Garrard Autoslim possible missing part

[thebirdman]

I've just got hold of a garrard autoslim deck to try and a record player working after having a bit of a saga with a UA14. When wired into the player, the motor is constantly going round and doesn't stop when switched off. Having managed to get a picture up on the web I can see there may be a part missing (at about 6 o'clock on the attached photo). I suspect this is a switch I might need, which would stop power to the motor when the turntable is switched off. Am I correct in this and if I am right can anyone suggest something I can make up, or does anyone have a spare (sorry if that last request puts this in the wrong area of the site)? The BSR turntables I've seen have a sort of mechanical switch operated by part of the autochanger mechanism, but from the web photo, I couldn't see how the garrard might work. Thanks again for any help. I'm still working on the UA14, but with little success

[Cobaltblue]

That deck has the filament tap for a low cost record player such as a Fidelty.

Usual arangement was a UL84 and a UY85

These had no off switch as the motor had to run constantly to feed the valve filaments.

Cheers

Mike T

[thebirdman]

I have linked it to a single valve dansette major. Does this make any difference. The motor has a white and black wire, which is what I've connected, plus a red wire that's been cut short. Do I need to do anything with that? If there's not meant to be a switch I think I might try o rig something up. Any advice gratefully received as ever.

[julie_m]

Check the resistance between each pair of wires, and apply mains to the two with the highest resistance.

The third wire should be insulated, so it can't come into contact with anything it shouldn't. The one-valve Dansettes used a nearly-proper power transformer. I say "nearly" because it had the windings laid on the same bobbin, and no earthed screening layer in between to take out the fuse if the insulation failed.

You don't really need a motor switch, in any case; record player motors should run quietly, and they won't run your electric meter down noticeably. If it is audible with no record playing, that's a sign that the bearings are in need of a spot of attention.

[thebirdman]

Thanks for the help. That makes things a lot clearer. Still might try to sort out a switch as i prefer to see the turntable stop once the turntable switch goes to off rather than keep spinning.

[jonnybear]

As far as I can remember the turntable should stop turning when in the stop position, even with the motor running, the idler should lift away from motor drive spindle.
Would think you have a sticky mechanism probably needs a little lube.?
John

[julie_m]

The turntable is supposed to stop when the changer control lever is in the "OFF" position. If it is continuing to rotate, then the rubber drive wheel is not disengaging properly; most probably just due to dried-out grease. This will be an easy fix. Pick off as much of old grease as possible with cocktail stick. Clean off rest using white spirit, apply fresh grease sparingly and reassemble.

[David G4EBT]

If your Garrard Turntable is an Autoslim 5/6 You appear to be correct in your assumption that there is a missing micro-switch as you will see from the attached pic from page 6 of the 34 page Garrard's Engineers' Service Manual'. (I've highlighted the switch and the lever that operates it). Hence, while ever the turntable is switched on, the motor will be spinning, though not necessarily the platter if the rubber 'intermediate wheel' that causes the turntable to rotate via the inside of the rim of the platter, is mechanically disengaged.

You can download the 34-page Autoslim Engineers' Service Manual and also the 15 page Instruction Manual, both of which are very helpful, F.O.C from 'The Vinyl Engine' forum, which you'll need to join, the go to the Library and enter your requirements in the search block. As with many such forums, you need to be careful that you don't unwittingly download all sorts of other stuff you'd rather not have such as tool bars and browsers.

http://www.vinylengine.com/library.shtml

You can also post help requests there as you can in this forum.

(I'm trying to get an Autoslim turntable to behave and have done everything it says in the manual in terms of cleaning and lubricating all the linkages and the turntable thrust bearing, so far to no avail).

Hope that helps a bit.

Best of luck in your efforts.

[thebirdman]

Sorry, John and AJS, I meant to say that the turntable stops , as the rubber wheel disengages ok, but the motor spindle keeps turning when the switch is at the off position. I suspect that at some stage someone has filched the switch as there are holes in the deck which might accommodate one in about the right position. I suspect I'm stuck for a replacement but have something I may be able to use from a spare dud BSR which could be used if I can't find a correct replacement. Thanks for the pointer David, I'll follow that up.

[julie_m]

There would never have been a switch in the first place, if the stator winding of the motor was used as an auto-transformer for the heater supply. The motor would have had to be powered continuously in order to keep the valves hot. It would have taken longer for them to heat up to full operation, than for the record to drop and the stylus to clear the run-in groove and reach the opening bars.

Only a changer destined to be used in a record player using a separate power supply arrangement (transformer, or dropper resistor) would have had a motor switch fitted -- although the chassis would have been designed to accommodate a motor switch if desired.

[matthewhouse]

I would have thought mains should be applied to the red and black wires, and the white wire left disconnected, but safely insulated. Do check this as AJS says, the two wires with the highest resistance reading across them is the two you need to connect to the mains. The motor will work but soon burn out if mains is shoved up the tap wire.

[thebirdman]

AJS and Mike T. I'm sure that there was no motor switch for the reasons you. What is the filament tap and is it something that needs removal before adapting to a dansette type machine (in my case an RG31) which may not need the arrangement described by Mike and AJS. I have limited knowledge but can make up a switch if I can't get hold of a Garrard one.

[D_S_J_R]

The 2 pole motor on my old 2025TC used to 'whine' quietly when running I remember. Check the flexibility of the existing wires and maybe see also if the rubber mounts can be sourced and replaced.

[julie_m]

Originally Posted by thebirdman

What is the filament tap and is it something that needs removal before adapting to a dansette type machine (in my case an RG31) which may not need the arrangement described by Mike and AJS.

The kind of motor fitted to inexpensive record players has a stator which consists of a bobbin of wire wound over a laminated steel core. Those are also the main ingredients for an auto-transformer.

An auto-transformer is a special kind of transformer with only one winding. It relies for its operation on the fact that when you have a coil of wire with a magnetisable core, the voltage is evenly distributed along the length of the coil, so that the voltage across each turn is the same. Unlike a proper transformer, an auto-transformer always has a common connection between the input and output circuits. special core ateruakBut terminal 2

Suppose we have 630 turns between terminals 1 and 2, and then a further 980 turns between terminals 2 and 3; and we apply 230 V across terminals 1 and 3. This is 230 V across a total of 1610 turns, and we know that the voltage across each turn must be the same, so we can see that we should expect to measure 90 V between terminals 1 and 2.

The armature in this kind of motor acts like the secondary winding of a transformer, and uses the energy induced in it by the stator to magnetise itself. The magnetic attraction and repulsion between the stator and armature cause the armature to revolve.

The armature robs some energy from the system, but does not affect the rule regarding even distribution of voltage; so we will still see 90 V between terminals 1 and 2 for 230 V applied between terminals 1 and 3.

This 90 volt AC supply is used to power the heaters of a UY85 and a UL84, which are about the simplest valve power supply and amplifier you can have respectively. The Dansette Major has a "proper" power transformer with electrically separate primary and secondary windings, so does not need this 90 volt tapping. If this wire is not used for anything, the end of it will become LIVE to the tune of 90 volts!, so it must be insulated.

[thebirdman]

Thanks AJS, I think I understand the principle of what you're saying. this is what I understand that I need to do. If I'm wrong please correct me.
1). With power off, Check the resistance between each pair of wires. Then apply mains to the highest resistance pair
2). Make sure the remaining wire is insulated so that it cannot zap anything or one
3) then I can connect the two mains wires to the wires from the transformer in the dansette
As I said the red wire has been cut short while white and black have been left long. I'm going to download a manual and then I'll check the pairs of wires first then come back here to see if I've got this right. Sorry for the lack of knowledge, but I'm trying to learn and it's not all that easy. One thing I have learned over the years is that electricity is extremely dangerous unless you know what you're doing, hence my caution and needing fairly simple instruction.

[julie_m]

Yes, that's exactly right.

For (2) you can push sleeving over or wrap insulating tape around the end of the wire, leaving half a cm. or so empty at the end; then fold it back on itself so as to close up the open end, and tape down.

As you are not using the tapping, you probably will find you get the least amount of power hum if you connect the mains live (red or brown wire) to the innermost end of the motor winding, and the neutral (black or blue) to the outermost end. It should be obvious which is which, just from inspection of the bobbin.

There's nothing wrong with not knowing stuff, only refusing to learn. Everyone was a beginner once. Take your time and ask questions, and there will always be someone here who can help. Before you know it, you'll be dispensing advice to a newcomer yourself

[thebirdman]

Thanks for your patience AJS. I've checked the resistance as advised, and found the greatest resistance between the white and black wires ( about 150) and less across the red and black and red and white (about 128-130ohms). So it appears that it's the white and black (as I suspected from the way the wires were cut) which need linking to the mains, and the red which should be insulated. I'll also make sure to take the advice re which to connect wrt the innermost and outmost ends of the winding. I'm always willing to learn, especially with something as potentially dangerous as electricity. My problem at the moment is that I can't sit for very long at a desk/bench due to severe back problems, so everything has to done in short bursts.

[D_S_J_R]

Sometimes, complete 4 pole motor, switch and wiring looms come up on eBay. May well be far more than you wanted to pay though, so just a suggestion. Good luck

[julie_m]

The reason for connecting the live to the inside is so that the outermost layer of the windings is close to Earth potential, and so acts as a shield to limit emission of 50 Hz.

I found this out the hard way. I had a radio / cassette player that used to hum terribly, but only sometimes ..... Eventually, I traced it to which way around the "figure of 8" power lead was plugged in.