be fixed with jumpers. Those are far more likely to fail than the tape control ICs.

Thank you Superduder. When I press "Play" the take up reel is going just as fast as FF. Obviously when I have a tape in the pinch roller will slow this down but it's causing such a strain on the cassette it's "clocking" the cassette.
I've actually had five of these Toshiba RT-S90's in a hopes of getting two of them fully functional. I'm getting close....

 

[Tinman]

Is there a clutch on this?
If not, what controls the speed of the motor so it's not trying to pull the tape through the capstan and pinch roller?
Again, I've never had or seen one of these.

 

[mark]

Is there a clutch on this?
If not, what controls the speed of the motor so it's not trying to pull the tape through the capstan and pinch roller?
Again, I've never had or seen one of these.

No the take up reel doesn’t not have a clutch. The motor which powers it should run slower (less voltage) compared to FF. It’s gotta be a resistor that’s cooked

 

[mark]

I never had one but most players have a clutch on the take up reel.
It's possible that it's not slipping.

No clutch