BSR UA25 record deck - UK Vintage Radio Repair and Restoration Discussion Forum

112stereo · 26th Apr 2016, 4:10 pm

Can anyone please advise me on a voltage issue I have.
Just acquired a Bush RP 50 record player with a UA 25 deck.
The deck is a total write off, the tone arm is broken and the deck is so rusty it's all seized. I don't know how it got in this state as the amp and cabinet are in virtually perfect condition.
I have decided to change the deck for a Garrard SP25 which I salvaged from a radiogram with woodworm.
I have cut the template and fitted it into the cabinet, all good so far, now the tricky bit. The Garrard doesn't have the 90volt to drive the two valve heaters, I am thinking about fitting a mains dropper resistor of suitable quality other than that could I use the transformer section of the drive motor from the BSR deck?
The drive part of the motor was seized solid, I have now freed it, but will no longer run without being noisy.
Hears my issue, if I can mount the motor securely can i use it as a transformer without the spindle and bearings to run just the valve heaters ?
If anyone can help I would be greatful.

slidertogrid · 26th Apr 2016, 5:16 pm

I wouldn't fit a mains dropper to replace the motor as it would get quite hot. I am not sure the motor windings would be happy running without the armature fitted if that is what you mean, they could run hot.
Some record players just strung the valve heaters in series with the mains winding of the gram motor. It's a horrible idea IMHO but seems to work.
The best way to do it would be to fit a mains transformer for the heaters. you could replace the valves with their E series equivalents parallel wire the heaters and then use a 6.3V transformer.
Rich.

Edward Huggins · 26th Apr 2016, 5:22 pm

It's a valid idea to use the motor just as a 90V source. You'll need to take the Rotor/Brearings out and secure it. I can't remember if there was a small fan blade on the motor, so check for overheating. There may be parts you can salvage from the UA25 and sell - e.g. platter. You will need c.4/5 grams tracking weight set on the Garrard's tubular tone arm and allow space for the counter-weight overhang at the rear. Edward

Clydeuk · 26th Apr 2016, 6:06 pm

I've tried this years ago to power a small i.c. amplifier from a record player without the deck. I was just starting out at the time and had no meter etc.

My findings were that without the armature installed in the motor housing it became too hot to touch after a very short period of time, the tape covering the windings also started to go dark so it ws clearly not happy. When I refitted the armature normal service was resumed.

I think you will need to find another way to get your 90 volt supply unfortunately.

julie_m · 26th Apr 2016, 7:53 pm

The motor probably won't be happy without its armature. It might make an OK transformer (with fairly lousy regulation) if the shading rings were cut off, but that would ruin it for ever working as a motor again. Depends whether the OP is willing to sacrifice it in the name of a scientific experiment .....

There certainly existed Autoslim variants with a 90V heater tapping, and the SP25 is little more than another variation on the same theme, so maybe a replacement motor could be found with the correct autotransformer tapping that will fit the deck.

An ECL82, a transformer rated 6V at at least 6 VA, a 1N4007 diode and a 220 ohm, 5 watt resistor would enable most of the original circuitry to be retained. A tape recorder which is mechanically BER would yield an ECL82 along with a suitable transformer and rectifier, giving you the option of a proper isolated supply. (All tape recorders need isolated power supplies, as they are intended to be connected to other equipment.)

You could even fit an IC amplifier and suitable power supply, although by this stage the poor record player is getting a bit like Trigger's broom .....

peter_sol · 26th Apr 2016, 10:02 pm

I have a suitable transformer, an ECL82 and an EZ80 which you could have FOC
Would you be able to modify it?

Heatercathodeshort · 27th Apr 2016, 8:25 am

The motor idea is nasty and potentially dangerous from an overheating aspect. The mains dropper is even worse! Seems a shame to waste such a nice deck in a low Fi player of this type. Better to modify the amp as suggested for 6.3v valves or better still take up Peter's generous offer. The counterweight might be a problem as mentioned and the acoustics of the RP50 box that is very poor, may not cope with the improved ECL82 amp. Just my thoughts. John.

Edward Huggins · 27th Apr 2016, 12:09 pm

On reflaction, and to preserve the integrity of the Bush RP60, a replacement BSR deck is the answer - UA14, UA15 or UA25 - they all had a 90V tap. A Garrard SP25 is somewhat wasted in this to be sure as well as the countreweight overhang. Edward

Clydeuk · 27th Apr 2016, 1:49 pm

I think the OP is using the SP25 as they already had this deck from a scrap unit. The options seem to be either to find a Garrard autoslim motor with a 90v tap, obtain another BSR deck (the original motor with the tap could be used in this case, substituting the armature and bearings if the replacement deck doesn't have the tap), find a 90v transformer, or modify the amplifier to use E series valves.

Of these options I would be inclined to find another BSR deck, there must be plenty around which will do the job.

slidertogrid · 27th Apr 2016, 2:22 pm

I think I have an autoslim in the loft if you want to go down the motor swap route let me know and I will dig it out to see if it has a 90v tapping on the motor. if so you can have it for the cost of the postage.
regards
Rich.

julie_m · 27th Apr 2016, 2:31 pm

Quote:

Originally Posted by Edward Huggins

a replacement BSR deck is the answer - UA14, UA15 or UA25 - they all had a 90V tap.

Not necessarily! Those motors were available untapped for record players with a transformer-fed amplifier, and (later) with an overwinding for record players with a transistor amplifier, as well as in an oddball version designed to wire directly in series with the valve heaters.

Though if the replacement BSR changer has the wrong motor, the existing one can be swapped in easily enough, so this isn't really a big deal.

Clydeuk · 27th Apr 2016, 2:59 pm

The later C109 and similar BSR decks could also be an option, the stepped pulley is different but the armature can be fitted to the old UA25 motor housing and this will fit the later deck fine. I remember experimenting this way years ago when trying to build a disco console from old record players.

26th Apr 2016, 4:10 pm	#1
112stereo Pentode Join Date: Jan 2014 Location: St Albans, Hertfordshire, UK. Posts: 215	BSR UA25 record deck Can anyone please advise me on a voltage issue I have. Just acquired a Bush RP 50 record player with a UA 25 deck. The deck is a total write off, the tone arm is broken and the deck is so rusty it's all seized. I don't know how it got in this state as the amp and cabinet are in virtually perfect condition. I have decided to change the deck for a Garrard SP25 which I salvaged from a radiogram with woodworm. I have cut the template and fitted it into the cabinet, all good so far, now the tricky bit. The Garrard doesn't have the 90volt to drive the two valve heaters, I am thinking about fitting a mains dropper resistor of suitable quality other than that could I use the transformer section of the drive motor from the BSR deck? The drive part of the motor was seized solid, I have now freed it, but will no longer run without being noisy. Hears my issue, if I can mount the motor securely can i use it as a transformer without the spindle and bearings to run just the valve heaters ? If anyone can help I would be greatful.

26th Apr 2016, 5:16 pm	#2
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: Bsr ua25 record deck I wouldn't fit a mains dropper to replace the motor as it would get quite hot. I am not sure the motor windings would be happy running without the armature fitted if that is what you mean, they could run hot. Some record players just strung the valve heaters in series with the mains winding of the gram motor. It's a horrible idea IMHO but seems to work. The best way to do it would be to fit a mains transformer for the heaters. you could replace the valves with their E series equivalents parallel wire the heaters and then use a 6.3V transformer. Rich. __________________ The rotation of the earth really makes my day...

26th Apr 2016, 5:22 pm	#3
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,340	Re: Bsr ua25 record deck It's a valid idea to use the motor just as a 90V source. You'll need to take the Rotor/Brearings out and secure it. I can't remember if there was a small fan blade on the motor, so check for overheating. There may be parts you can salvage from the UA25 and sell - e.g. platter. You will need c.4/5 grams tracking weight set on the Garrard's tubular tone arm and allow space for the counter-weight overhang at the rear. Edward

26th Apr 2016, 6:06 pm	#4
Clydeuk Hexode Join Date: Mar 2012 Location: Liverpool, Merseyside, UK. Posts: 453	Re: BSR UA25 record deck I've tried this years ago to power a small i.c. amplifier from a record player without the deck. I was just starting out at the time and had no meter etc. My findings were that without the armature installed in the motor housing it became too hot to touch after a very short period of time, the tape covering the windings also started to go dark so it ws clearly not happy. When I refitted the armature normal service was resumed. I think you will need to find another way to get your 90 volt supply unfortunately.

26th Apr 2016, 7:53 pm	#5
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: BSR UA25 record deck The motor probably won't be happy without its armature. It might make an OK transformer (with fairly lousy regulation) if the shading rings were cut off, but that would ruin it for ever working as a motor again. Depends whether the OP is willing to sacrifice it in the name of a scientific experiment ..... There certainly existed Autoslim variants with a 90V heater tapping, and the SP25 is little more than another variation on the same theme, so maybe a replacement motor could be found with the correct autotransformer tapping that will fit the deck. An ECL82, a transformer rated 6V at at least 6 VA, a 1N4007 diode and a 220 ohm, 5 watt resistor would enable most of the original circuitry to be retained. A tape recorder which is mechanically BER would yield an ECL82 along with a suitable transformer and rectifier, giving you the option of a proper isolated supply. (All tape recorders need isolated power supplies, as they are intended to be connected to other equipment.) You could even fit an IC amplifier and suitable power supply, although by this stage the poor record player is getting a bit like Trigger's broom ..... __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

26th Apr 2016, 10:02 pm	#6
peter_sol Octode Join Date: Aug 2003 Location: Welwyn Garden City, Herts. UK. Posts: 1,906	Re: BSR UA25 record deck I have a suitable transformer, an ECL82 and an EZ80 which you could have FOC Would you be able to modify it? Last edited by peter_sol; 26th Apr 2016 at 10:08 pm.

27th Apr 2016, 8:25 am	#7
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: BSR UA25 record deck The motor idea is nasty and potentially dangerous from an overheating aspect. The mains dropper is even worse! Seems a shame to waste such a nice deck in a low Fi player of this type. Better to modify the amp as suggested for 6.3v valves or better still take up Peter's generous offer. The counterweight might be a problem as mentioned and the acoustics of the RP50 box that is very poor, may not cope with the improved ECL82 amp. Just my thoughts. John.

27th Apr 2016, 12:09 pm	#8
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,340	Re: BSR UA25 record deck On reflaction, and to preserve the integrity of the Bush RP60, a replacement BSR deck is the answer - UA14, UA15 or UA25 - they all had a 90V tap. A Garrard SP25 is somewhat wasted in this to be sure as well as the countreweight overhang. Edward

27th Apr 2016, 1:49 pm	#9
Clydeuk Hexode Join Date: Mar 2012 Location: Liverpool, Merseyside, UK. Posts: 453	Re: BSR UA25 record deck I think the OP is using the SP25 as they already had this deck from a scrap unit. The options seem to be either to find a Garrard autoslim motor with a 90v tap, obtain another BSR deck (the original motor with the tap could be used in this case, substituting the armature and bearings if the replacement deck doesn't have the tap), find a 90v transformer, or modify the amplifier to use E series valves. Of these options I would be inclined to find another BSR deck, there must be plenty around which will do the job.

27th Apr 2016, 2:22 pm	#10
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: BSR UA25 record deck I think I have an autoslim in the loft if you want to go down the motor swap route let me know and I will dig it out to see if it has a 90v tapping on the motor. if so you can have it for the cost of the postage. regards Rich. __________________ The rotation of the earth really makes my day...

27th Apr 2016, 2:59 pm	#12
Clydeuk Hexode Join Date: Mar 2012 Location: Liverpool, Merseyside, UK. Posts: 453	Re: BSR UA25 record deck The later C109 and similar BSR decks could also be an option, the stepped pulley is different but the armature can be fitted to the old UA25 motor housing and this will fit the later deck fine. I remember experimenting this way years ago when trying to build a disco console from old record players.