You just quadrupled my knowledge of ion traps and pattern alignment, all in half an hour. Thanks, Bob.

Great series, there is just something magic in old tv sets.

Hi Bob, thanks for explaining the Ion Trap Magnet, I didn't realize it was to prevent the brown spot. My first TV was an RCA 21" with the KCS88 chassis. In 1972, my brother and I brought it home from the dump and I fixed it so we could have a TV in our joint bedroom. (For a kid, this was considered a premium luxury at that time). It had the ion trap magnet and a series of 3 permanent magnets in an adjustable collar forming the focus magnet. The ion trap magnet had a very narrow sweet spot. The centering rings, aluminized CRT, and electrostatic focus on the later B&W CRTs made things SO MUCH easier! It was a bit confusing at first going to Color CRTs since the centering rings were used to set the Purity. I agree with the magnetic field problems upsetting the electron beam plus, it interfering with the CRT shadow mask. Those round 19" color CRTs without a built-in deguasser were super sensitive to the least little thing. I remember working with the customer to figure out where they wanted the TV in their room, then I did the color setup process on the CRT.

That was very, very good. Super informative. And this veteran gleaned some newfound info as well. Thoroughly enjoyable. Thank You, Bob.

EXCELLENT video Bob! I just removed all of this to clean up the Picture tube and was very careful to photograph and document the positioning of all three devices. I even counted exposed threads on the yoke coil mounting screws/nuts to the focus coil. Now that you've presented this, it makes perfect sense and, should I be lucky enough to get any life out of the T1401, I might be able to make proper adjustments to these components. Thank you!

Another great video! Very interesting and instructive. The demonstration of the adjustments in real time is invaluable. Thank you.

in the time of tube TV a static distortion pattern would appear on the right and left sides of the CRT tearing up the picture vertically. it was a high voltage parasitic oscillation. The field cure was placing and adjusting a small Ion trap assembly in the middle of the HOT tube. I learned about Monochrome Television thru RETS electronics Technical School in a formal classroom setting. In the afternoon we would go to the TV lab to work on old Motorola chassis. I learned the basics there. It was in the shop and field as an apprentice that I was taught all you are teaching here. I spent 20 years in TV and Radio repair, then taught classes at night for Sylvania Technical School. I no longer delve in TV service and I find it interesting that now it is a full time hobby and business. Keep up the good work !

This series with your explanations is awesome. Thank you.

Very interesting. I never knew that a misadjusted ion trap could destroy the CRT.

Bob super great video nice series learning so much and so helpful so glad to watch a few times to learn all I can, but really enjoy your channel My favorite. Always waiting for each new one and watch some re runs. Many thanks Mike

Nice job. We just called them cathode guns. We used to have Hawkeye regun our tubes on ours. We used to rebuild 10-15 monitors each week since I worked in a major satellite broadcast studio maintenance department. Later, color sets, but our jobs were eliminated slowly to flat screens then LCDs. The big problem was sometimes the speakers in the cabinets of monitors and EMI from the HV leaking into audio in edit rooms. I learned electronics in the 60s and 70s and worked on Tek 445 and Hp scopes when i worked in metrology my early days. What memories you just brought back. It makes so much sense hearing what you said.

This is excellent. Keep doing these videos.

Some tubes also had a beam shaping magnet, which could adjust the shape of the electron beam, to help create a sharper picture.

How do you know all this stuff so well? Is this just a passion? Or has it been your profession as well? Very, very cool.

Sony used to supply a bag of self adhesive magnetic strips to attach to the CRT bell for ultra precise convergence on their broadcast grade monitors. You used them as the last steps. In reality I don't many people did! Note that Sony broadcast grade CRTs were plain old consumer tubes. They were just hand picked for the best parameters.

There's a trick which should help with initial positioning of the ion trap magnet: The electron gun assembly should have two "flags" and the black-covered support of the magnet should be lined up with these. This was taken from the Emerson 571 factory manual.

When and how did they get rid of the ion trap on CRTs? My 1955 RCA has a replacement CRT from 1965 with no ion trap.

How did aluminized CRTs effect needing an ion trap magnet?

Great informative video. How strong or detectable is the single magnet type ion trap strength supposed to be? ie. will it noticeably draw a screwdriver tip to it? I restored an Admiral 20X122 with 10BP4 with a single pole ion trap magnet and the magnet has zero detectable magnetism. I have not been able to find a replacement single magnet type. The set does produce a picture and the magnet does affect the brightness a little (but not like in your demonstration) so there must be some magnetism remaining, however the brightness is rather low. No burns on CRT. No geometry or focus issues. Can a double magnet ever replace a single magnet? -Erik

What's with your calibration grid? Is it hand drawn? Or are the lines not straight because of some imperfection in the shape of the CRT?