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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 19th Sep 2017, 2:29 pm   #1
MeanDumpsterCat
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Default Toshiba SM-3350 Running Slow

Hello everyone.
I've got a Toshiba SM-3350 music centre with a turntable that seems to be running slightly slow on both 45 and 33 RPM, just enough to be audible and shows up on a strobe test.
My first course of action is to lubricate the motor since there seems to be quite a lot of hum when the needle is on the record (not electrical hum). Can anyone recommend the best oil to use for this task and perhaps what else to check if oiling doesn't work?
It appears to be a single speed motor since the 33/45 speed is changed by a plastic arm that moves the belt to the lower section of the motor shaft. Probably a cost saving move(?)

Other than that, the system seems to be working fine (aside from a broken rewind function on the tape deck which I dont think i'll bother fixing since I hardly use it).
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Old 19th Sep 2017, 2:44 pm   #2
orbanp1
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Default Re: Toshiba SM-3350 Running Slow

Looks like hifiengine.com has a service manual for the "big brother" of this music center, the SM-3750:
https://www.hifiengine.com/manual_li.../sm-3750.shtml
There are probably lots of similarities, including the record player.

Good luck, Peter
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Old 19th Sep 2017, 2:46 pm   #3
Nickthedentist
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Default Re: Toshiba SM-3350 Running Slow

A nice unit. The cheapest in Toshiba's range of quality music centres at the time, I believe, but still a cut above what most people were buying. It has a belt-drive turntable with magnetic cartridge, decent cassette deck with Dolby B NR, and a tuner with presets. Power amp is the STK461 module ISTR.

The motor is an AC synchronous type and is fitted with a dual-diameter pulley for the two speeds as you describe. This was a very common arrangement at the time, and was used for very expensive turntables too, so you can't really describe it as a cost saving measure.

As you've guessed, I would clean and lubricate the motor bearings and the main/platter bearing too.

N.
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Old 19th Sep 2017, 2:48 pm   #4
Nickthedentist
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Default Re: Toshiba SM-3350 Running Slow

Quote:
Originally Posted by orbanp1 View Post
There are probably lots of similarities, including the record player.
I think the -3750 was a posher model with a DC servo motor driving the platter. Maybe even direct drive.
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Old 19th Sep 2017, 4:19 pm   #5
MeanDumpsterCat
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Default Re: Toshiba SM-3350 Running Slow

Quote:
Originally Posted by orbanp1 View Post
Looks like hifiengine.com has a service manual for the "big brother" of this music center, the SM-3750:
https://www.hifiengine.com/manual_li.../sm-3750.shtml
There are probably lots of similarities, including the record player.
Thanks, that does appear to be very similar to mine. I'll take a look at it

Quote:
Originally Posted by Nickthedentist View Post
As you've guessed, I would clean and lubricate the motor bearings and the main/platter bearing too.
I'm thinking some sewing machine oil will do the trick. I've used it on a couple of tape decks in the past and it worked very well.

Cheers.
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Old 19th Sep 2017, 4:40 pm   #6
Nickthedentist
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Default Re: Toshiba SM-3350 Running Slow

Yes, for the motor. But something a bit thicker for the main bearing might be better, e.g. a drop or two of engine oil.

N.
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