Bush TV 22 no line output voltage - UK Vintage Radio Repair and Restoration Discussion Forum

howards · 17th May 2017, 12:45 pm

I now have my father's Bush TV22, it was bought new in 1953 and only used for a few hours a night for around 12 months when he was diagnosed with TB, my mother put the set into storage in the attic where it has remained for the last 63 years and it is in pristine condition, all valves are lit including the tube, tuner and amplifier appear to be working OK, but no EHT to the side of the tube, can any one help as I would really like to be able to use this with a video or something else, if this was a valve amplifier I would be able to fix the problem but never worked on valve TV. Howard.

slidertogrid · 17th May 2017, 12:52 pm

Hi You will need a standards converter to operate this set as it is 405 line.
The most probable cause of your problem is leaky or shorted wax capacitors.
They will all need changing for reliable results. There are a couple that are easily missed behind the tag board if I remember correctly.
Regards
Rich.

Dickie · 17th May 2017, 12:58 pm

Also any hint of damp in the LOPT will upset EHT generation. There's plenty of advice on the forum about how to dry it out.

Lloyd 1985 · 17th May 2017, 4:45 pm

If there is no EHT, take a look at the EHT rectifier valve, it's tacked on the side of the line output transformer, make sure it's connections are good, and see if you can see the heater lighting in the valve. The heater for this valve is powered by the winding on the top of the transformer, check this for continuity, which will only be a few ohms. If the line output stage isn't running well (because of leaky caps or damp transformer, as mentioned above) then there may not be enough power to heat the EHT rectifier, which will stop any EHT reaching the tube.

Regards,
Lloyd.

Voxophone · 17th May 2017, 5:05 pm

How have you determined that there is definately no EHT? Can you hear a line whistle?

howards · 17th May 2017, 8:45 pm

Silent no whistle, also rectifier valve on side of line output transformer is not lighting up, Howard.

Rik1967 · 18th May 2017, 12:06 pm

Hi there, I am in the middle of restoring my TV22, I have had 2 transformers re wound,
(line osc etc) and replaced almost all capacitors, as 90% were dud
It wasn't a difficult job, and also found lots of resistors faulty. I would advise you change the caps one by one.
If the line output tramsformer has gone, it can be re wound, but I think you should replace the caps as the previous replies suggest. No line could be one , of many faults.
PM me if you get stuck as Im on the same learning curve!! Lots of info about this set available.
Good Luck Richard.

howards · 18th May 2017, 3:02 pm

Thanks to every one for the info, Regards Howard.

Voxophone · 18th May 2017, 4:06 pm

If you're going to replace the wax caps in stages with power-ups in between, it would be a good idea to prioritise the four or so caps connected across the heater chain. If any of these fails short-circuit it could stress or burn out a few valve filaments.

The grid coupling cap to the line output valve should also be prioritised for the sake of the LOPT.

This is the advice I was given when restoring my TV22.

Edit - Which model TV22 is yours by the way? The service information differs between the Mk 1 and Mk 2, and the latter also had a couple of subtypes. I think the Mk 2 may have been introduced sometime in 1953 so yours could possibly be either.

Liam

howards · 18th May 2017, 10:02 pm

How can i tell if it is a mk1 or 2 ?, Howard.

Lloyd 1985 · 18th May 2017, 11:26 pm

If I remember right, the Mk 1 has EF91 valves on the RF deck, and the Mk 2 has EF80's. Also the CRT, in the Mk 1 it will be a Mullard MW22-18, and the Mk 2 will be a Mullard MW22-16 with ion trap magnet.

Just to add to this, there was also a model TV22 A, which is completely different to the above! If it's a TV22 A it will say on the back.

Best way is to take a picture of the inside and post it here, one of us will be able to identify it.

Regards,
Lloyd.

Voxophone · 19th May 2017, 4:50 pm

This page has a lot of information on line output and EHT problems which may be useful: http://www.oldtellys.co.uk/otltbeht.html

Liam

Ian - G4JQT · 19th May 2017, 5:29 pm

Here is some data I collated for the TV22/24 Mk I and II. It states Mk II in the document, but the LOPT electrical characteristics for Mk I and Mk II models are the same. However as already stated, I can confirm that the TV22A/TV24A have completely different LOPTs.

Hope someone finds the info useful.

Ian

howards · 19th May 2017, 9:56 pm

Thanks for that info, it is a MK2, Howard.

17th May 2017, 12:45 pm	#1
howards Retired Dormant Member Join Date: Dec 2008 Location: Whiston, Merseyside, UK. Posts: 41	Bush TV 22 no line output voltage I now have my father's Bush TV22, it was bought new in 1953 and only used for a few hours a night for around 12 months when he was diagnosed with TB, my mother put the set into storage in the attic where it has remained for the last 63 years and it is in pristine condition, all valves are lit including the tube, tuner and amplifier appear to be working OK, but no EHT to the side of the tube, can any one help as I would really like to be able to use this with a video or something else, if this was a valve amplifier I would be able to fix the problem but never worked on valve TV. Howard.

17th May 2017, 12:52 pm	#2
slidertogrid Octode Join Date: Apr 2005 Location: Peterborough, Cambridgeshire, UK. Posts: 1,898	Re: Bush TV 22 no line output voltage Hi You will need a standards converter to operate this set as it is 405 line. The most probable cause of your problem is leaky or shorted wax capacitors. They will all need changing for reliable results. There are a couple that are easily missed behind the tag board if I remember correctly. Regards Rich. __________________ The rotation of the earth really makes my day...

17th May 2017, 12:58 pm	#3
Dickie Octode Join Date: Sep 2004 Location: St. Albans, Hertfordshire, UK. Posts: 1,478	Re: Bush TV 22 no line output voltage Also any hint of damp in the LOPT will upset EHT generation. There's plenty of advice on the forum about how to dry it out. __________________ Regards, Richard, BVWS member

17th May 2017, 4:45 pm	#4
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,819	Re: Bush TV 22 no line output voltage If there is no EHT, take a look at the EHT rectifier valve, it's tacked on the side of the line output transformer, make sure it's connections are good, and see if you can see the heater lighting in the valve. The heater for this valve is powered by the winding on the top of the transformer, check this for continuity, which will only be a few ohms. If the line output stage isn't running well (because of leaky caps or damp transformer, as mentioned above) then there may not be enough power to heat the EHT rectifier, which will stop any EHT reaching the tube. Regards, Lloyd.

17th May 2017, 5:05 pm	#5
Voxophone Hexode Join Date: Oct 2015 Location: Sunderland, Tyne and Wear, UK. Posts: 340	Re: Bush TV 22 no line output voltage How have you determined that there is definately no EHT? Can you hear a line whistle?

17th May 2017, 8:45 pm	#6
howards Retired Dormant Member Join Date: Dec 2008 Location: Whiston, Merseyside, UK. Posts: 41	Re: Bush TV 22 no line output voltage Silent no whistle, also rectifier valve on side of line output transformer is not lighting up, Howard.

18th May 2017, 12:06 pm	#7
Rik1967 Triode Join Date: Nov 2016 Location: Isle of Wight, UK. Posts: 39	Re: Bush TV 22 no line output voltage Hi there, I am in the middle of restoring my TV22, I have had 2 transformers re wound, (line osc etc) and replaced almost all capacitors, as 90% were dud It wasn't a difficult job, and also found lots of resistors faulty. I would advise you change the caps one by one. If the line output tramsformer has gone, it can be re wound, but I think you should replace the caps as the previous replies suggest. No line could be one , of many faults. PM me if you get stuck as Im on the same learning curve!! Lots of info about this set available. Good Luck Richard.

18th May 2017, 3:02 pm	#8
howards Retired Dormant Member Join Date: Dec 2008 Location: Whiston, Merseyside, UK. Posts: 41	Re: Bush TV 22 no line output voltage Thanks to every one for the info, Regards Howard.

18th May 2017, 4:06 pm	#9
Voxophone Hexode Join Date: Oct 2015 Location: Sunderland, Tyne and Wear, UK. Posts: 340	Re: Bush TV 22 no line output voltage If you're going to replace the wax caps in stages with power-ups in between, it would be a good idea to prioritise the four or so caps connected across the heater chain. If any of these fails short-circuit it could stress or burn out a few valve filaments. The grid coupling cap to the line output valve should also be prioritised for the sake of the LOPT. This is the advice I was given when restoring my TV22. Edit - Which model TV22 is yours by the way? The service information differs between the Mk 1 and Mk 2, and the latter also had a couple of subtypes. I think the Mk 2 may have been introduced sometime in 1953 so yours could possibly be either. Liam Last edited by Voxophone; 18th May 2017 at 4:17 pm.

18th May 2017, 10:02 pm	#10
howards Retired Dormant Member Join Date: Dec 2008 Location: Whiston, Merseyside, UK. Posts: 41	Re: Bush TV 22 no line output voltage How can i tell if it is a mk1 or 2 ?, Howard.

18th May 2017, 11:26 pm	#11
Lloyd 1985 Nonode Join Date: Jun 2008 Location: Coningsby, Lincolnshire, UK. Posts: 2,819	Re: Bush TV 22 no line output voltage If I remember right, the Mk 1 has EF91 valves on the RF deck, and the Mk 2 has EF80's. Also the CRT, in the Mk 1 it will be a Mullard MW22-18, and the Mk 2 will be a Mullard MW22-16 with ion trap magnet. Just to add to this, there was also a model TV22 A, which is completely different to the above! If it's a TV22 A it will say on the back. Best way is to take a picture of the inside and post it here, one of us will be able to identify it. Regards, Lloyd.

19th May 2017, 4:50 pm	#12
Voxophone Hexode Join Date: Oct 2015 Location: Sunderland, Tyne and Wear, UK. Posts: 340	Re: Bush TV 22 no line output voltage This page has a lot of information on line output and EHT problems which may be useful: http://www.oldtellys.co.uk/otltbeht.html Liam

19th May 2017, 9:56 pm	#14
howards Retired Dormant Member Join Date: Dec 2008 Location: Whiston, Merseyside, UK. Posts: 41	Re: Bush TV 22 no line output voltage Thanks for that info, it is a MK2, Howard.