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Old 22nd Jan 2007, 11:44 pm   #1
yagosaga
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Location: Braunschweig, Germany
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Default Another TV22 - Help required, please

Hello, thanks to all which provide so much information here about the Bush TV22 restauration. I have got a TV22 last year (the model with EF91 and PL38/PZ30). The picture tube was dead when I have tested it. Zero emission.
Meanwhile I have removed the waxies on the main deck and replaced them by new capacitors. A first test showed that there was a very dim glance on the screen:
http://bs.cyty.com/menschen/e-etzold...firstLight.jpg
After testing the valves and replacing an EB91 and an ECL80, I got better results:
http://bs.cyty.com/menschen/e-etzold...irstLight2.jpg
Meanwhile the picture tube seems to revive:
http://bs.cyty.com/menschen/e-etzold...irstLight3.jpg
I am not familiar with the British 405 line system. The high voltage seems OK. I took a grounded 1 MegOhm resistor and tried arcing at the anode connection of the picture tube.
The horizontal output unit's frequency sounds like it is running only with 5 or 6 KHz. I have checked the horizontal oscillator, but it seems to be OK. If it is running with half of the actual line frequency, should it operate as well as the photos report?
Here are some more photos:

http://bs.cyty.com/menschen/e-etzold...bushTV22_1.JPG
http://bs.cyty.com/menschen/e-etzold...V22_hinten.JPG
http://bs.cyty.com/menschen/e-etzold...22_hinten2.JPG
http://bs.cyty.com/menschen/e-etzold...22_hinten3.JPG
http://bs.cyty.com/menschen/e-etzold..._Zeilenend.JPG
http://bs.cyty.com/menschen/e-etzold...38gluehend.jpg
http://bs.cyty.com/menschen/e-etzold...V22_signal.JPG

I think that it is not necessary to change all the waxies. On the receiver unit which caps should I absolutely rejuvenate?

Kind regards
Eckhard

Last edited by Paul Stenning; 23rd Jan 2007 at 10:50 pm. Reason: Removed one sentance as requested by yagosaga
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Old 27th Jan 2007, 11:26 pm   #2
Courtney Louise
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Default Re: Another TV22 Help required Please

Hi and welcome.

It looks like a nice set. I dont think the PL38 shouldnt glow blue like that. But it does look like your getting a good result there. I did change all of the waxies myslef, some people do, some people only change the ones that are actually faulty.

If its wax in My opinion its generally faulty, I do have a capacitor leakage tester and every one I removed was faulty. some of these will stop your set working, some like the one accross the power input are straight accroos the live and neutral of the mains pins and very bad if they break. Some will just affect your picture or sound quality.

Good luck and keep the pictures coming...

Andi
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Old 28th Jan 2007, 8:55 pm   #3
yagosaga
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Default Re: Another TV22 Help required Please

Hi Andi,

I would keep the wax capacitors on the chassis as much as possible. In our local collector's meeting, we had a discussion about recapping. The general opinion here is not the change all caps but only the coupling capacitors. Not critical are screen voltage caps and kathode caps with a parallel coil or low-Ohm resistor.
Even with the coupling capacitors you can make a difference: those with a high d.c. difference and a high a.c. component are critical. But those with a small a.c. component like in I.F. units are not so critical. The crucial point is how a capacitor leakage would affect the grid voltage and the working point of the tube.
For example: in the Bush TV22 I would replace no caps on the receiver unit if I have no indication of misfunctioning.

Take a look into the schematics:

https://www.vintage-radio.net/forum/...3&d=1149231487

On the main unit C4, C5, C9, C10, C13, C17, C18, C19, C22 and C28 should be checked for leakage. So, in my opinion, in the TV22 are ten caps at least really critical. C29 is critical of course. But if C29 has leakage current, the fuse will melt. So you can decide to keep C29 until the fuse acts.

Kind regards
Eckhard
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Old 29th Jan 2007, 9:47 pm   #4
Ghostuser
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Default Re: Another TV22 Help required Please

PL 38s can glow blue like that with no problem.
Nigel
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