They could be that fragile, it depends, obviously one of them was fragile enough to short in the first place. Now that you have two guns with issues, there's no sense trying to isolate the heater because the guns would just short to each other.
Intermittent fault in Eizo 19" T766 CRT
Apr 25, 2008
45 Replies
I can't be sure, but it seems the blue gun has become much less sensitive, and that the problem now is mainly is the red gun. Maybe it's wishful thinking, because that would mean that it was some dislodged particle, but I'd rather not assume the worst yet, so...
Would anyone know if trinitron tubes have particularly fragile heater/cathode constructions?
The repair FAQ has a comment about having to tap the neck quite hard: "not enough to break it, but close". How fragile is the neck? It would be difficult to describe how hard I could hit it without breaking it, but any advice is welcome.
I've got an additional question. When I put my continuity meter on the GND and R or B pin, I can't produce a short by any amount of tapping. A very brief intermittant short should be very clear, because it has an audible beep. Because I can only reproduce the fault when it's cold, having the heater turned off would seem ideal.
What I want to do, is remove the neck board and do some more testing. Do I need to discharge the tube for this? I would guess not, but I thought I'd ask.
On Ground, or on one of the heater pins?
You might wanna just leave well enough alone and use the monitor the best you can as it is.
Neither produces a short. But the heater and GND give me 1 ohm resistance, which I guess rises when it heates up. So in cold state, measuring between heater and a gun and GND and a gun is about the same.
I can't think of another way for the gun to be fully turned on when it's not connected to anything, but the multimeter hasn't shown a short, which is strange. You wouldn't know of any other possible cause, would you?
The red gun error is quite severe at the moment. It also keeps shutting down when it occurs, so it's not very usable. I don't understand BTW why it does shut down when red is shorted, and not when blue is shorted. It can't be because the driver output is shorted, because I disconnected the plug for it...
Another question: is it bad for the cathodes to run the tube with the heater disconnected? I would like to do some measurements, but I'd rather not keep the monitor on while the cathode(s) is/are being shorted to the heater.
If I keep G1, G2 and GND connected, is that enough to prevent damage to the tube?
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