old turntables

On some types the arm touches a lever at the end of a record which then triggers a lift mechanism. Make sure that lever is free moving. Could also be problems with the arm bearings, bias compensation, or incorrect tracking weight.

Could be a jammed auto-changer trigger.

Most likely gummed up grease on any or all of those parts.

--- sam | Sci.Electronics.Repair FAQ:

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Could be wires bound up underneath or bad tonearm bearing(s)...

Mark Z.

if its an autochanger (such as a garrard or bsr), unclip the turntable's central c-ring/ clip and remove the platter itself by lifting straight up. Look for a large metal toothed cam. unclip the c-ring carefully, and lift off the cam. you may feel resistance, thus revealing the problem: gummed up due to dried grease. More importantly, there will probably be a smaller set of moving plates affixed to this cam which will need checking and removing.

I have usually found it best to remove these parts, clean the bearings and any shafts with alcohol and a q tip then regrease (NOT wd40!!). hope this helps, let us know how it all goes.

-Ben.

Could be wires bound up underneath or bad tonearm bearing(s)...

Mark Z.

I think Sam and a couple of others nailed it. Grease drys up and makes things bind. The lever which trips the 'rejuct' mech' on those old changers is definitely suspect; but I imagine the rest of the guts are just as gummy.

For a novice, these are not the easiest things to work on. The timing of the cams is similar in some ways to a VCR. Get it wrong upon reassembly, and it won't work.

jak

dallie: If you are mechanically inclined in the least, you should be able to LOOK at the mechanism under the platter and on the underside of the turntable and SEE what is hanging up. As others have indicated, could as simple as dried up grease causing stiff bearings and spindles, stuck or sluggish cam and levers, stuck end of record trigger mechanism, and possibly bent levers, etc. You should be able to move the arm around and determine what the problem is. You would be very wise to remove the expensive needle (stylus) while analysing this problem so you don't accidently damage it. If you are still not certain how to proceed with this repair you should TAKE it to a repair shop that services this type of item.... my shop does... and many smaller, owner operated shops will still do this kind of work....... if you screw it up more than it already is, the repair cost could be much higher. electricitym . .

Mechanical problem is very likely, but if not, then I would guess dried out electrolytic caps. Although there aren't as much cap problems in

If the motor runs on dc, and mechanics naturally have more "resistance" on the point where it jams, it increases the load and the ripple voltage increases on that point, and the motor doesn't get enough effective voltage to work.

This is, however, just a kind of hypothesis, and actually an unlikely reason if there isn't other symptoms (e.g. humming noise on output etc.)

Just don't disasemble beyond removing the platter. Most of the other stuff can be cleaned in-place.

--- sam | Sci.Electronics.Repair FAQ:

Important: Anything sent to the email address in the message header above is ignored unless my full name AND either lasers or electronics is included in the subject line. Or, you can contact me via the Feedback Form in the FAQs.

What? If this were an electronic problem I'd understand thinking it was a cap but this problem is totally mechanical.

I'm guessing you've never played with a turntable. There isn't a motor guiding the needle. The turntable turns and the resistance of the grooves in the record guide the needle inward. I'd have to agree with everyone else in saying that this is probably dried out grease or a mechanical failure.

- Mike

There were a few which had parallel tracking motor driven pickups. B&O and Revox, to name but two.

If you post the name and model number of the turntable, I should be able to send you a step by step repair procedure. Chuck

Dave Plowman (News) spake thus:

As the O.P. said this was a turntable from the 1960s, it is undoubtedly a simple mechanical device, with a synchronous induction motor with no associated electronics, and certainly no servo-operated tonearm. I'd be willing bet money on it.

The previous poster's (or a couple back) speculation was only that.

Oh I'd agree.

Well, yes. But where would newsgroups be without pedantry?

Very True... :-)

- Mike