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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 6th Apr 2010, 7:29 pm   #1
platinum95
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Default HMV Mono Record Player Problem (Model 2004?)

Hi,
I recently found an old HMV record player in a shed, so i decided to take it home with me. When i plug it in, the turntable spins fine, and i can adjust the speed of it with no problems. However, the speaker does not come on instantly, it takes about 10 seconds for it to power up, but then after about another 5 seconds the speaker shuts off and the turntable keeps going. Then, after another few seconds, smoke starts to come out from the circuit board.I took off the panel that was convering the board and plugged it in. It seems the valves on it (there's 3) heat up fine, because there is a glow from them and that the smoke is coming from the variable resistor for the Bass. I've tried drying it out with a hairdryer and i've cleaned it out completely, but i have the same problem.

Any suggestions would be greatly appreciated.

Thanks in advance.

EDIT:
It's not the variable resistor, i removed it and there's still smoke. Now i think its the valves heating up too much and melting the board.
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Old 7th Apr 2010, 7:31 am   #2
Michael Maurice
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Default Re: HMV Mono Record Player Problem

Please do not attempt to power this machine up again.

It would be helpfull to have a model number for the record player.

Are you competent at repairing this type of equipment? If so, with a model number, we'll help you to get back to working normally.

From your description of the sequence of events, I'd guess that the record player has a valve amplifier, in which case a number of capacitors will need replacing at the very least.

Unless you are familiar with electronics and how to repair them or are willing to learn, do not attempt to repair it

I would suggest that if there are any members in Ireland who could help they contact you via the PM (Private Message) system.

Alternatively if you visit parts of mainland Britain, let us know and hopefully a member local to where you are visiting can help you out.
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Old 7th Apr 2010, 3:08 pm   #3
platinum95
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Default Re: HMV Mono Record Player Problem

First of all, thank you for your reply.

I took some pictures that might help with the understanding of the machine, but they didn't upload because there is a security token missing

The record player has no model number, its one of those HMV models that probably had some brand name. Yes there are 3 Mazda valves in it, U381, UCL83 and another but unfortunately the writing has been rubbed off.

I am not familiar with this kind of elecronics, but i understand some of the stuff in it.

My alternative is to just throw out the board in it and plug the cartridge into a stereo amp, but then I have no way of spinning the turntable. Does anyone know what voltage it would take to spin the motor?

Thanks
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Old 7th Apr 2010, 5:55 pm   #4
Jonster
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Default Re: HMV Mono Record Player Problem

Usually units like this use a mains voltage AC motor. Sometimes the motor winding acts as a tranformer for the electronics but probably not in this. If it's a three valver with separate bass and treble controls it would have been a cut above the average Dansette of the period. Please dont scrap the internals! With very little work it should be usable. Modifying it so will negate any value it has.
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Old 7th Apr 2010, 6:10 pm   #5
platinum95
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Default Re: HMV Mono Record Player Problem

yeah the motor has its own transformer, i was guessing that it was getting AC power straight from the plug.

I was thinking that it would be such a shame to scrap it, because it must be from the 70's at the very least, not that i know this is the first time i've ever had a record player.
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Old 7th Apr 2010, 7:08 pm   #6
Michael Maurice
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Default Re: HMV Mono Record Player Problem

This would date from the 1960's, by the 70's they were all transistorised.

The U381 is the rectifier and is equivalent to a a UY85, I'd be interested to know what the third one is.

The most common problems are dried up electrolytic capacitors and leaky paper/wax capacitors. Not that difficult to repair.
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Old 7th Apr 2010, 7:38 pm   #7
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Default Re: HMV Mono Record Player Problem

Yay i got the photo uploading working, so please enjoy these photos of my record player
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Old 7th Apr 2010, 8:45 pm   #8
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Default Re: HMV Mono Record Player Problem

Well looking at the third, fourth and fifth images above it seems that your main problem is that someone has removed one of the front panel controls. That probably won't help.

As Michael says, don't attempt to power it up again.
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Old 7th Apr 2010, 9:50 pm   #9
Michael Maurice
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Default Re: HMV Mono Record Player Problem

I did a bit of digging and found that the likely model number is 2004

The service data is available from this site: http://www.service-data.com/product.php/2785/3750

The third valve is another UCL83 it being a push pull output stage, with one half of the UCL's acting as first amplifier and second half as the phase splitter.

You must change C8, C10 and C11, C7, C14 & C15 are all in one can, and will need reforming or replacing.

The missing control is the bass control and is a 1M lin potentiometer.

This would have been quite a classy record player in its day, the push pull output stage would have given it more power than normally available, the separate bass and treble controls would have been somewhat luxurious in its day.

Please please please, do not discard the amplifier, if you feel that restoring is beyond your capability and you cant find anyone to restore it for you then offer it to someone who can in the sets and parts wanted section.

This player is far too good for the skip.
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Old 7th Apr 2010, 10:14 pm   #10
platinum95
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Default Re: HMV Mono Record Player Problem

Thank you all so much for all your help, i will do my best to restore it.

About the missing bass control, i removed it to see if that was the reason for the smoke, because it looked like the smoke was coming from it. I have it here and plan to reattach it very soon, when i have the time.

Again,thank you all for your help.
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Old 8th Apr 2010, 1:08 pm   #11
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Default Re: HMV Mono Record Player Problem

ok i removed all the capacitors that i was told to remove, but c8, c10 and c11 all have .01 written on them and i was wondering if that was .01 farad or .01 micro farads?
And with the can, i was wondering how i replace or reform this?

Thanks
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Old 8th Apr 2010, 2:41 pm   #12
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Default Re: HMV Mono Record Player Problem

A 0.01 Farad capacitor would be physically huge, so they're undoubtedly 0.01uF (micro farads). 10nF (nano farad) capacitors are just the same give or take the units and position of the decimal point. The replacement capacitors should be rated at the same or higher voltage as the originals.

It isn't worth your building a reformer to reform the capacitors in the can. Either connect a 60W mains filament bulb in series with the mains lead when you first apply power or replace the capacitors in the can with new individual ones under the chassis. The series lamp will limit the current which would otherwise be drawn by a short circuit can. If all is OK after a minute or so disconnect from the mains and feel the capacitor's case to see if it's getting hot. If so replace it.

If it's an HMV model 2004 the capacitors in the can will be 40uF. Replace with 47uF if necessary. 40uF units aren't easy to obtain.
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Old 8th Apr 2010, 3:22 pm   #13
platinum95
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Default Re: HMV Mono Record Player Problem

Yeah I was thinking that it couldn't be a .01 farad, but i just wanted to be sure.

Moving on to the can, how would i replace the capacitors of the can? I've attached some pictures of it. There are 2 40uf capacitors and one 8uf.

Oh and its from April of 1963 if anyone was wondering....
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Last edited by platinum95; 8th Apr 2010 at 3:46 pm.
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Old 8th Apr 2010, 4:09 pm   #14
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Default Re: HMV Mono Record Player Problem

Hopefully that can will be OK. Power up the player with a 60W filament light bulb in series with the live side of the mains (see here). If the bulb runs dim after about 5 minutes, it means the capacitors have reformed themselves; try connecting the player straight to the mains. If it shines at or near full brightness, there's a problem; in which case, you will have to replace the capacitors as follows:

Get two 47F / 350V and one 10F / 350V capacitors from your favourite supplier. Join all the negatives together, and connect to wherever in the circuit the common negative terminal came from (that'll be the 0V rail). Join the positives of the 47F capacitors to wherever the positives of the 40Fs came from (probably the cathode of the UY85 and the screen grids of the UCL83 pentodes joined together), and the positive of the 10F to wherever the positive of the 8F came from (probably the cathodes of the UCL83 pentodes joined together).

By the way: The internals of this machine (as a rule, anything using U- or P-type valves) will be at mains potential, so take great care. Note also that the capacitors connecting the pick-up cartridge to the amplifier really need to be replaced with "Class Y" parts of the same value.
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Old 8th Apr 2010, 8:18 pm   #15
platinum95
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Default Re: HMV Mono Record Player Problem

anyone know what voltage the .01uF capacitors have to be?

Last edited by platinum95; 8th Apr 2010 at 8:44 pm.
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Old 8th Apr 2010, 9:15 pm   #16
Michael Maurice
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Default Re: HMV Mono Record Player Problem

At least 300V DC, preferably 500V DC.

Dont forget, C1, C2 and C3 must be class Y types.
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Old 8th Apr 2010, 10:14 pm   #17
platinum95
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Default Re: HMV Mono Record Player Problem

sorry for my slowness, i am new to this kind of thing, but does anyone know of a good supplier for the capacitors that i need?

Last edited by platinum95; 8th Apr 2010 at 10:30 pm.
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Old 9th Apr 2010, 5:11 am   #18
Michael Maurice
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Default Re: HMV Mono Record Player Problem

Farnell: http://uk.farnell.com/

RS Components: http://uk.rs-online.com

You might require accounts to purchase from RS components.

Cricklewood Electronics: www.cricklewoodelectronics.co.uk

Maplin: www.maplin.co.uk You might find their range and stock somewhat limited.

I'm sure others will be adding to the list.
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Old 9th Apr 2010, 7:22 am   #19
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Default Re: HMV Mono Record Player Problem

Quote:
I'm sure others will be adding to the list.
See this thread for lots of supplier suggestions:

http://www.vintage-radio.net/forum/s...ghlight=maplin
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Old 9th Apr 2010, 11:41 am   #20
platinum95
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Default Re: HMV Mono Record Player Problem

Thanks

Just one more question, are they film or ceramic or whatever?
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