Bad Philips CRTs.

[dr.ido]

Lately I've been having a bad run of Philips A68ESF002X11 CRTs. I don't know what other sets used them, but these have all been in various Loewe sets (Profil 3272, Profil Plus 3472, Calida 5072).

I accumulated a bulk lot various Loewe sets. So far after repairing 3 I find the CRT is bad or goes bad within a short period of time. So far 2 have developed a shorted red gun (one intermittant), on the other the green gun is shorted.

Has anyone else encountered this or is it just a freaky coincidence?

It's quite frustating as I'm now less inclined to bother with the 4 sets I've yet to look at (including an Art 1 that I was looking forward to getting running).

I don't have a CRT tester so all I can do is hook a suspect CRT upto a good chassis and wait. I though I'd finally found a good one, but it only lasted a few days before the same short appeared.

[zenithfan1]

Are you sure the voltages for cathode and focus are correct on that test chassis? The only other thing I would recommend would be to search the bay for a good color CRT tester.

[radiotvnut]

Sounds like a flash back to the '90's and the bad Zenith CRT's. Even if you have a good CRT tester; the tube may not check shorted if it's intermittent unless you can tap on the neck and make the tube short while it's on the tester. You might try laying the set face down and tap on the CRT neck with the set on. Sometimes, this will knock whatever particle that is shorting the gun down in the tube. The tubes in the Zenith sets would short and take the power supply with it. I got to the point that if I saw a burned up power supply in a '90's Zenith, I junked the TV. BTW, I like the B&K 467, 470, 480, & 490 model checkers. They will check most CRT's (with the proper adapter) and the rejuvenate function will not burn up the tube, unlike earlier models. The Sencore CR70 is another later model that should do well. Even though these checkers cost several hundred to over a thousand dollars new, they can often be found used for less than $100. I suspect they will get even cheaper as CRT based TV's become less popular.

[Kiwick]

Not a coincidence.

Your CRTs are from philips' 45AX series, this was the first Philips CRT with square corners in 1986, they had an all-new gun design and they were a real abortion, 9 out of 10 will have some kind of gun failure ranging from really poor focus to shorts or dead cathodes you can't rejuv. good luck finding a decent one for your sets...

Instead, older Philips tubes, especially 20AX, 30AX and the delta guns were excellent, durable CRTs, i have yet to come across a bad one.