Another PYE LV20

Hi Ian,

I know first hand how upsetting this can be having it happen to me on my PYE V4. Some people have a strange idea about packing. More upsetting is to think the poor set survived all these years only to be broken before reaching its new home, where it would be lavished with all the love and attention it deserves.

Still the phoenix will arise and I'm sure you will find another tube, a shame though that a rare tube is taken out of the pool.

My LV20 had London stamped in red on the underside of the chassis, below where the CRT would be.

Interestingly it looks like yours is fitted with a MW22-16 with B12 base and Ion Trap, mine is fitted with the MW22-14 with B9G base without IT. I wonder if yours was original or a replacement?

Chris

Chris / Trevor

Thanks for your kind remarks. Here are a few more shots as it is (in the attic!). The tube was an MW22-16. As you can see several components have been changed over the years so maybe the tube was as well. It looks like I have history to unravel when I start i.e. careful check of all the "new" work).

Ian

Click to see full size image

Click to see full size image

Click to see full size image

Hi Ian
It took some belt to do that to the tube. Was the tube loose in it's rim band?  It is gutting when something like this happens.
Good luck with the quest for a tube, I am sure one will turn up.

Frank

Hi

The TV is a London set so therefore an LV20. I checked and it is stamped underneath where indicated by Chris.

I put a CRM93 in it tonight and it fits physically however I don't like the look of the tube. It has developed a patch on the phosphor and I wonder if it has gone to air. I am not even sure if it will work OK in the set even if it was good. I think I might take it down to let Trevor run the rule over it.

So all progress halted just now I am afraid.

Ian

Hi Ian,

I know the feeling only too well!
Being this far north I usually have to get stuff posted/couriered up here.
On several occasions I have had stuff wrecked - all Bakelite.
The worst was a 1936 'Dougal' Ekco bakelite radio which arrived in several bits despite being very well packed. Fortunately the seller took it back.
I subsequently managed to get a replacement which I was able to collect when i was down in England.
So good luck with the restoration. I hope you manage to pick up a good replacement tube.

Andy

Trevor tested the tube and it is knackered.

But - it looks like I have found an exact reaplacement which I just need to get from Essex to Glasgow in one piece. So maybe the Pye will live yet.

Ian

The tube is here! And its in one piece.

I need to get a B8G base as the set has a 12 pin base for the MW22-16. I am tempted to 'jury rig' some connections to see if it will work (is this wise?)

Ian

No heater continuity - looks like I am stuffed.....

Hi Ian,

I'm also after a B8G base if you come across a source let me know.

Regarding jury rigging, It will be fine and at least you can get some indication of the state of play with the CRT.  I used croc clip-ins when I was testing my LV20 , you can see the mass of flying leads to the CRT in my thread, just be careful not to short between pins.

Good luck

Chris

Hi Chris

Check the PS to my last post - it's not good news.

Never mind I've got a blocked drain to go and play with. Joy!

Ian

Oh that's cruel!!

have you tried cleaning the pins just in case?

If it really is O/C you could always try welding with EHT from another set  😯 I've read of others doing it and it sometimes works.

Chris

Trevor

Flashing EHT, now that's an invite that can't be resisted!

I'll get back to you and we can work out a weekend that suits.

A bit of luck now would be nice with this one.

Ian

Now Ian you should take video camera and upload that to youtube, its not often we get to see this performed and it would be interesting to watch. I've never seen it done I wonder how many TV bods on here have.

Chris

i have seen it done a few times use an isolated probe from the top cap of the line output valve. earth one side of the heater and bring probe to other heater pin you will get an arc  no need to touch the pin switch off and check the heater, be aware you may create a heater cathode short
good luck
rob t

Hi Rob,

If you do create a HKS could you not the use a dedicated heater TX to supply the correct heater voltage?

Chris

cant see why not, it never happend to the ones i witnessed but was told it could happen
rob t

Would certainly be interesting to watch. I love watching anything that arcs.

Frank

Hi

No time to see Trevor so far but the LV20 now has a tube which hopefully is OK.

Would love to put some power on so I will try to get on with it. I am a bit hampered though as we have builders putting up a new kitchen extension on the back of the house. The trade off is I get a shed to myself so hopefully I won't have to work on the kitchen table much longer.

Chris - any chance we could change the title of this thread as the set is most definately an LV20 not a BV20 (my error).

Ian

Power applied tonight after I found the cause of a high resistance reading across the mains (bad heater connection on an EB41 valve which of course was last in the chain).

Really good strong line whistle, no smoke or distress but nothing on screen.

I had to stop but will follow up with some dc checks on the HT and the CRT connections.

It is good to move forward at last!

Ian

Nothing doing on screen so far. HT volts on the A1 anode are 218V (about 20V low) the cathode seems OK at 35+ Volts but the grid is only going down to -4.5 volts (should be -30V).

The CRT heaters only at 4.2V so problem in the chain. Chris had the same thing on his caused by a Hunts decoupler. I will change these and see where we are then.

Ian