Power supply to BSR UA8 deck

[Vinylrecords]

Just to be certain, as not done this before, do bsr ua8 deck motors run direct from the mains? Got 3 decks, all the wiring from the motors are different. One has two black wires (only breaking this for spares as platter and arm missing) and the one I cleaning up now has a black and brown wire running out the motor. A 3rd one I picked up a few weeks ago has red and black from the motor.

Can we confirm if this was the original wiring colours as used when the deck was manufactured? And to avoid errors, which is the LIVE wire in the black and brown arrangement. No earth wire, are these safe to run in general?

Can

[FIXITNOW]

the one I am working on is 2 black wire and 240v AC the motor should be marked with voltage ,but believe all uk ones were 240v

[Vinylrecords]

Which is the live wire with black and brown from the motor?

[Michael Maurice]

As far as I know, these decks were made to run on 240V. It doesn't matter which way they are connected.

There should be another two wires going to the switch. This was also used when wiring for 115V.

I'm confident that yours are for 240V

[Vinylrecords]

Yes, wires to the power switch are cream and green coming out the motor. So this motor can be just run from a mains plug with a 3a fuse? And with no definite live or neutral wire?

[Michael Maurice]

Correct

[goldenfleece]

Originally Posted by Michael Maurice

Correct

I assume no need to connect up any sort of general earth on this motor?

I am cannibalizing 2 other very poor condition decks to restore this one, both the others are missing many parts, but its confusing that all the 3 identical UA8 motors have different coloured wiring to both the mains feed and the power switches. I wonder if this was 'normal' in the late 50's.

[FIXITNOW]

I would earth it if just going to use with a modern amp as it's metal.

[Techman]

Be careful, they don't all run on mains 240 volts. I've got two here at the moment and one is mains and one is something like 90 volts, to be used as part of a series circuit in an old live chassis record player.

[Vinylrecords]

Originally Posted by Techman

Be careful, they don't all run on mains 240 volts. I've got two here at the moment and one is mains and one is something like 90 volts, to be used as part of a series circuit in an old live chassis record player.

The one I working on came out of a dismantled radiogram from 1957.How would I know if this was a reduced voltage motor? No markings on the motor and it looks the same as all I have seen

[Tractorfan]

Hi,
A motor with a low voltage 90 volt tapping (usually white) is used to power the valve heaters in a portable record player.
As your deck is from a radio gram, then it is unlikely to have the tap, as the valve heaters would be fed from the mains transformer. And the motor supplied from the mains via the on/off switch.
Hope this helps.
Cheers, Pete.

[Techman]

I would say that if it came out of a radiogram, then it's very likely to be normal mains. You can very easily check by comparing the DC resistance of the unknown motor against the known motor - it should be the same. A lower voltage motor will have a lower DC resistance to its windings measured on a DVM or AVO on an 'ohms' range. If there's a tapping, ie - three wires, find the highest resistance between two of them.

[Vinylrecords]

Cheers guys. I am pretty sure now it's a standard mains motor, it was just the black and brown wiring I not seen before on a UA8. I will power it up tomorrow and see how it runs.

[Techman]

Just thinking about it, you may find that a DVM won't give realistic readings, as the motor is inductive, so you'd actually need an AVO to do it. A good indication of whether the deck is mains or not would be an 'on/off' switch controlled by the start knob. No switch indicates a series with valve heaters low voltage motor - there doesn't have to be a third wire for this on these UA8 decks, or though some later ones had the 'tapping' at 90 volts, or whatever, method. They can all have the same black/brown wiring regardless of voltage.

[Vinylrecords]

Yes there is a mechanical switch connected by linkage to the start knob, the switch situated next to the motor.

[Techman]

That's good. The switch indicates that the motor only ran when the deck was operated and did not need to run continuously to keep the valve heaters in the amplifier hot, so will be a full mains type. The only possible exception would be perhaps an American version for 110/120 volt 60 Hz mains, which is very unlikely if it came from a UK gram. Old Garrards had links to change the voltage beneath the platter and a different pulley to change the frequency. These movable links either put the two motor coils in series for UK mains, or in parallel for continental/American mains. If you look closely at your BSR motor, you'll see that the two coils are in series with a supply wire going in at one side and perhaps a green wire going to the other coil and the other supply wire coming out of the other coil, indicating that they are in series. However, if it's just a low voltage motor for a series valve heater chain, then it may just have shorter wound coils still connected in series.

So to sum up - It looks like your motor is standard mains voltage because the deck incorporates that switch.

[Michael Maurice]

The motors used in UA8 could be wired for 115V.

The switch in fact connects the two coils in series, by rewiring the deck so that the coils are in parallel the motor could be used on 115V.

[Techman]

The switch sits between the two motor coils on the UA8, Michael.

As an example, the supply goes into one coil, then out to the switch, then back from the switch and into the other coil, then back out to the other supply lead. The two supply wires can be brown and black and the two coming out, one from each coil to the switch can be green and white.

There may be other variants that I haven't seen on this model of deck.

[Vinylrecords]

The UA8 is up and running, standard mains feed. Surprisingly with the original tc8m cart working well! The sound through a line input was ok, but then I bypassed the mini board of resistors and a much fuller sound resulted. Listening to a stack of old Glen Miller mono LP's, and I am surprised at the dynamic range on this antique cartridge. Not much coming through above 16-17 khz but decent bass and mids.

I was expecting a very tinny experience, but amazing sound given it's age. Speed is as near to perfect too as you could expect from one of these.

Now, all I need to decide is if it's worth all the fiddly soldering and messing to do a full stereo conversion and use all 4 tonearm wires. Hmmmmm

[Techman]

Originally Posted by Vinylrecords

Surprisingly with the original tc8m cart working well!

It must have been kept in the warm and dry.

I've actually had two of the 'S' version of this cartridge in full working condition just recently.

It looks like someone is re-manufacturing the TC8, so if it looks very clean then perhaps it's one of the 'new' ones.