10BP4 Bent Or Straight Gun?

[Tubejunke]

I have an RCA 8T-243 with a 10BP4. I was concerned last year as to the correct type of ion trap for these tubes because my set had what apeared to be an incorrect single field trap. I had to adjust all the way back to the base to get a bright raster and feared ion burn. These tubes supposedly used what is known as a double field trap. Mine was definitly single field. It seems that someone said that if the tube had been rebuilt that it would have a straight gun and an aluminised screen. No trap would be required in that case. My tube sems to have a straight gun and I tried it with no trap and got a raster. I didnt use it for very long because I am still skeptical as to the safety of the tube. Could anyone give me a refresher on this subject since old man winter is about to create old TV time again.....

Thanks

[Chad Hauris]

So far as I know, the bent gun is only used on non-aluminized tubes (the ion trap magnet bends the electron stream back towards the screen, while the ion stream doesn't bend and hits the side of the tube.) I would think you wouldn't have any picture if you left the trap off a tube that needed it as the electron beam wouldn't hit the screen.

[andy]

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[Tubejunke]

Thanks folks! Andy had a good point. That is why the traps are called beam benders by some. I still dont feel at ease. I just looked through the side of the tube to the back of the screen and I only see the same greenish white color as any other tube. No silver. The inside coating on the neck goes up so far it is hard to say how "straight" the gun really is. What you can see of it is nearly straight. I looked at another tube in a working set and the bend in the gun is obvious up next to the base. This tube was not a 10BP4. I wish I could get a look at a working set with this tube and the correct double trap. Again no silver on my screen but I can get a raster with no trap. The raster was distorted as if there is sweep trouble, but still a raster. If anyone has a set with a 10BP4 maybe you could take a look at it for me and see how "bent" the gun is and note if a double trap is used. The trap will be obvious as it is two traps hooked together. I sure would like to be able to feel secure in running this set for more than a few minutes. Also I may need a double trap if anyone would sell one..

Thanks everyone!!

[andy]

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[Tubejunke]

Yes, the gap is at an angle and as I mentioned earlier the internal coating goes all the way up the neck up to around an inch from the gap in the gun. I think I did also say that the gun does not look perfectly straight. I think this tube needs the double field trap just as the specifications call for. Really that would make the most sense. As far as the raster with no trap I dont know what to say. I do remember everything being very off center. I have never seen the set work with everything set up right. What I mean is I have always had the chassis out with the crt shoved through the yoke. The weight of the tube is always on whatever I have laying around therefore the neck is never positioned correctly through the focus coil. I have noticed that moving the tube around has a big effect on the centering as would be expected. I wonder if this misadjustment could give me the "raster" without a trap. You know somehow moving the otherwise unviewable beam into partial view. Anyhow, I guess I will put this thing on hold until I find out something definit and/or find a double field trap. I do not want to ruin what seems to be a good tube. I wish I could trade up with someone who is into RCA roundies. They would already have a lot of the odds and ends like the trap and the correct knobs which I have had no luck finding. To me the set is not the most apealing thing to look at but is considered to be somewhat of a find as far as value. I wanted a roundie but I really want one with the more round look like the 60s color sets. Virginia trades anyone?? No color sets, just a description!