View Full Version : 8 inch RCA


timmy
12-19-2017, 02:59 PM
Anyone know an easy way to adjust the ion trap magnet without taking the whole set apart ? :scratch2:

jr_tech
12-19-2017, 03:43 PM
Possibly by removing the antenna, one can reach in with needle nose pliers and grasp the cardboard tube that surrounds the neck of the CRT well enough to turn it to adjust the trap. Otherwise remove the chassis from the can.

jr

timmy
12-19-2017, 04:23 PM
The cardboard is used to move the magnet ?

jr_tech
12-19-2017, 05:35 PM
Yes...Phil N says it far better than I can.

"On this set, the ion trap is adjusted by manipulating a little metal collar around the neck of the picture tube. A stiff paper sleeve is provided to let you do this without poking instruments down into the narrow space between the picture tube neck and its surrounding metal shield. The paper immediately broke when I tried to move it, however, so I ended up poking a long crooked-neck tweezers in far enough to reach the metal collar.

Sure enough, when I pushed the collar in, the picture immediately grew brighter. Working a bit at a time, I adjusted the trap so that the picture had normal brightness."

From https://antiqueradio.org/rca16.htm

jr

Eric H
12-19-2017, 07:34 PM
It’s Fish Paper as i recall, and always brittle
After 60 years.

jr_tech
12-19-2017, 10:20 PM
Yes it is brittle, but with some care it can be pushed pulled and turned on the neck of the CRT.

https://farm5.staticflickr.com/4635/39142245582_f2365380d0_z_d.jpg

jr

.

MadMan
12-19-2017, 10:55 PM
Can you gently pull it out completely and replace the cardboard with new cardboard?

timmy
12-20-2017, 05:06 AM
Can a different magnet be used, since I have another one from another set with the 14 inch tube and the neck is the same size. It would be easier to use the one I have instead of the one that came with the set. Just didn't know if these magnets can be interchanged. :scratch2:

stromberg67
12-20-2017, 10:16 AM
Antique Electronic Supply tubesandmore.com sells GC fish paper, which is what you need to replace the aged paper under your positioning magnet assembly. I have used it in two of my 8 inch RCA "personal portables". The AES item number is : 005759. The GC number is : S-M 560
Kevin

Eric H
12-20-2017, 10:48 AM
I doubt you can substitute another magnet, besides the physical size, this is a very weak magnet and a bigger one may not be compatible with the CRT.

The reason it has to be adjusted with the set assembled is that the metal shield around the neck of the tube can affect the magnetic field enough to throw the adjustment out of whack.

I fought a set for hours once because it would work when apart but not when assembled, it was the metal shield messing with the Ion trap.

timmy
12-20-2017, 06:55 PM
Ok so I didn't use another trap I used the original and what I did was grab the paper sleeve and pulled the whole thing out but not befor I put a mark to line up with a pin. I had a cloth with furniture polish and wiped the inside of the paper sleeve and then put the cloth down in along side the crt neck and wiped it then reinstalled the whole sleeve and it glided right down and was able to move it freely with no problem. The brightness is much brighter now, all I had to do is pull it up Alittle bit but maintained the mark I made now it's perfect. It's amazing how this little set works the picture it produces is really clear, probably because it's an RCA , made better. :D