Bush TV22 restoration: mission impossible! - UK Vintage Radio Repair and Restoration Discussion Forum

Giulio Maiocco · 14th Feb 2009, 1:34 pm

Hello to everybody,

some time ago, I bought a TV22 with the EF91 valves used in the receiver deck, well, the restoration proved to be almost a mission impossible.

I really can't explain this, but I found the LOPT, the frame oscillator transformer and the frame output transformer with open windings, so I had a "full immersion" session rewinding these transformers.

I'm proud to show you the results after more than 3 months of hard work and I would like to assure you that rewinding the lopt (both the primary winding and the overwind, the latter corroded in a lot of spots) was not an easy task, the primary alone counts 2045 turns of 0,22mm wire and the overwind 2960 turns of 0,11mm wire.

Cheers

Giulio Maiocco (Italy)

Giulio Maiocco · 14th Feb 2009, 1:41 pm

... And this is the second part of photos. I hope you like my work!

I still have to set the width, linearity and centering controls because at the moment I don't have a standard converter, but it should arrive on monday or tuesday

Giulio

Tazman1966 · 14th Feb 2009, 2:45 pm

Hello Giulio.

It looks fantastic so far. What method did you use to rewind the transformers?

I bet you're really looking forward to your standards converter arriving.

Giulio Maiocco · 14th Feb 2009, 3:01 pm

Hello Tas,

I used a winding machine to rewind the LOPT primary, as the bobbin length was enough for the kind of winder I have, but the overwind was layer wound (37 layers of 80 turns each) completely by hand. About the frame oscillator transformer, it uses really thin wire (0,06mm + enamel) and I found that a drill with a very low rotation speed was a good method. If someone is interested, I can tell you that the winding turns ratio is quite low, in fact I wound mine with 2200 turns as the secondary winding and 2530 turns as primary, the turns ratio in my case is 1:1.15 and it seems to work well

About the standard converter, I think you won the bet, in fact I'm "anxiously" waiting Monday, always hoping this will be the right day I receive the converter!

Thank you for the positive words!

Cheers

Giulio Maiocco

af024 · 14th Feb 2009, 3:33 pm

Excellent work Giulio.

What condition did you find the laminations on the LOPT and how difficult was it to remove them (considering the windings on the inside of the paxolin tube)?

I bet you also had fun (if that's the word) winding the blocking transformer. Did you manage to do it without any wire breaks? Did the laminations go back ok?

Well done is all I can say.

Regards,

Andy

FRANK.C · 14th Feb 2009, 3:35 pm

Hi Giulio
Well done.
That was some achievement to rewind the LOPT. It obviously took a lot of dedication. How did you manage to stop the ends of the winding slipping off each layer.

Frank

Giulio Maiocco · 14th Feb 2009, 5:01 pm

Hello Andy,

well, the laminations doesn't have any trace of rust I can see, but for sure the iron core is a tight fit in the square bobbin, especially with all the wax present. A little drop of "svitol" and heat resolved the problem. About the windings, I had to rewind both, so I had nothing to loose, but if you have the primary winding in OK conditions, you might need to adopt a more delicate approach!

Also, I managed to rewind the blocking transformer without breaking the very fine wire driving it with a finger, but the first time I finished the work and attempted to solder the winding ends to the small cardboard tag, I snipped off the innermost wire. End result: start again from step1, I leave to your immagination the bad words I said...

. 2nd try I was more careful and all was OK. This rewinding job took me about 3 hours. The lamination too created no problems both to disassemble and reassemble.

Many thanks for your kind words!

Hello Frank,

rewinding the lopt required lots of time and patience, about your question, I left a bit of margin on the paper wrap (about 2mm each side) and stopped the wire with the help of a bit of scotch tape. I must confess I had a couple of "thrilling" moments when the wire tried to escape from it's place. What I can say is that the scotch tape is nowhere near melting point, as I run the whole thing for more than 1 hour and the LOPT was not even warm, even with the hot PL38 next to it!!

Cheers

Giulio

Peter.N. · 14th Feb 2009, 5:03 pm

That was a real labour of love - or fanatiscism , depending who you talk to

That chassis looks brilliant, I remember those sets when they were new - and that's what they looked like.

Steve_P · 14th Feb 2009, 9:40 pm

Love, Peter. And also sheer brilliance too. Well done old bean.

Of course if you're into rewinding line output transformers, I'm sure there will be plenty takers....

Cheers,

Steve P.

Hunts smoothing bomb · 15th Feb 2009, 11:12 am

Hi Giulio,

Absolutely outstanding work!

The re-wound LOPT looks excellent, Well done

I'll post you the LOPT from my TV22 to rewind too!!

All the best and can't wait to see a picture on the set when you have your Aurora.

Cheers
Lee

Boom · 15th Feb 2009, 3:57 pm

I've had my TV22 sitting in the front room for 20 years waiting to be restored. After seeing Giulios w*rk and another forum members TV22 running with a terrific picture on it yesterday I have finally been given the incentive to go ahead.

af024 · 15th Feb 2009, 9:19 pm

Hello Giulio,

Yes I can indeed imagine the naughty words. I'm amazed at your persistance.

I'm also interested to learn that the LOPT runs cool. Maybe running it without pitch is a good move.

This work should certainly provide us all with inspiration.

Cheers,

Andy

Giulio Maiocco · 16th Feb 2009, 10:52 am

Hello guys (and gals)

The Aurora converter arrived this morning, so I set all the various controls and... we have beautiful video!! Please note that I'm not too good as a photographer, in reality the image on the screen is much better and razor-sharp focussed!

Lee, what's exactly the problem with your LOPT? I may help you

Also, peter and Steve, thank you for your kind words, I think I'm quite young (near 26 years old), but that was a great experience and I learned lots of things, even if I already restored quite a bit of vintage TV sets! I'm always of the idea that a work must be done the best way possible or nothing

Andy, yes, the LOPT does indeed run cooler without the pitch, but if you eliminate it, you must varnish the overwind with some anti-corona dope to avoid flashes. If you don't follow this "rule" it's more than probable (I would say sure and guaranteed) that the insulations in the overwind will breakdown

Cheers

Giulio

Sideband · 16th Feb 2009, 9:34 pm

Giulio, that is fantastic work!

You also have a very good CRT. I hope it gives many years of good service.

Rich.

af024 · 16th Feb 2009, 10:08 pm

A cracking result Giulio.

I bet that set won't ever leave your collection - there's far too much of your blood, sweat and tears there!

Excellent stuff.

Andy

Tazman1966 · 16th Feb 2009, 10:23 pm

Well Giulio, I don't know what to say! What a pleasing result. I hope that you enjoy the set for years to come.

FRANK.C · 16th Feb 2009, 10:25 pm

Mighty work, a great outcome.

One you should be really proud of.

Frank

chipp1968 · 16th Feb 2009, 10:46 pm

Very impressive ,lovelly little set

Line whistle · 16th Feb 2009, 10:49 pm

Top job,
Cheers, Des.

Top Anode · 17th Feb 2009, 7:38 am

More patience than I had at your age! Well done.

As a child, I was fascinated by the heart shaped cam on my mother's sewing machine. It guided the cotton onto the bobbin for re-winding. I can imagine that such a form would be difficult to design, so are there proprietary ones for coil-winding etc.? It occurs to me that such a shape would only have to be scaled up or down to do most straight winding jobs, but the more complex winding on IF transformers and tuning coils is quite a different issue.

I've often wondered what voltages the lacquer coating will withstand. On a LOPT, I would imagine there about as high as one would get in the domestic environment. No doubt the original designers work hard to give some leeway in the design, but does anyone know the typical voltages between strands?

It does sound as though the original wire might have been faulty.

14th Feb 2009, 1:34 pm	#1
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Bush TV22 restoration: mission impossible! Hello to everybody, some time ago, I bought a TV22 with the EF91 valves used in the receiver deck, well, the restoration proved to be almost a mission impossible. I really can't explain this, but I found the LOPT, the frame oscillator transformer and the frame output transformer with open windings, so I had a "full immersion" session rewinding these transformers. I'm proud to show you the results after more than 3 months of hard work and I would like to assure you that rewinding the lopt (both the primary winding and the overwind, the latter corroded in a lot of spots) was not an easy task, the primary alone counts 2045 turns of 0,22mm wire and the overwind 2960 turns of 0,11mm wire. Cheers Giulio Maiocco (Italy) Attached Thumbnails

14th Feb 2009, 1:41 pm	#2
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Bush TV22 restoration: mission impossible! ... And this is the second part of photos. I hope you like my work! I still have to set the width, linearity and centering controls because at the moment I don't have a standard converter, but it should arrive on monday or tuesday Giulio Attached Thumbnails

14th Feb 2009, 2:45 pm	#3
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Bush TV22 restoration: mission impossible! Hello Giulio. It looks fantastic so far. What method did you use to rewind the transformers? I bet you're really looking forward to your standards converter arriving. __________________ All the very best, Tas

14th Feb 2009, 3:01 pm	#4
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Bush TV22 restoration: mission impossible! Hello Tas, I used a winding machine to rewind the LOPT primary, as the bobbin length was enough for the kind of winder I have, but the overwind was layer wound (37 layers of 80 turns each) completely by hand. About the frame oscillator transformer, it uses really thin wire (0,06mm + enamel) and I found that a drill with a very low rotation speed was a good method. If someone is interested, I can tell you that the winding turns ratio is quite low, in fact I wound mine with 2200 turns as the secondary winding and 2530 turns as primary, the turns ratio in my case is 1:1.15 and it seems to work well About the standard converter, I think you won the bet, in fact I'm "anxiously" waiting Monday, always hoping this will be the right day I receive the converter! Thank you for the positive words! Cheers Giulio Maiocco

14th Feb 2009, 3:33 pm	#5
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: Bush TV22 restoration: mission impossible! Excellent work Giulio. What condition did you find the laminations on the LOPT and how difficult was it to remove them (considering the windings on the inside of the paxolin tube)? I bet you also had fun (if that's the word) winding the blocking transformer. Did you manage to do it without any wire breaks? Did the laminations go back ok? Well done is all I can say. Regards, Andy __________________ Now where on earth did I remove that from?

14th Feb 2009, 3:35 pm	#6
FRANK.C Heptode Join Date: Feb 2006 Location: Roscommon, Ireland Posts: 732	Re: Bush TV22 restoration: mission impossible! Hi Giulio Well done. That was some achievement to rewind the LOPT. It obviously took a lot of dedication. How did you manage to stop the ends of the winding slipping off each layer. Frank

14th Feb 2009, 5:01 pm	#7
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Bush TV22 restoration: mission impossible! Hello Andy, well, the laminations doesn't have any trace of rust I can see, but for sure the iron core is a tight fit in the square bobbin, especially with all the wax present. A little drop of "svitol" and heat resolved the problem. About the windings, I had to rewind both, so I had nothing to loose, but if you have the primary winding in OK conditions, you might need to adopt a more delicate approach! Also, I managed to rewind the blocking transformer without breaking the very fine wire driving it with a finger, but the first time I finished the work and attempted to solder the winding ends to the small cardboard tag, I snipped off the innermost wire. End result: start again from step1, I leave to your immagination the bad words I said.... 2nd try I was more careful and all was OK. This rewinding job took me about 3 hours. The lamination too created no problems both to disassemble and reassemble. Many thanks for your kind words! Hello Frank, rewinding the lopt required lots of time and patience, about your question, I left a bit of margin on the paper wrap (about 2mm each side) and stopped the wire with the help of a bit of scotch tape. I must confess I had a couple of "thrilling" moments when the wire tried to escape from it's place. What I can say is that the scotch tape is nowhere near melting point, as I run the whole thing for more than 1 hour and the LOPT was not even warm, even with the hot PL38 next to it!! Cheers Giulio

14th Feb 2009, 5:03 pm	#8
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Bush TV22 restoration: mission impossible! That was a real labour of love - or fanatiscism , depending who you talk to That chassis looks brilliant, I remember those sets when they were new - and that's what they looked like.

14th Feb 2009, 9:40 pm	#9
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush TV22 restoration: mission impossible! Love, Peter. And also sheer brilliance too. Well done old bean. Of course if you're into rewinding line output transformers, I'm sure there will be plenty takers.... Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

15th Feb 2009, 11:12 am	#10
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: Bush TV22 restoration: mission impossible! Hi Giulio, Absolutely outstanding work! The re-wound LOPT looks excellent, Well done I'll post you the LOPT from my TV22 to rewind too!! All the best and can't wait to see a picture on the set when you have your Aurora. Cheers Lee __________________ Lee

15th Feb 2009, 3:57 pm	#11
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: Bush TV22 restoration: mission impossible! I've had my TV22 sitting in the front room for 20 years waiting to be restored. After seeing Giulios w*rk and another forum members TV22 running with a terrific picture on it yesterday I have finally been given the incentive to go ahead.

15th Feb 2009, 9:19 pm	#12
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: Bush TV22 restoration: mission impossible! Hello Giulio, Yes I can indeed imagine the naughty words. I'm amazed at your persistance. I'm also interested to learn that the LOPT runs cool. Maybe running it without pitch is a good move. This work should certainly provide us all with inspiration. Cheers, Andy __________________ Now where on earth did I remove that from?

16th Feb 2009, 10:52 am	#13
Giulio Maiocco Tetrode Join Date: Jan 2006 Location: Fossano (CN) Italy Posts: 71	Re: Bush TV22 restoration: mission impossible! Hello guys (and gals) The Aurora converter arrived this morning, so I set all the various controls and... we have beautiful video!! Please note that I'm not too good as a photographer, in reality the image on the screen is much better and razor-sharp focussed! Lee, what's exactly the problem with your LOPT? I may help you Also, peter and Steve, thank you for your kind words, I think I'm quite young (near 26 years old), but that was a great experience and I learned lots of things, even if I already restored quite a bit of vintage TV sets! I'm always of the idea that a work must be done the best way possible or nothing Andy, yes, the LOPT does indeed run cooler without the pitch, but if you eliminate it, you must varnish the overwind with some anti-corona dope to avoid flashes. If you don't follow this "rule" it's more than probable (I would say sure and guaranteed) that the insulations in the overwind will breakdown Cheers Giulio Attached Thumbnails

16th Feb 2009, 9:34 pm	#14
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,571	Re: Bush TV22 restoration: mission impossible! Giulio, that is fantastic work! You also have a very good CRT. I hope it gives many years of good service. Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

16th Feb 2009, 10:08 pm	#15
af024 Octode Join Date: Jan 2003 Location: Ashby-de-la-Zouch (it's not by the sea) Posts: 1,255	Re: Bush TV22 restoration: mission impossible! A cracking result Giulio. I bet that set won't ever leave your collection - there's far too much of your blood, sweat and tears there! Excellent stuff. Andy __________________ Now where on earth did I remove that from?

16th Feb 2009, 10:23 pm	#16
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Bush TV22 restoration: mission impossible! Well Giulio, I don't know what to say! What a pleasing result. I hope that you enjoy the set for years to come. __________________ All the very best, Tas

16th Feb 2009, 10:25 pm	#17
FRANK.C Heptode Join Date: Feb 2006 Location: Roscommon, Ireland Posts: 732	Re: Bush TV22 restoration: mission impossible! Mighty work, a great outcome. One you should be really proud of. Frank

16th Feb 2009, 10:46 pm	#18
chipp1968 Rest in Peace Join Date: Jul 2006 Location: Somerset, UK. Posts: 2,356	Re: Bush TV22 restoration: mission impossible! Very impressive ,lovelly little set

16th Feb 2009, 10:49 pm	#19
Line whistle Hexode Join Date: Jun 2006 Location: Bedfordshire, UK. Posts: 341	Re: Bush TV22 restoration: mission impossible! Top job, Cheers, Des. __________________ www.freewebs.com/405tv

17th Feb 2009, 7:38 am	#20
Top Anode Tetrode Join Date: Dec 2008 Location: Walton on the Naze Essex Uk Posts: 91	Re: Bush TV22 restoration: mission impossible! More patience than I had at your age! Well done. As a child, I was fascinated by the heart shaped cam on my mother's sewing machine. It guided the cotton onto the bobbin for re-winding. I can imagine that such a form would be difficult to design, so are there proprietary ones for coil-winding etc.? It occurs to me that such a shape would only have to be scaled up or down to do most straight winding jobs, but the more complex winding on IF transformers and tuning coils is quite a different issue. I've often wondered what voltages the lacquer coating will withstand. On a LOPT, I would imagine there about as high as one would get in the domestic environment. No doubt the original designers work hard to give some leeway in the design, but does anyone know the typical voltages between strands? It does sound as though the original wire might have been faulty.