CurtPalme.com Home Theater Forum

**Curt Palme**

Got an email from a customer today that retubed his set with new LUG tubes.

He says that he cannot get the core of the defocused beam to center in the dot. He's at 254, and while the core moves left to right as it should, he would need to be at about 300 to get it centered.

vertical centering is fine.

He didn't remember the old tube doing this, then again, like most others, I'm sure he didn't check that prior to retubing, since his tubes have wear. Since the H circuit works, I don't think this is an electronic issue within the set. I can get him to swap the end magnetic coil between tubes maybe, but I have yet to have a coil issue like that. Bad electron gun manufacturing maybe?

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Turn the astig yoke around the neck.

kabuby77 · Joined: 28 Mar 2011 Posts: 147 Location: Italy

I've got the same problem after installing 6 pole astig magnets. I think it has not mounted correctly, just a small shift makes difference.

CIR Engineering · Posted: Wed Oct 09, 2013 6:09 pm Post subject:

I've never seen this happen before on a G90 Curt. I agree that the most likely thing is a bum tube or cracked ceramics inside the gun. Have him pull the magnetic off the neck and look for cracked ceramics.

After that, I would try rotating the 2-pole focus coil 90 degrees, changing coils with another tube, and then changing the EBB (and daughter cards) board, then try changing the EBQ or EBH boards.

I'm pretty sure he can swap the EBB with the with the EBG for testing. He can swap the EBQ and EBH boards for testing.

Either that or he is simply doing the 2-pole adjustment wrong.

craigr