Completely OT I know ...

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superloopy
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Completely OT I know ...

Post by superloopy »

... but from my time on the forum I know that one or two of you 'afficionados' out there enjoy tinkering with old AV equipment so I guess I'm at liberty to ask.

I have 'acquired' an old Technics system, amp, tape deck, tuner AND importantly a turntable (SL-B2, the missus wanted to blow £300 on a new one but that's not an option in my book) BUT it has speed problems, cant get it to settle or play anything with any degree of sound satisfaction for me, either too slow or too fast. I've changed the belt and stylus and now want to clean up the switches and controls inside. Question is what's the best way to do this and what equipment do i need if any. I'm supposing some type of magic spray ie contact cleaner maybe in order? Do i just whack it one every electronic 'bit' i can find? Can't betoo different to those old vintage radios i keep reading about on here, and other OT posts :-D . Any advice appreciated, between us we've loadsa 70's vinyl wich i'm glad we didn't dispose of 'back in the day'. Alongwith everything else of that era, I throw nuffin out!!

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bobins
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Re: Completely OT I know ...

Post by bobins »

I'd suggest you carefully wrap it up, put it in the post addressed to Citrojim with a note attached saying "Please fix me", then sit back and wait until it's returned in perfect working order :rofl2: :-D

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white exec
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Re: Completely OT I know ...

Post by white exec »

Don't know the details of the Technics deck you have.
Does it have a neon and timing marks on the edge of the turntable?
Assuming the belt isn't slipping, problem likely to be with the drive circuitry to the motor, assuming it's variable speed. DIrty speed control potentiometer would be first guess.

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myglaren
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Re: Completely OT I know ...

Post by myglaren »

How is the platter suspended?
Once transported a brand new Transcriptor (as seen in "Clockwork Orange")on the back seat of a Volvo, from Borås to Västerås.
The platter and tone arm are suspended in wells of oil, some of which leaked out..
Took years to get it to spin at the right speed again.

Image

Incidentally, Transcriptor was born at Michell Engineering, attached to the Vickers-Armstrong tank factory on Scotswood Road.

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CitroJim
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Re: Completely OT I know ...

Post by CitroJim »

I've not touched a record deck for possibly 30 years now. I completely abandoned vinyl when I went CD in 1985 and never looked back since...

I'd think there's something tight in there as a result of dried up grease/lubricant and a good strip and full service may resolve it. Else there may be a fault in the motor speed control regulator if it has such a device...

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white exec
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Re: Completely OT I know ...

Post by white exec »

Was a bit late last night when I read your post. Have had another look this morning.
If you Google > Images 'Technics SL-B2' and scroll down, there are lots of images of the unit and its parts, as well as Service Manual pages, and spare speed controller and other parts for sale.
Looks a very simple unit, even the speed control driving the small motor.
Edge-strobe should make speed checking easy.
Enjoy swatting the wow and flutter!

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Re: Completely OT I know ...

Post by superloopy »

Deoxit? Anyone used it?

As for 'edge strobe' ... it's all over the shop. Impossible to get it stable.

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CitroJim
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Re: Completely OT I know ...

Post by CitroJim »

xantiamanic wrote: As for 'edge strobe' ... it's all over the shop. Impossible to get it stable.
Dried/horrible old grease could well cause that by causing binding in the drivetrain. I know from vintage radio gear just how badly dried-up lubricants can cause tightness in tuning spindles and the like...

Tightness and binding could well cause the motor speed regulation to struggle...

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white exec
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Re: Completely OT I know ...

Post by white exec »

From the web photos, it's simply a small motor with pulley, driving the turntable via a large belt.
Should be easy enough to locate any stiffness.
If 'all over the place' it is either likely to be the turntable bearing, or else a poor connection/supply to the motor, or the motor itself.
Try removing the turntable and belt, and running the drive motor without anything attached.
Gently pinch the motor pulley while running, to see if the torque there is constant.

Of you have a decent multimeter, check the voltage - and the frequency - being fed to the motor, to see if they are steady. Also check the d.c. supply to the small motor speed control board.

Then send it to Jim.

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Re: Completely OT I know ...

Post by superloopy »

[emoji1][emoji1][emoji1]

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bobins
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Re: Completely OT I know ...

Post by bobins »

Don't know what the Technics run on, but on Rega's the platter spindle sits on a single ball bearing in an oil bath - and an oil change (and replacement ball bearing if you're feeling flash) is known to cure wobbly speed.

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CitroJim
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Re: Completely OT I know ...

Post by CitroJim »

white exec wrote: Then send it to Jim.
If it all gets too difficult then please do ;)

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Zelandeth
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Re: Completely OT I know ...

Post by Zelandeth »

First off take a look at the belt. I've seen them where part is more flexible than the rest causing issues.

Most likely though I would reckon is dried up old grease. With the belt off give the turntable a spin by hand, it should take a good while to coast to a halt and do so very smoothly, and obvious braking effect shows something is amiss somewhere. Given the age of the kit, dried up old grease seems highly likely though.