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  #1  
Old 11-06-2011, 01:29 PM
Nuke Nuke is offline
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Will running a set without a HV Cage affect performance?

Greetings -

Working on this Admiral 20x1 chassis without the hv cage. Just curious, will this cause interference in the way the set runs? I just recently was able to get a raster and audio after a recap but the display is not stabilized.
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Old 11-06-2011, 03:34 PM
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bandersen bandersen is offline
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You might get some interference in the picture, but I wouldn't expect the sync circuits to be affected.
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  #3  
Old 11-06-2011, 04:23 PM
old_coot88 old_coot88 is offline
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Having the HV cage off is not likely to affect the set's own performance, but will allow a lot more RF to be radiated by the flyback, the harmonics of which can play hob with nearby AM radios.
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Old 11-07-2011, 07:09 AM
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earlyfilm earlyfilm is offline
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Quote:
Originally Posted by Nuke View Post
Greetings -

Will running a set without a HV Cage affect performance?
Well, that depends.

If you mean the set's performance, No.

If you mean your performance, Possibly Yes.

The cage is there primarily to shield humans from X-rays, not to prevent interference.

I'd recommend limiting your exposure to X-rays as much as possible while servicing the set. Unless I am checking for arcing inside the cage, I'll usually stick the cage back on with just enough screws to hold it in place while working on the set.

Jas.
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  #5  
Old 11-07-2011, 07:46 AM
old_coot88 old_coot88 is offline
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Darn, I shoulda been croaked many moons ago from Xrays and all my kids born with six fingers and toes.

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Old 11-07-2011, 08:44 AM
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Zenith26kc20 Zenith26kc20 is offline
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Only ones I find sensitive are the electrostatic sets like the TS-4 Moto's. They seem to get upset.
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  #7  
Old 11-07-2011, 10:24 AM
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Tom Albrecht Tom Albrecht is offline
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Sets with an RF high voltage supply (which includes all the early electrostatic sets, but also a number of other early sets) can have interference in their own pictures when the HV cover is off. Sets with flyback HV supplies don't have this issue.

As others have stated, safety and x-rays, however, are good reasons to make sure the HV cage is in place, even if there is no interference.
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Old 11-07-2011, 07:45 PM
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M3-SRT8 M3-SRT8 is offline
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Yup. And some TV's HV cages have magnets attached to eliminate the Barkhausen Effect. My DuMont RA-103, for example...

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Old 11-07-2011, 08:27 PM
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Sandy G Sandy G is offline
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Quote:
Originally Posted by old_coot88 View Post
Darn, I shoulda been croaked many moons ago from Xrays and all my kids born with six fingers and toes.

You mean you're NOT sposed to have 6 fingers 'n' toes ?!?
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  #10  
Old 11-07-2011, 09:28 PM
Nuke Nuke is offline
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Well another forum member is forwarding me a cage which I am awaiting. My biggest concern is obviously the shock hazard. That's generally why I don't like to work on sets when they are running. I knew that (color) sets had the potential for generating x-rays when run over voltage especially when over 30kv. I think this set's tube is rated at 9kv and I'm not sure it's even getting that high. It is using a 1x2 rectifier tube.
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  #11  
Old 11-08-2011, 11:33 AM
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It depends on the set.... A 3" Pilot won't work at all with the HV cover off, based on one I worked on forever before figuring that out. Probably the proximity of the CRT to the FBT. Others will work, but with color sets, it will allow X-ray escape. Not that I'm one of the believers in any bodily harm from TV X-rays, but it's probably just wise to keep the box closed on color sets.

Charles
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