Everything was working fine...then one day, TV stopped working. I checked the circuit. Q404 was blown. Changed it. Turned the power ON, it blew again - stupid me. After checking for other shorts, took out all the CRT tube connections from ditstribution block. Changed Q404. Nothing blew. Put in red tube, no problem. Connected blue tube, no problem. Connected green tube, Q404 is shorted. Took out green tube, changed Q404. TV worked fine. Picture is messed up as green is missing but the video and audio otherwise is good.
Checked green yokes (how do you check them?) by switching them with blue one (I always kept the green tube disconnected). No problems. So that means yokes are fine, right? May be the distribution block has a problem and can handle only two tubes at a time. Took out blue one and only connected red and green. Same problem - blew Q404. Gave the boards (only the signal board and the power board) to a friend. Who hooked them up at his shop and said everything is working fine. The only thing to do is to replace the green tube. Ordered one. Replaced it. Turned the power on and the Q404 got shorted! By now, my supplier is running out of Q404! And I am running out of ideas to test. So I seek help. Obviously, there is something about green tube - are you supposed to do something to the tube before you connect it?
What can be the problem? How do I test for it? What am I doing wrong? Any help is appreciated. Thanks
junglee