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Old 14th Sep 2018, 6:48 pm   #1
Dorian27
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Default Garrard to BSR

Hi I have a Gerrard deck on my old player which has had damage and no longer works I have a spare BSR deck in good condition which I want to fit I can make a plinth with no problem the only problem I have is the motor has to change and the wiring on Gerrard motor is 3 colour s Red White and Black and on the BSR I have 4 wires 2White 1Blue 1Brown how do I fix this as I have not got a clue where to go can any one help I have pics of the motors the first two are Gerrard wiring and the last bsr motor thanks
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Old 14th Sep 2018, 7:18 pm   #2
ms660
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Default Re: Gerrard to bsr

They might not be compatible, some were auto transformer some were isolating transformer, you need to be sure, make and model of the record players?

The tap (auto transformer) is often a white wire, if that's the case with the one in the first photo then it appears to be connected wrong in the second photo but I'm not absolutely sure what colour the tap wire should be on the Garrard motor, someone else might know for sure.

The two white wires on the BSR motor do suggest a separate winding.

Lawrence.

Last edited by ms660; 14th Sep 2018 at 7:29 pm. Reason: addition
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Old 14th Sep 2018, 8:00 pm   #3
Ed_Dinning
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Default Re: Gerrard to bsr

Hi Dorian, the BSR motor has the 2, white wires linked and brown and blue go to the supply. With supply only connected the deck should work (some of these decks use a switch in the white wires to stop the deck).

These white wires will be at 120v. the typical 3 wire motor would output about 85 to 90 volts for the valve heaters.
If you find out what valves are fitted and the heater current they take it is easy to calculate the additional resistance needed(which will get warm(.
One I did as few weeks ago needed a 250R 5W resistor, yours may be different.

Ed
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Old 14th Sep 2018, 8:57 pm   #4
teetoon
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Default Re: Gerrard to bsr

Hi. These motors are definately NOT compatible.
The BSR has a low voltage output on the 2 white wires to power a transistor amplifier and the Garrard will have a 90 volt tap on the red wire for valve heaters in series.
You can see in your second picture that the black motor wire connects to the live side of the switch and a dropper resistor. The white motor wire goes to the neutral side of the switch and to chassis. The red motor wire appears to connect to a thermistor which would feed the valve heaters.

The clue is in the brown and blue wires (on the BSR) being the mains colours at a much later date (1970?) and Garrard did use black and white as the mains connection on many 2 pole motors.

BSR motors with a 90 volt tap had brown and black as mains in and white as the 90 volt tap.
What did the BSR deck come out of ?

David.

Last edited by teetoon; 14th Sep 2018 at 9:10 pm. Reason: more info
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Old 14th Sep 2018, 9:26 pm   #5
julie_m
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Default Re: Gerrard to bsr

The motors look incompatible

A record player motor often serves double duty as a transformer, since it already has a bobbin and a steel laminated core. This transformer functionality is matched to the record player's amplifier. The Garrard one seems to have a tapping for valve heaters, which will put out about 90V AC between itself and one of the other 2 wires (no electrical separation, due to the connection in common) whereas the BSR one seems to have a separate winding for a transistor amplifier. It probably will be putting out about 24V AC on the white wires, when fed with 240V on the brown and blue wires.

Work-arounds would be either (a) use a resistor or capacitor voltage dropper, or (b) replace the original valve amplifier with a new IC amplifier, reusing the existing controls and speaker and leaving the original parts in situ for possible restoration in future. It might actually not be as crazy as it sounds, especially in the absence of a suitable high-output crystal cartridge. If you end up having to fit one of the "Chinesium" red stylus cartridges, which have a lower output voltage than the old crystal cartridges, then a simple UL84 won't have enough gain to give you a decent listenable volume.


Still, we can cross that bridge when we come to it. I think for now, we really need to see where the other ends of those motor wires end up.
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Old 14th Sep 2018, 10:34 pm   #6
Edward Huggins
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Default Re: Gerrard to bsr

We still don't know the type of record player you have, but I suspect that your Gerrard (sic) deck forms part of a UL84/UY85 type unit, in which case the white wire delivers a 90V tapped supply for the valve heaters.
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Old 14th Sep 2018, 11:15 pm   #7
julie_m
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Default Re: Gerrard to bsr

Never mind, I've had a better look at picture 2 and I think I can see what's happening. The neutral side of the mains switch (RH end of the photo) is connected by a thin black wire to the middle terminal on the 3-way tag strip, which goes to chassis and also connects to the white motor wire. The black motor wire goes to the live side of the mains switch (inwards from the edge) which also has a large green 100Ω resistor connected to it. The other end of the resistor goes to the right hand tag. The red motor wire goes to the left hand tag, then through a large carbon resistor to one of the valve pins. So it looks as though black is live 240V, white is the common neutral and red is the 90V heater supply output.

Is this how you're seeing it?
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Old 15th Sep 2018, 4:53 am   #8
julie_m
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Default Re: Garrard to BSR

So I made a SPICE deck:
Code:
* CAPACITIVE DROPPER FOR RECORD PLAYER VALVE HEATERS
* THE MAINS SUPPLY.  NOTE AMPLITUDE IS GIVEN AS PEAK
V1 1 0 SINE ( 0 340 50 )
* THE DROPPER CAPACITOR  (SEVERAL IN PARALLEL IF NEEDED)
C1 2 3 1u
C2 2 3 .47u
* R1 = SURGE LIMITER RESISTOR
R1 1 2 100
* R2 = BLEED RESISTOR
R2 2 3 470K
* V2 = MILLIAMMETER FOR MEASURING CURRENT
V2 3 4 DC 0
* R3 = THE VALVE HEATERS IN SERIES = 380 + 450 = 830Ω
R3 4 0 830
Then run
Code:
tran 1u 1
plot v(4) i(v2)*1000 v(3)-v(2) xlimit .5 .6
The [color=#red line represents the voltage across the valve heaters. The blue line is the current (in mA, because we are multiplying by 1000), and the oragge line is the voltage across the capacitor(s).

In other words, it seems to work just fine using a capacitance of 1.47F (=1F and 470nF in parallel) and a resistance of 100Ω in series with the valve heaters. The 470k resistor in parallel with the capacitors is there to provide a discharge path and so prevent a shock hazard from the plug pins after it is withdrawn from the wall. The capacitors should be rated for at least 400V and preferrably 630V. They will not need to be class X rated, due to the presence of a series resistance.
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Old 15th Sep 2018, 8:41 am   #9
John10b
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Default Re: Garrard to BSR

Hi Julie what is a SPICE deck?
Cheers
John
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Old 15th Sep 2018, 1:14 pm   #10
julie_m
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Default Re: Garrard to BSR

SPICE is an old, but still very useful, computer program which analyses electronic circuits mathematically. The circuit was described by a deck of punched cards, one for each component. The text file that does the same job nowadays is still sometimes fondly referred to as a "deck"; and although my first experience of SPICE was on a microcomputer, our lecturers had used the old mainframe versions with actual punched cards.

Today, there are several Open Source and Proprietary circuit simulation programs based on the original SPICE and they all accept the same circuit descriptions, whether on punched cards or on disk. Each line describes one component; it has its name (which includes what type of component it is and therefore how many pins it will have), a list of the circuit nodes to which each pin is connected (in a fixed order) and its value or parameters. Lines starting with * are comments and are ignored.

In this circuit, V1 represents the mains supply (a sine wave with zero DC offset, 340V AC peak amplitude, 50 cycles per second). R1 is a surge limiter resistor. C1 and C2 are the voltage dropping capacitors. R2 is the discharge resistor. V2 is a fixed voltage source of 0V DC, and R3 is the lumped resistance of the valve heaters (=830Ω for a UY85 and UL84). This is all just one series circuit. There is always a node 0, which is the circuit's earth. We sketch out a simple diagram, numbering nodes as we go along:

(0) ---V1--- (1) ---R1--- (2) ---C1--- (3) ---V2--- (4) ---R2--- (0)

The reason for including V2 is purely to use it as a current measurement point. (Some later SPICE versions incorporate the ability to measure current through any component, not just voltage sources; but this is a proprietary extension and not part of the original Open Source version.) We should see a peak current of 0.1414A through V2, corresponding to an RMS current of 100mA, if we have the right capacitance values between points 2 and 3.

If you download your own copy of a SPICE-based circuit simulator such as NGSPICE (Open Source) or LTSPICE (Windows only, Proprietary but 0) you should be able to feed it that input, and see whether the output looks reasonable.
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Old 15th Sep 2018, 1:43 pm   #11
John10b
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Default Re: Garrard to BSR

Thank you Julie for taking the time to explain, but I will stay away from the pc me thinks. You must think Im a bit thick but how does this help the op with sorting which wire or deck is compatible?
Cheers
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Old 15th Sep 2018, 1:57 pm   #12
julie_m
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Default Re: Garrard to BSR

It's for choosing a suitable capacitance value to use as a voltage dropper, if the original motor tapping is no longer available.
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Old 15th Sep 2018, 4:03 pm   #13
John10b
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Default Re: Garrard to BSR

Oh right thank you Julie.
Cheers
John
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Old 15th Sep 2018, 4:12 pm   #14
ms660
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Default Re: Garrard to BSR

You can also use the calc. formulas in here:

https://www.vintage-radio.com/repair...per-calcs.html

Lawrence.
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Old 15th Sep 2018, 9:27 pm   #15
Techman
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Default Re: Garrard to BSR

I would think this has now gone way over the op's head and just not worth the effort, in my opinion. Just fix the original Garrard and be done with it. It'll be a better deck anyway.
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Old 15th Sep 2018, 9:58 pm   #16
teetoon
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Default Re: Garrard to BSR

Well I'm glad someone else said it before me as I couldn't believe this had got to 14 posts for a really basic record player question.

I can only think that if the OP needs to ask about the motors and cannot measure voltages, how would they ever work out how to check a capacitive dropper was giving the correct voltage or even manage to install it ?

I know it's been said before but these RECORD PLAYER threads sound quite dangerous in the hands of a novice.

Also note in a previous thread the OP had the Garrard turntable appart and now it is broken.

I am seriously worried as to the outcome and to see how many posts yet another of these wonderful players can achieve.

Absolutely no offence meant to anyone Sorry if it sounds harsh.

Mods feel free to delete this.

David
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Old 16th Sep 2018, 12:15 am   #17
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Default Re: Garrard to BSR

The OP hasn't been back since post 3, so won't have read any of this. The motors aren't compatible, and any mods to cobble in a non-tapped motor are, as you say, over his head without assistance as he will no doubt agree.
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