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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 24th Aug 2011, 9:26 am   #21
Andy Doz
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Default Re: Bush TV12 restoration.

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Originally Posted by HamishBoxer View Post
Think your Frame Osc Tx could be o/c Andy.

David
Hoping it's not ... there's a watty looking resistor that reads upwards of 10Meg, so I'm hoping that's the fault.

PM sent
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Old 24th Aug 2011, 9:31 am   #22
murphyv310
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Default Re: Bush TV12 restoration.

Don't worry about the transformer if it is O/C. Virtually any frame blocking transformer will work perfectly well in a TV22 even ones with wildly different ohmic values.
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Old 24th Aug 2011, 10:38 am   #23
Andy Doz
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Default Re: Bush TV12 restoration.

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Don't worry about the transformer if it is O/C. Virtually any frame blocking transformer will work perfectly well in a TV22 even ones with wildly different ohmic values.
If only I virtually had one
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Old 24th Aug 2011, 11:31 am   #24
FERNSEH
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Default Re: Bush TV12 restoration.

Things are not going well. It is likely that the lack of width problem is the line output transformer.
The TV12 along with earlier models such as the TV1,TV2 and TV11 employ two transformers in the line output stage. One does the flyback EHT and the other the scanning. It seems that the line scan transformer has failed. The boost and scan coil series capacitor have been replaced. The valves are OK.

DFWB.
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Old 24th Aug 2011, 11:45 am   #25
Andy Doz
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Default Re: Bush TV12 restoration.

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Originally Posted by FERNSEH View Post
Things are not going well. It is likely that the lack of width problem is the line output transformer.
The TV12 along with earlier models such as the TV1,TV2 and TV11 employ two transformers in the line output stage. One does the flyback EHT and the other the scanning. It seems that the line scan transformer has failed. The boost and scan coil series capacitor have been replaced. The valves are OK.

DFWB.
That's not good ... can the transformer be "rang" like the usual? (Is that the correct English? ... rang , ringed ? Both sound equally wrong)
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Old 24th Aug 2011, 12:16 pm   #26
FERNSEH
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Default Re: Bush TV12 restoration.

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That's not good ... can the transformer be "rang" like the usual? (Is that the correct English? ... rang , ringed ? Both sound equally wrong)
Or is the word rung? It depends on the tense. Rang sounds OK to me.

The suspect transformer is does not use the flyback pulse in operation. It acts in a similar manner as an audio transformer except it must operate at 10Kc/s up to 100Kc/s.

DFWB.
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Old 24th Aug 2011, 5:13 pm   #27
Andy Doz
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Default Re: Bush TV12 restoration.

Frame wasn't running because R53 was as near to open as can be.

Aftyer some gentle persuasion , I have a picture. Brightness control is open circuit at one end , the contrast control is scratchy and I'm yet to go through the waxy's on the RF deck, but ... it is getting there ....
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Old 25th Aug 2011, 7:55 pm   #28
Andy Doz
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Default Re: Bush TV12 restoration.

I couldn't get the first anode voltage right. I'd missed the cap decoupling the metrosil, hidden under the tag strip. A few more caps and I should be done. Got plenty of contrast now and the tube's lovely and sharp. Linearity is not good as yet.
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Old 2nd Sep 2011, 7:59 pm   #29
BGmidsUK
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Default Re: Bush TV12 restoration.

You could do with another set to try a swap. The tube does look pretty bright in the photo!


Brian
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Old 2nd Sep 2011, 8:07 pm   #30
Amraduk
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Default Re: Bush TV12 restoration.

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That's not good ... can the transformer be "rang" like the usual? (Is that the correct English? ... rang , ringed ? Both sound equally wrong)
It's definitely rung!

Regards,

Dave.
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Old 4th Sep 2011, 6:43 pm   #31
Andy Doz
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Default Re: Bush TV12 restoration.

Thanks Dave. I knew it rang a bell somewhere...

Any update on the TV12 FERNSEH?
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Old 6th Sep 2011, 9:46 am   #32
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Default Re: Bush TV12 restoration.

Hi Andy,
The line scan transformer is definitely suspect.

I will be out of this shop for quite some time so no restorations will be done in the near future.
There's plenty of jobs to do when I return.

DFWB.
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