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Murphy V280C

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PYE625
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Oh dear, I have done it again.....spotted a set on ebay and have been unable to get it from my mind. Days went by and I kept trying to tell myself it was too far away, too large and too expensive. Indeed, at £150 it was. I have to confess that temptation eventually got the better of me and I put in an offer of £75. It was refused and I forgot all about it. Until today that is. The vendor contacted me and said I could have it for £80. Well now, I could hardly say no could I ?  I mean it would be rude wouldn't it. ? 

So, in a couple of weeks I will be making an epic journey to Catford in London to collect it. A journey that may not be everyone's cup of tea, but at least a friend will be driving a vehicle suitable to transport the set in the upright position. This is because I would rather the oil in the LOPT can remained there.

Here are a few pic's for the time being, and your thoughts are most welcome.

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Topic starter Posted : 09/08/2019 11:15 pm
Till Eulenspiegel
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The Murphy V280 is an excellent TV set.  No funny valves and split heater chains, just the usual Mazda 0.3amp heater series.

But be ready to replace loads of waxie capacitors.

Another magnificently over-engineered Murphy. You won't be disappointed with it.

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Posted : 10/08/2019 12:39 am
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PYE625
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As a matter of interest, here is a link to a fascinating V280 restoration....

https://www.vintage-radio.net/forum/showthread.php?t=65554

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Topic starter Posted : 10/08/2019 12:00 pm
Lloyd
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Hi Andrew, 

I saw that set on eBay! What made me take notice of it is the fact I have a V250C, which looks almost identical, the knobs are brown on mine. I got mine from Daventry rubbish tip shortly after I passed my driving test back in 2004, I used to get Friday afternoons off work, so would head to the top to see what rubbish I could bring back! I only had a little Ford Fiesta, of 1997 vintage (it was a brilliant little car!!) I remember having to part with £20 for the set, and even got help from one of the blokes at the tip to shove it into the boot of the fiesta, which the lid wouldn’t then close on... I got it home ok, and then there was no one in to help me get it out of the car, so I sat in the car with it until my Dad got home, and he was not amused at what I’d bought! It sat at the bottom of our stairs, and I decided to try testing it, it still had its mains lead with the correct connector on it, so on went a plug and I fired it up, it came to life with a raster lacking height, and howling noises from the speaker, then went bang! Mains filter cap died loudly.. since then I’ve done nothing with it, in fact it’s still wrapped in shrink wrap and bubble wrap from when we moved. Maybe it’s going to get its turn after the Ekco A22 is finished? 

Best of luck with your set, it looks to be in lovely condition!

 Regards 

Lloyd 

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Posted : 10/08/2019 2:26 pm
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colourstar
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Looks in super condition, Andrew and blimey it's even got it's mains lead!  I know exactly what you mean about sets that once seen, seem to haunt you... Of course if we never looked at Ebay or Gumtree it would eliminate the problem but personally I don't have that much self-discipline.

I love the look of these Murphys- something about console sets that don't have doors (see also Bush T67 etc). I also seem to remember they are bloomin' heavy so make sure you have at least three Weetabix on collection day.

Steve

 

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Posted : 10/08/2019 3:26 pm
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neil1974
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It really is in lovely shape and its lucky it never ended up in a skip ? good luck with it ? .

Cheers

Neil.

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Posted : 10/08/2019 3:33 pm
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PYE625
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Thanks Guy's ? 

As a matter of fact, it nearly did end up in the skip. The lady who has it at the moment had been clearing her mother's house and the set was found stored away. She thought that the walnut cabinet was too good to throw out, so a friend of her's put the set on ebay luckily.

So, in the same family since new.... quite something for a TV set, 60 years at least.

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Topic starter Posted : 10/08/2019 4:46 pm
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Cathovisor
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I briefly had the table version of one of these: replaced all the offending caps and did some preliminary fault-finding but then just lost interest in it and moved it on.

That point marked my initial rejection of collecting television sets. "Too much chance of doing a lot of expensive work only to find out the tube or LOPT is dead". 

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Posted : 11/08/2019 8:56 am
PYE625
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Posted by: @cathovisor

 "Too much chance of doing a lot of expensive work only to find out the tube or LOPT is dead". 

Ah yes....been there once before and won't be making that mistake again !  There are ways around that problem of course, obviously a crt tester is worth its weight in gold and a ringing test can be made on the LOPT. The essential caps like the RF bypass across the mains can be removed, boost HT capacitor, line drive coupling etc can be snipped out of circuit and temporarily substituted. After ensuring all is well in the PSU section and there are no serious shorts, then first power-up tests can be made on the set.

It's all part of the joy of repairing vintage set's..... some up's and down's along the way, but I enjoy it still.

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Topic starter Posted : 11/08/2019 9:54 am
PYE625
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Today, after a seemingly daunting journey into almost the centre of London (which was not anywhere near as bad as I thought it would be), the set arrives home with me safe and sound. There were no hold-up's and I have to say it was quite a pleasent trip. Them sky-scrapers seem awfully tall to a mere country boy such as me.

The set is in really great condition and it looks like the back has never been off since the day it was installed in the house where it came from. Just a nice layer of dust inside.....

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Topic starter Posted : 24/08/2019 12:51 pm
Nuvistor
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I don’t think that set had had a lot of use, there is a thermistor that looks original but new.

 

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Posted : 24/08/2019 1:07 pm
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Cathovisor
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That looks a nice set Andrew - clearly had an easy life by the look of it.

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Posted : 24/08/2019 1:28 pm
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PYE625
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It was a simple task to extract the chassis by removal of two screws, the control knobs and sliding it out. An inspection reveals that what you say is very probably true Frank and Mike.... this set would seem to have been little used. The rubber surround of the CRT has hardened, but luckily the rubber seal of the LOPT can is nice and supple with no oil leakage. Next step is to get the hoover out and a gentle clean of the chassis will be done.

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Topic starter Posted : 24/08/2019 1:32 pm
PYE625
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The CRT is a Mazda CRM172, the valves are all Mazda and probably original and the chassis looks pretty good underneath too. Now....I wonder how many of all those wax capacitors are still serviceable? ? 

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Topic starter Posted : 24/08/2019 1:51 pm
PYE625
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Some good and not so good news.

Testing of the CRT proved ok. I re-formed the main electrolytics and thought, as there seemed no other obvious faults, it was time for some power to the set. I set the tuner for CH9, fed in a signal and applied power via a lamp limiter. The valves awoke form their slumber and the test tone was heard from the audio. Line whistle started and I eagerly awaited some kind of picture. But no, alas nothing.

HT was around 180vdc, but  the boost voltage was only 40v. Should be around 500. I snipped out the boost capacitor and substituted a new 0.1uf. This brought it up to about 275v, but still a blank screen. Probably not entirely surprising as there is only about 1.5kv of EHT.

Now, the EHT lead comes directly from the LOPT can so the EHT rectifier and the series resistor for it's heater all live inside the sealed can. Brilliant. So, where to go from here? Hmmm...

I'll take the dogs for a walk and have a think.

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Topic starter Posted : 24/08/2019 6:35 pm
Nuvistor
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Voltage doubler from the line output valve anode as a temp test before digging out the  LOPTX?

I somehow thought this was going to be your winter project. ? 

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Posted : 24/08/2019 7:28 pm
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PYE625
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It may well carry on into the winter Frank ? 

Your idea of testing with a doubler proved what I suspected with the LOPT, or at least the EHT rectifier within the same can. With a supply of EHT, we now have a raster. Albeit a rather squashed one. I hastened towards the brightness control pretty sharpish....

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Topic starter Posted : 24/08/2019 7:51 pm
Cathovisor
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From memory it's vegetable oil in the transformer can. It's just draining it off, digging out the whatever-the-Mazda-version-of-an-EY51 is and then trying to check it is going to be a PITA.

Could a transformer from your 'parts' Murphy V310 be pressed into service for testing or is it likely too different?

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Posted : 24/08/2019 7:55 pm
Terry
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The Mazda U25 has a 2V filament so a 6.3V EY51 is not a substitute.

We weren't Murphy dealers and the Murphy's with a low emission U25 that passed through my hands made me glad we weren't!

Removing the LOPT, prising open the hermetically sealed can whilst keeping the can upright, then removing the transformer and draining as much oil back in the can before changing the U25 was a pain.

Then reassembling it, carefully folding the by now crumpled and split can edge over in an attempt to fix it as securely as possible, knowing that it could never be made oil tight again, Oh why oh why couldn't Murphy have fitted the U25 outside the transformer?

Unlike changing an EY51, I can't contemplate anyone ever attempting to carry out this operation in the customer's home. Murphy dealers would have encountered this problem many, many times more often than us - did Murphy expect them to replace the complete LOPT at considerable cost to the customer or did they, perhaps, operate an exchange scheme of some sort?

And, if anybody knows of a way of recreating the perfect hermetic seal, I'd love to know what it was.

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Posted : 24/08/2019 9:26 pm
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Cathovisor
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Posted by: @terrykc

The Mazda U25 has a 2V filament so a 6.3V EY51 is not a substitute.

I didn't say it was - I was merely musing aloud about wire-ended EHT rectifiers.

Posted by: @terrykc

did Murphy expect them to replace the complete LOPT at considerable cost to the customer

I am led to believe the answer to that is "yes".

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Posted : 24/08/2019 9:43 pm
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