Featured
Latest
Share:
Notifications
Clear all

Forum 141

B&W TV Ion Trap query

6 Posts
5 Users
4 Reactions
299 Views
Doz
 Doz
(@doz)
Posts: 1535
Prominent Member Registered
Topic starter
 

Now we've all been told that an incorrectly adjusted ion trap in a bent gun tube can cause damage.

What I would like to know is the mechanism by which this damage occurs. What is the symptom? Is the CRT emission harmed after being run with an incorrectly set trap? How does the damage occur? Too many ions hitting the phosphor? 

I'm struggling to picture what would happen.

Over to you ...

 
Posted : 25/05/2023 7:04 am
slidertogrid
(@slidertogrid)
Posts: 1114
Prominent Member Registered
 

Ion traps are a bit before my time so I may be wrong but as i understand it you set them for maximum brightness. Otherwise not all of the electron beam is hitting the Phosphor and as a consequence the tube is being run harder thereby shortening it's life. 

Same as the tubes were alleged not to last as long in sets like the KB deep scene where there was a tinted screen in front of the tube meaning the viewer turned the brightness up.

 

 
Posted : 25/05/2023 7:29 am
peterscott
(@peterscott)
Posts: 1028
Honorable Member Registered
 

There are two different types of ion trap. With the bent gun type I don't think there would be any damage due to wrong adjustment of the magnet as the ion stream will still be aimed off screen. The other type has a straight gun but with a diagonal slot between anodes so a maladjusted magnet could cause the ions to hit the screen. 

Peter

www.nostalgiatech.co.uk

 
Posted : 25/05/2023 7:40 am
Nuvistor
(@nuvistor)
Posts: 4623
Famed Member Registered
 

@doz 

Nice write up with photos of the damage to the electron gun assembly in Radio and Electronics, April 1955 page 64.

https://worldradiohistory.com/Archive-Radio-Electronics/50s/1955/Radio-Electronics-1955-04.pdf

Frank

 
Posted : 25/05/2023 10:15 am
slidertogrid, LSmith, Lloyd and 1 people reacted
Doz
 Doz
(@doz)
Posts: 1535
Prominent Member Registered
Topic starter
 

Posted by: @nuvistor

@doz 

Nice write up with photos of the damage to the electron gun assembly in Radio and Electronics, April 1955 page 64.

https://worldradiohistory.com/Archive-Radio-Electronics/50s/1955/Radio-Electronics-1955-04.pdf

Thanks Frank, perfect !

 

 
Posted : 26/05/2023 6:59 am
Lloyd
(@lloyd)
Posts: 1957
Prominent Member Registered
 

That is good, I’ve always wondered how exactly it should be set up. I haven’t encountered a tube with the glow in the neck when setting it up, sounds a useful feature though!

Regards,

 Lloyd 

 
Posted : 26/05/2023 9:20 am
Share: