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Old 8th Nov 2020, 8:26 am   #1
em536716
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Default Murphy V114 Saga

Good morning to all,

I would first like to say that I’m very bad at keeping my project progress up to date on this forum however I’m quite passionate with this one so I will try my best efforts to keep this thread ongoing, until the project is complete.

This story starts out just a few weeks after the first lockdown. A Murphy V114 popped up on the Facebook Marketplace for a few bob and I just had to have it. The cabinet was in a dreadful state along with the chassis which appeared to be covered in rust, and to no ones surprise, was missing its back cover, which allowed certain coils and chokes of the like to go walkies - however I had to have this, so I went and collected it.

To my surprise the mains transformer was actually fully functional, but the wiring going to all the valve base pins and around the chassis was all too far gone, along with this, and near enough all wire wound controls being open in various spots, I knew this would be a hell of a challenge. The original Mazda Tube was long gone, and what appeared to be a Mullard MW-22 type tube with ion trap bodged in its place.

At first I guess I wanted to try and rebuild this from the ground up, but as I’m sure anyone who’s worked on one of these before, they are a money pit of dud valves and the like, I was a little disheartened from it.

I was told by Mike Barker that the Cabinet and Chassis was of the first iteration of the V114 which is increasingly rarer than the ones which others hold in their collection, but I guess the final nail in the coffin was the fact that a couple of the RF transformers were open circuit on one side of each winding...

It was at this point that a second much better condition popped up. A friend on a local Facebook page posted about this being quite local at a car boot sale, however someone bought it before he had a chance! It subsequently ended up on eBay, and well, the chap who was selling it lives in Guilford a few minutes away from my house, so I just had to, right?

So here I am now stuck with 2 of these things, but boy was I excited. The cabinet was in fantastic shape for its age, and the chassis didn’t look touched! Did I mention that the back cover came with this one too?

Anyway, the Mazda Tube which was quite obviously the original straight gun type was very tired, but I was excited to start work on my new toy.

To save everyone having to read mountains worth’s of paragraphs I’ll try and simplify what’s happened with it, and where I’m at now!

All smoothing caps reformed nicely, and faults appeared straight away. No frame scan and lack of line scan! Frame scan came to life after cleaning the hold control, along with addressing an open wire wound height pot.

The line scan has and still is being quite a pain. I started this restoration with changing all the capacitors in the timebases with Russian parts. I know this sounds a little silly but I’m a true believer on quality and these NOS components have stood the test of time, and fit quite well in this restoration.

There were quite a few high resistors, which were duly changed in the timebases too - but alas, I still wasn’t getting the proper amplitude needed to fill my screen.

It was at this point that the heater decided to go open on my CR Tube! Heart broken, I went on a search for another one, but as I’m sure everyone on here knows, CRM92 and similar tubes are hard to come by, and harder to come by with good emission!

It is at this point that (you’ll never guess) another V114 came up on the Facebook marketplace!

This one, was missing it’s back cover, and now as I have it here, has been very molested, with RS smoothies everywhere and paralleled resistors. But hey, it has a good Brimar C9a!!

So now I have 3 of these things...

Back to the restoration, so now I have a happy tube, but not a lot of line scan, and not that much vision going on in the RF section. I had already replaced all the EF91s and the detector diodes, but but alas there’s more work to be done. The contrast control has an open part of its track. Whilst not great, I can see something that looks like a testcard!

But back to the line stage. Voltages on the anodes of the line osc and cathodes respectively were not right at all. As I stated earlier, I’ve changed a bunch of of spec resistors, and as I had started to doubt myself, double checked my work.

It didn’t click straight away, but what I appeared to be looking at was the effect of what happens when a valve doesn’t conduct - and then it clicked. The line whistle was noticeably quieter than the frame timebase frequency. It’s quite clear that the Pen 46 valve wasn’t reaching its true output peak.

So there we go. A new contrast control and a full set of good testing valves is now what I’ll be after, and we’ll try again and see how the set works with these new components. Fingers crossed.


Here are pictures of the cabinet which I’ve treated and coated in some dye, and polish. I’m not really fond of touching the cabs on things I work on but I’d thought I’d give this one a go. Also attached is a few photos of the set.
Give me your thoughts!
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Old 8th Nov 2020, 8:29 am   #2
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Default Re: Murphy V114 Saga

Here’s a few more photos...
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Old 8th Nov 2020, 9:00 am   #3
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Default Re: Murphy V114 Saga

Here’s the RF chassis
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Old 8th Nov 2020, 1:38 pm   #4
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Default Re: Murphy V114 Saga

Hi Em,
Thanks for going to the trouble to do an extensive write up- makes for good reading!
That chassis looks like it's built like a tank- but then I suppose Murphy stuff usually was. I like the wiring loom all done with lacing cord. Even the symmetrical layout of the valves at the top of the chassis looks like it's been thought about!

I've never come across one of these- let alone three! What are the chances of that? At least you should have enough bits to make one good one!

I see the cabinet has that touch of Murphy weirdness with the overlapping bit at the top round the tube.

I can't comment about the electronic side of things as it's not a set I know, but I'm sure John (Heatercathodeshort) will be able to give us some great insight as to what they were like when they were still in service!

Keep up the good work
All the best
Nick
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Old 8th Nov 2020, 2:45 pm   #5
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Default Re: Murphy V114 Saga

https://www.vintage-radio.net/forum/...d.php?t=116325

Great write up. I wonder how many of these still exist undiscovered?
This is the write up I did on my Murphy V114 some good while back with quite an amazing history but still works well. Hope it helps! MAINS EHT. Take care. Regards, John.
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Old 8th Nov 2020, 4:23 pm   #6
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Default Re: Murphy V114 Saga

Quote:
Originally Posted by 1100 man View Post
Hi Em,
Thanks for going to the trouble to do an extensive write up- makes for good reading!
That chassis looks like it's built like a tank- but then I suppose Murphy stuff usually was. I like the wiring loom all done with lacing cord. Even the symmetrical layout of the valves at the top of the chassis looks like it's been thought about!

I've never come across one of these- let alone three! What are the chances of that? At least you should have enough bits to make one good one!

I see the cabinet has that touch of Murphy weirdness with the overlapping bit at the top round the tube.

I can't comment about the electronic side of things as it's not a set I know, but I'm sure John (Heatercathodeshort) will be able to give us some great insight as to what they were like when they were still in service!

Keep up the good work
All the best
Nick

Thanks for the comment Nick. Yes this has been a very interesting experience. I don’t tend to do TVs as much these days as I prefer mainly 30s radios, but yes you’re right - this thing is and looks like a tank!

From my research from reading Johns thread about his restoration process with his V114, I learnt that it was a development of a pretty war Murphy design, there’s no EF50s in sight! I never thought I’d say this, but I actually wish there was...

I’m not too familiar with the set of valves used in this receiver, but it’s starting to become quite common for these to all be duds and unreliable.

The cabinet was the main attraction for me, the sharp corners, the construction of it is a thing of wonders, for a 9 inch set, it’s massive!!

Regards,
Ed
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Old 8th Nov 2020, 4:33 pm   #7
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Default Re: Murphy V114 Saga

Quote:
Originally Posted by Heatercathodeshort View Post
https://www.vintage-radio.net/forum/...d.php?t=116325

Great write up. I wonder how many of these still exist undiscovered?
This is the write up I did on my Murphy V114 some good while back with quite an amazing history but still works well. Hope it helps! MAINS EHT. Take care. Regards, John.
Thanks John. I referred back to your thread on your V114 extensively, it’s helped a lot with understanding the set.

It’s interesting to read how many modifications were made, stated in the service manual for it. Lets hope this project continues to go plain sailing.

Yes - I’ve had some trouble locating an appropriate EHT smoothing capacitor but believe I have now found something suitable, at least for the time being. I have my EHT probe on it constantly. Some scary stuff that!!

As for how many are out there - who knows, John? It was seen as a rarity when that the mouldy rotten one popped up a few months back, but since then, I’ve bought all 3! I thought I’d attach some photos of the cabinet of the earlier revision one, as you can see, the grill layout is completely different.

Also attached are some photos of the chassis from the first one. Sorry for the bad lighting, must’ve been the early hours of the morning, when it took them!!

Cheers,
Ed
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Old 8th Nov 2020, 4:43 pm   #8
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Default Re: Murphy V114 Saga

Hello Ed. Your probably unfortunate in having problems with the valves. Generally they are quite reliable. saying that the UU8 and the U22 tend to be self destructive but it's more they way they fail rather than frequency!

Recently I have had a few problems with Z77s, 6AM6s and a few 6F12s the Mazda versions of the Mullard EF91. The MOV Z77s being the worst culprits either going very low and in a number of cases completely lacking emission. The earlier SP41/61 are a bit clumsy in the I.F. strip. Murphy being signed up with Mazda would not have used the nice red Mullard EF50s.

The Thyratron T41s once a good pair have been sorted, are very stable. They prefer to work at 50c/s rather than 10.125k/c but seem OK in the V114. If you get ragged edges to the raster the T41 is usually responsible but may well operate in the frame OK.
Good luck with it. John.
PS the oil filled Visconol capacitors in both the line and field generators can lead you astray. Mine measured 100% both for capacity and leakage but gave low amplitude in both timebases.
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Old 8th Nov 2020, 6:43 pm   #9
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Default Re: Murphy V114 Saga

What a fantastic find! I like the styling of these, looks like it would go nicely with the Murphy SAD94L Bakelite radio sat nearby. The chassis looks very similar to the V180C that I have here. Wouldn't mind having a go at one of these myself!

Regards,
Lloyd
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Old 8th Nov 2020, 8:00 pm   #10
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Default Re: Murphy V114 Saga

Quote:
Originally Posted by Heatercathodeshort View Post
Hello Ed. Your probably unfortunate in having problems with the valves. Generally they are quite reliable. saying that the UU8 and the U22 tend to be self destructive but it's more they way they fail rather than frequency!

Recently I have had a few problems with Z77s, 6AM6s and a few 6F12s the Mazda versions of the Mullard EF91. The MOV Z77s being the worst culprits either going very low and in a number of cases completely lacking emission. The earlier SP41/61 are a bit clumsy in the I.F. strip. Murphy being signed up with Mazda would not have used the nice red Mullard EF50s.

The Thyratron T41s once a good pair have been sorted, are very stable. They prefer to work at 50c/s rather than 10.125k/c but seem OK in the V114. If you get ragged edges to the raster the T41 is usually responsible but may well operate in the frame OK.
Good luck with it. John.
PS the oil filled Visconol capacitors in both the line and field generators can lead you astray. Mine measured 100% both for capacity and leakage but gave low amplitude in both timebases.

John, I believe I had a few dud EB91s and the detector diode (can’t remember the number as of now) so I decided to change the whole lot with some matching types, these originals were Mazda numbers I believe.

Which capacitors are those John? All of the capacitors other than the postage stamp domino one was changed, which feeds the control grid of the line output valve. This read O/L on my meter and putting a capacitance tester on it gave me near to the stated value 500pf C54 I believe. Could this be the fault?
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Old 8th Nov 2020, 8:04 pm   #11
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Default Re: Murphy V114 Saga

Quote:
Originally Posted by Lloyd 1985 View Post
What a fantastic find! I like the styling of these, looks like it would go nicely with the Murphy SAD94L Bakelite radio sat nearby. The chassis looks very similar to the V180C that I have here. Wouldn't mind having a go at one of these myself!

Regards,
Lloyd
Thanks Lloyd. Very industrial look, I’m actually searching for a radio to pair it with, and a decent indoor aerial to put on top!

Regards,
Ed
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Old 8th Nov 2020, 10:51 pm   #12
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Default Re: Murphy V114 Saga

The detector diode is the little B3A based D1 called by Mazda the "TV Diode'' with a 4v heater. The Mullard version is the EA50 with a 6.3v heater. the D1 in my v114 was U/S also. The caps from memory were the .5uf in the frame discharge circuit of the T41 and a similar one but much lower value in the line. I have several manuals for the V114 with the modifications.
Mine was originally tuned to AP with a pre amplifier [still attached] but later modified to SC CH4 to give a better picture at Wellingborough Northants. John.
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Old 9th Nov 2020, 5:27 am   #13
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Default Re: Murphy V114 Saga

Quote:
Originally Posted by Heatercathodeshort View Post
The detector diode is the little B3A based D1 called by Mazda the "TV Diode'' with a 4v heater. The Mullard version is the EA50 with a 6.3v heater. the D1 in my v114 was U/S also. The caps from memory were the .5uf in the frame discharge circuit of the T41 and a similar one but much lower value in the line. I have several manuals for the V114 with the modifications.
Mine was originally tuned to AP with a pre amplifier [still attached] but later modified to SC CH4 to give a better picture at Wellingborough Northants. John.
Yes that’s right John. Yes I remember reading, I believe my example here was completely untouched, but in all fairness, I would like to have such a mod on a TV and leave it functional, as it keeps its original history!

Will update this thread once some progress occurs. Thanks again for your help.

Regards,
Ed
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Old 9th Nov 2020, 11:31 am   #14
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Default Re: Murphy V114 Saga

Really interesting story. I'm looking forward to more episodes.

Thanks,

Peter
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Old 10th Nov 2020, 11:01 am   #15
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Default Re: Murphy V114 Saga

Hello Ed

Interesting write up. Should you need it I have a spare RF unit for a V114 which was fitted to my Ch4 Viewmaster. All there and re-capped. The Viewmaster has been returned to its original Spec. (With help and advice from a good looking lad from Warnham with a couple of lorries in his back garden!)

If you need it you are very welcome to it FOC of course.

Regards Steve
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Old 10th Nov 2020, 4:45 pm   #16
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Default Re: Murphy V114 Saga

Hi.
I had a V114 a few years back. Again another that needed extensive work. At the time it wasn't a great period for me and I gave it to Ian IJK2008 Sadly I'm not in touch with him, it must be at least three years since I heard anything from him. I hope he is reading this thread as I'd like a chat.
Post 1 is brilliant.
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Old 17th Nov 2020, 5:43 am   #17
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Default Re: Murphy V114 Saga

Thanks for the kind comments and replies everyone.

Steve - Thank you for the kind offer. For now I’m trying to keep my focus on this one, but once I’ve finished with it, I’d be happy to take the spare RF/sound chassis off your hands

Murphyv310 - I’ve actually really struggled with this one. The age of the thing, and valves, plus all other suspect components really does throw you off. My original diagnosis of a tired line op valve was wrong. I lost line scan completely, it came down to an o/c line output transformer on the primary side... so looks like I’ll have to have a chat with Mike Barker, or Ed dinning! It’ll (hopefully) work just as well as it did originally. I’m at the point where I know there’s no originally left electronically, other then the wiring, I’m not ashamed of that, just means it’s needed extensive work to get it to where it’s at now - I will be tidying up the circuit though. The mix of fresh solder and the old less shiny stuff is setting off my OCD!

Peter - thanks for your kind words. Work will start again come the beginning of September, as the “spare” parts chassis is in London, I’m currently in Guilford. In the meantime, I’ll have to contemplate if I want this one rewound or if I should just remove the the one I have on the rusted chassis.

Come to think of it, I actually re soldered new PVC wires, and potted the line output transformer on the 1st chassis, so I could just nab that... will keep this thread on-going showcasing any progress made!
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Old 4th Dec 2020, 5:10 am   #18
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Default Re: Murphy V114 Saga

Hi all,

Good loptx obtained but unfortunately managed to leave the 5k contrast pot at home!

I’ll be doing the power up and test this weekend. Wish me luck all!
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Old 7th Dec 2020, 12:56 am   #19
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Default Re: Murphy V114 Saga

New LOPTx fitted and a full raster obtained. There appears to be a slight vertical lin and hoz lin issue could be addressed by adjusting the linearity controls. I’ve fitted a 3k pot plus a 2k resistor temporarily, however I’m still unable to get a form of video on the screen...

Looks as if I’m having further problems with the RF stage which I’ll now address. Will keep this thread up with my progress.
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Old 7th Dec 2020, 11:33 am   #20
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Default Re: Murphy V114 Saga

First the good news. The Mazda CRM92 looks to be in excellent condition.


What a strange effect! The raster[?] appears to be correct on the extreme left side. The first thing I would check is the frequency of the line oscillator T41 Thyratron generator.
Is the replacement LOPT from a V114? Check scan coil and the timebase panel for incorrect connections.

Replace C58 .25uf, C59 .02uf also C53 8uf, C55 .001uf, C56 .005uf, C60.02uf and C67 25uf if you have not already done so. This will eliminate all the trouble spots. The coupling capacitor C54 is probably a silver mica and should be OK. John.
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