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Old 2nd Feb 2017, 12:25 pm   #1
Radio_Dave
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Default Help needed restoring a Murphy V310

With virtually no experience or knowledge of televisions I'm going to try and fix up a Murphy V310, hopefully with lots of help from this forum . Please excuse any basic or simple questions!

The tube hit the faceplate when I turned it on it's face. Does it just need a good push to get it back or is there something holding it around the neck?

While the faceplate is off what the best way to clean the rubber mask that fit's around the tube?

The tube has a little scratch in the middle. It probably wont show when it's on (fingers crossed) but can it be polished out with anything?

Thanks for now,
David
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Old 2nd Feb 2017, 12:39 pm   #2
ms660
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Default Re: Help needed restoring a Murphy V310

Sounds like the CRT clamp is slack or the rubber fitted between it and the CRT has degraded.

Back in the day I used to clean the mask with warm soapy water.

Mild scratches can usually be polished out with some abrasive paste, can't remember what we used for sure but jeweler's rouge rings a bell.

Lawrence.
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Old 2nd Feb 2017, 1:24 pm   #3
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Default Re: Help needed restoring a Murphy V310

Nice receivers from Murphy and probably their most remembered.
Take care when placing the receiver on it's face. The LOPT is an oil filled can that leaks badly causing oil to run into the mask. It can be salvaged with care but don't worry too much about that at the moment.

Refrain from cleaning anything but check that the voltage selector carousel is set for 240V AC. It works loose and can twist round to DC and blow the internal fuse.

Nothing really nasty other than a large number of waxies and small IF decoupling capacitors [depending on type fitted] Do not 'blanket' change!

Two versions were produced. The original version used the Mazda 30P4 as a self oscillating line output valve. Murphy had problems with slight line drift and requested more close tolerance specification 30P4's. Mazda produced the 30P4MR, better but the problem was not cured completely until the circuit was redesigned with the addition of a 6/30L2 separate line oscillator as will be found in later models.

The Mazda CRM172 usually holds up well unlike it's 21" big brother the CRM212 employed in the V320.

Good luck with it. Plenty of help on here. Regards, John.
PS. Snip off the mains filter capacitor before you apply the mains...They go POP and frighten the life outer yer!
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Old 2nd Feb 2017, 1:49 pm   #4
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Default Re: Help needed restoring a Murphy V310

Thanks for the replies
Quote:
Originally Posted by ms660 View Post
Back in the day I used to clean the mask with warm soapy water.
What type of soap would that be? I once had a disaster washing an old turntable mat in washing up liquid. It started to rot within a week!

Quote:
Originally Posted by Heatercathodeshort View Post
Refrain from cleaning anything but check that the voltage selector carousel is set for 240V AC. It works loose and can twist round to DC and blow the internal fuse.
Opps, I've just spent the morning cleaning it. It's full of smelly oil and soot.

Quote:
Two versions were produced. The original version used the Mazda 30P4 as a self oscillating line output valve. Murphy had problems with slight line drift and requested more close tolerance specification 30P4's. Mazda produced the 30P4MR, better but the problem was not cured completely until the circuit was redesigned with the addition of a 6/30L2 separate line oscillator as will be found in later models.
I've counted 15 valves which match the number shown in the Trader Sheet 1361/T156.

Thanks
David
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Old 2nd Feb 2017, 1:52 pm   #5
ms660
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Default Re: Help needed restoring a Murphy V310

I've no idea what kind of soap we used, it was at least 40 years ago, a gentle soap I guess.

EDIT: There's a manual here:

https://frank.pocnet.net/instruments...urphy_V310.pdf

Lawrence.

Last edited by ms660; 2nd Feb 2017 at 2:00 pm.
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Old 2nd Feb 2017, 4:23 pm   #6
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Default Re: Help needed restoring a Murphy V310

Fairy liquid is fine. The only reason I don't like cleaning before testing is that you can put all sorts of man made faults on the chassis and upset adjustments. It worked as it is so I tend to leave the cleaning till well into the restoration.

With 15 valves it appears you have the early version. J.
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Old 3rd Feb 2017, 4:02 am   #7
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Default Re: Help needed restoring a Murphy V310

Toothpaste will polish glass marks but it takes a long time even with a Dremel and mop.
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Old 3rd Feb 2017, 9:38 am   #8
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Default Re: Help needed restoring a Murphy V310

My advice for what its worth, leave it well alone. The glass is VERY hard and difficult to polish. Scrub any dirt out of the scratch with a nail brush and dry with a tissue. Any unnecessary strain on the face plate of a 60 year old tube is to be avoided. You will not see it when viewing.
Get it working first and worry about the minor matters later. With care and the right approach it should be a good restoration.
Wish you were closer to me so that I could help you to carry out the early stages. John,
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Old 3rd Feb 2017, 11:55 am   #9
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Default Re: Help needed restoring a Murphy V310

Yes, after I cleaned the scratches with T-Cut I can hardly see them.

The scratches were caused by the tube flopping about against the faceplate (is that the right word?) with soot as an abrasive.

The faceplate (or whatever it is) has matching scratches too so, later on, I might try something more aggressive on that. I've done some searching on Google and cerium oxide seems to be the thing to use on scratched glass.

Oh and I found another valve last night, hiding behind the fuses, so the total is now 16 which must make it the later version

Regards
David
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Old 4th Feb 2017, 1:11 am   #10
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Default Re: Help needed restoring a Murphy V310

That will be the 6/30L2 line oscillator. J.
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Old 7th Feb 2017, 10:42 am   #11
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Default Re: Help needed restoring a Murphy V310

I might have done something silly.

I've been reading old threads about checking the oil level in the LOPTx. It seemed like a good idea to check mine, so I used a piece of wire as a dipstick. As I pushed it through the filler hole it felt like I passed through something a bit "crunchy".

Is there any chance I could have poked the wire through the windings ? Does anybody know what the insides of this LOPTx looks like?

TIA
David
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Old 7th Feb 2017, 3:55 pm   #12
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Default Re: Help needed restoring a Murphy V310

You are supposed to dip something in to check the oil level, a toothpick will do fine.

Isn't there a special hole in the LOPT case for monitoring the oil level on these models?
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Old 7th Feb 2017, 5:43 pm   #13
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Default Re: Help needed restoring a Murphy V310

I would suggest you get some signs of life on this chassis before you poke bits of wire into the LOPT.
I Might sound a bit harsh but you may well destroy parts that are almost impossible to obtain. All these minor problems will sort themselves out during the early work when powered. Take care. John.
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Old 31st Aug 2018, 2:16 pm   #14
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Default Re: Help needed restoring a Murphy V310

Thread reopened at OP's request.
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Old 31st Aug 2018, 2:55 pm   #15
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Default Re: Help needed restoring a Murphy V310

Apologies for taking so long to come back but after a lot of component changing and twiddling I've finally got the tube to light up and show a picture. I know it's not brilliant but I'm dead chuffed!

This is the first time I've used a 405 line telly and an aurora so please don't be afraid to give basic, simple answers

The picture, to me, seems dim and lacks contrast. Turning the contrast up (assuming clockwise is up) breaks up the picture.

The aurora is producing a testcard but isn't it supposed to produce an audible tone as well? All I get is a phut phut phut sound, like a distant lawnmower!

Any advise much appreciated


Thanks
David
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Old 31st Aug 2018, 4:10 pm   #16
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Default Re: Help needed restoring a Murphy V310

If the picture balloons as you increase brightness, it may be low V9 eht rectifier U26.
Not knowing the HT voltage, if thats low suggests that if the original metal rectifier is fitted
it might be a bit tired, easily replaced with a silicon diode.
Sound problem may be decoupling, have you tried injecting audio across the volume control to check the audio amplifier ?
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Old 31st Aug 2018, 4:15 pm   #17
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Default Re: Help needed restoring a Murphy V310

I wouldn't worry about the sound issue at this stage.

That's an unusual test card (to me, at least). The default Aurora test card for the UK 405 line versions of it, is Test Card C. Or are you feeding a 625 line video signal into the Aurora?

Assuming you have the correct UK 405 line Aurora version, the picture looks too wide and tall (overscanned). That might be due to low EHT.

Is the mains adjustment set correctly? If my memory is correct, it's the large clear plastic disc at the rear of the chassis. You slacken the central knob and rotate it to align with the required mains voltage.
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Old 31st Aug 2018, 5:09 pm   #18
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Default Re: Help needed restoring a Murphy V310

From memory the HT voltage was around 195V, just slightly down on the 205V that's specified. The voltage to the LOPT was low at 415V, not 475V.

For some reason the heater for the U26 wouldn't light up so I replaced it with a TV20 rectifier.

I brought the aurora second hand so I guess somebody's changed the test card?

Again from memory one of the pots around the back (Frame Lin) is very intermittent and needs a good clean. At the moment just tapping it effects the picture height


Thanks
David
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Old 31st Aug 2018, 5:43 pm   #19
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Default Re: Help needed restoring a Murphy V310

Unless they have already been changed to modern plastic film dielectric types, I would replace any wax capacitors that are connected to:

the control grid of the output section 30FL1 audio output valve V10b (C86, 0.1uF),

the control grid (g1) of the 30P4 line output valve V13 (C108, 0.01uF),

the control grid of the 30FL1 sync separator valve V7a (C59, 0.1uF),

the grid of the frame oscillator stage valve (V11b, 6/30L2), and

the control grid of the 30P12 (or 30P16) frame output valve V12 (C93, 0.1uF).

Capacitor references are those used in the official Murphy Radio V310 service manual.

If they are very leaky (highly likely), they will greatly upset the operation of these stages.

As has already been mentioned, there were several mods to this set's circuit over the course of its production, especially in the self-oscillating line output stage. In some V310 sets, the self-oscillating line output circuit was changed to add an additional line oscillator valve stage to drive the 30P4 (an official Murphy mod, to overcome line oscillator frequency drift). Note that, the V310F (the "fringe area" version of the V310) had a flywheel line sync controlled line oscillator valve stage. You set isn't a V310F, is it?

Last edited by dazzlevision; 31st Aug 2018 at 5:59 pm.
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Old 31st Aug 2018, 6:26 pm   #20
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Default Re: Help needed restoring a Murphy V310

Yes, all those capacitors have been changed. It is just a V310, the later model with an extra valve behind the fuses.

Can somebody explain what ballooning is? I tried google but it was hopeless

Regards
David
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