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-   -   Pye v4 (https://www.vintage-radio.net/forum/showthread.php?t=53536)

oldticktock 29th Apr 2010 1:56 pm

Pye v4
 
5 Attachment(s)
Some pics of the next patient, I guess this dates from 1953?

Looks like it was set of Alexander Palace, before it travelled up north

I will have to fashion a new focus lever as the orginal is gone, or just leave it off not sure yet. Perhaps the oaf broke that at the same time as the neck

oldticktock 29th Apr 2010 1:58 pm

Re: Pye v4
 
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A few more, always wondered what the inside of a tube looked like when the neck gets broken, does it go with a bang or a wimper?

I guess by the manufacture date and with just the one aerial socket this must have been a band 1 only

I will be working from Trader 1120/T47

ppppenguin 29th Apr 2010 2:07 pm

Re: Pye v4
 
When you break the neck of a CRT there's normally just a brief hiss of air and a little tinkle of glass. Along with a slightly strange smell. You would be very unlucky to get an implosion or any significant flying glass by breaking the neck.

The V4 and VT4 look very similar except the VT4 had a 13 channel tuner. Same difference as between the V2 and VT2 which are the bakelite cased equivalents. The VT2 was the first 13 channel set because Pye jumped the gun in 1954. Not sure if the VT4 was introduced at the same time.

PS: Jon's pages give the dates: http://www.thevalvepage.com/tvmanu/pye/body_pye.htm

oldticktock 29th Apr 2010 2:10 pm

Re: Pye v4
 
Is the strange smell from the CRT or the person who did the breaking ;D.

joking aside, what should i do with the old one I was thinking of glueing it back and having it as a display piece, if not how should i dispose of it? I guess not the bottle bank ;)

ppppenguin 29th Apr 2010 2:15 pm

Re: Pye v4
 
Display it if you want. Otherwise wrap it well and stick it in the bin. Perhaps not advisable if your council uses plastic bags but fine for a wheelie bin.

FRANK.C 29th Apr 2010 2:26 pm

Re: Pye v4
 
There is probably enough neck left for it to be regunned in the future. Is it worth saving?

Frank

FERNSEH 29th Apr 2010 5:25 pm

Re: Pye v4
 
Quote:

Originally Posted by FRANK.C (Post 325887)
There is probably enough neck left for it to be regunned in the future. Is it worth saving?

It might be worth considering keeping the broken tube because these 14" rectangular tubes are becoming very rare. The CRT could be rescreened and regunned by RACS in France. Although one would only install a rebuilt 14" tube into a very special TV set. The CRT rebuild cost is in the region of 500 Euros.

DFWB.

oldticktock 29th Apr 2010 6:40 pm

Re: Pye v4
 
5 Attachment(s)
The chassis out. Thanks to FERNSEH, I have a CRT to test with.

I will box up the old broken one and save it then, you never know.

Oh! lots of those waxies, the main smoothing can looks in good condition. and LOPT looks to be in good condition, no nasty cracks or fungy.

Mutters to himself, "must not look at the whole mountain just concentrate on the next step"

Heatercathodeshort 29th Apr 2010 6:46 pm

Re: Pye v4
 
Just a word of warning here. This is an early version of the V4 using the pink perspex implosion screen. The original scanning coils had the line and frame coils insulated from each other by celophane sheets, the sort sweets are wrapped in. After a period this becomes brittle with heat and turns to powder resulting in a large breakdown between the two sets of coils.This was often confused with LOPT failure and customers were very reluctant to pay further bills after tube replacement.
This usually occured when the CRT was replaced due to the disturbance of the coils themselves. Later versions and all replacement coils were insulated with polythene and remained supple and a good insulator. If you have the celophane coils there is a risk of failure and they cannot be repaired. I have two V4's with this fault!
These are great sets and give a really good black and white picture but like all complicated things in life tend to be frustrating and difficult to fault trace if you are not familiar with 'Automatic Picture Control' [Vision AGC] and line flywheel sync.
Hope you manage to sort it. Regards, John.

oldticktock 29th Apr 2010 6:51 pm

Re: Pye v4
 
Oh great, FERNSEH warned me too, you know the more I learn about this set the more I begin to wish I had never seen it. I have to remove the scan coils to replace the crt so its a no win situation. Anyone need some V4 spares?

I'm not sure i'm going to go ahead with this. I don't need the pain this is going to generate I'd rather take it on the chin put it down to poor choice and impulse buying and find something more suitable.

Chris

oldticktock 29th Apr 2010 7:22 pm

Re: Pye v4
 
3 Attachment(s)
Well thought I had nothing to loose and decided to remove the scan coil unit and for once some luck!

The insulation between coils is the polythene, so despite being an early model, perhaps this had a replacement at some point thankfully for me :clap:

Chris

p.s added a picture of where the neck should have been

Sideband 29th Apr 2010 7:49 pm

Re: Pye v4
 
Ahh you read my mind before I could post! I was going to suggest looking at the coils first as you would have to remove them anyway. You could then make a decision. As it happens, you seem to have the later coils so there will be a picture on this tonight then?;D.

Not sure about the regun possibility. I think it depends on where the neck is broken and it seems as if the whole neck is broken off. There are also small cracks in the bulb where the neck was. That used to be the case anyway when I took tubes back to the local regunners and they would always have to recoat the screen if the neck had been broken even if the phosphor appeared to be intact.

Might be worth contacting RACS to see what they say.


Rich.

oldticktock 29th Apr 2010 7:57 pm

Re: Pye v4
 
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Hi Richard,

A picture tonight ;D hopefully I will pickup the replacement from FERNSEH's shop tomorrow (looking forward to seeing that) who knows maybe a picture tomorrow;)

I did wonder about the tube after removing the scan coils and seeing the extent and position of the break. Maybe I will glue and have a display piece or maybe fill it with earth and grow some exotic plant would make a talking piece. At 500 Euros if it could be repaired, I cannot envisage a TV that would warrant such expense on just one component then again what do I know.

Attached are two photos of the scan coil outer assembly.

The end of the assembly rotates in and out, on the side are two curved tags which can be rotated and finally there is a thumbscrew device which seems to rotate the coils and can be locked. Is this all to do with picture centering?

Just had a look at the valves, they look original the PL81 is a Marconi and is odd shaped, I've only seen the Mullard PL81 before

Similar valve line up to the bush's except 3 ECC82's (no ECC83 in here) the addition of ECL80's, a whole raft of EF80's and the tiny litte EY51 20 valves in total.

Chris

Heatercathodeshort 29th Apr 2010 8:31 pm

Re: Pye v4
 
Great news! Those are mk2 coils that must have been replaced in the past. Worth having a go now as you can't damage these! J.

murphyv310 29th Apr 2010 8:47 pm

Re: Pye v4
 
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Hi OTT.
As the other guys have said the line scan coils can be a problem on these sets, made worse by damp conditions I may add. The surface rust worried me bit as the one here suffered with the same complaint and not only was the scan coils duff but the LOPT was suffering with saturation problems although that can be sorted out. Perhaps others would disagree but the replacement scan coils I got for mine were left soaking in WD40 for a few weeks and have been OK since fitting over a year ago!
Here's mine in the flesh!

oldticktock 29th Apr 2010 10:21 pm

Re: Pye v4
 
2 Attachment(s)
Hi I'm a bit confused

When I removed the EHT lead from the side of the PYE's CRT I was surprised it was like an anode cap. Why? because the two CRTs I have come into contact with on the Bush TV62 & 63 had a claw like connector which inserted into a recess in the CRT.

The Bush TV62 was a MW36-24 (this is supposed to be the same CRT in the PYE V4)
The Bush TV63 was an AW36-20

I found a label in the bottom of the cabinet of the PYE and it states MW36-44! this is in contradiction of the trader sheet which states MW36-24. Is this why the EHT cap differs? do the MW36-24's have the claw connector and recess where the MW36-44 have the anode type connector and cap lead.

I'm worried that the CRT FERNSEH is now the wrong type and I have wasted his time

Chris

FERNSEH 29th Apr 2010 10:54 pm

Re: Pye v4
 
3 Attachment(s)
Hi Cris,
The Mullard MW36-44 employs a pentode gun assembly whereas the MW36-24 has a tetrode gun. The tubes are interchangable, the only difference is that pin 11 (anode2) of the MW36-44 can be connected to the cathode or ground to provide a degree of pre-focusing.

The MW36-24 was fitted into many Pye V4 sets.

DFWB.

oldticktock 29th Apr 2010 11:03 pm

Re: Pye v4
 
Thanks David for clearing that up, I hope one day to own one of your CRT stools :)

chipp1968 29th Apr 2010 11:07 pm

Re: Pye v4
 
I had one of these sets back in the 80s . had it for years then got rid just a few years ago before a few less years ago getting into 405line tvs ..typical
Mine was dated 1954 , but was single channel .It had fretted metal blanking plate covering the ITV "ready" hole:D

oldticktock 30th Apr 2010 1:49 pm

Re: Pye v4
 
2 Attachment(s)
Hi, arrived back safely with the replacement CRT a locally produced one at that, from Teletronic, Monkwearmouth, Sunderland works.

David, thank you very much for your warm and friendly welcome and the tour around your shop, you don't know what a pleasure that was for me, being the first time up close to so many vintage TV's was such a treat.

I have removed the ION trap from the broken neck of the old tube and attached to the new CRT as you advised, aligned with pin3 and arrow pointing towards the screen.

Now I will set about removing the old screen end fit this new one, reseat the scan coils, snip C110 and give it a tickle and see what fails to happen :)

Chris


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