kentmurphy
Well-known member
Folks,
Looking for some advice. I have a TM202G monitor which is missing the color green.
I hit the tube with my CRT analyzer (Senscore CR7000) and all the guns are good.
I adjusted the green contrast pot and there was no change.
I recapped the monitor, but that did not resolve the problem.
I pulled and tested the green driver transistor (Q352) on the neck board and it tested fine.
I then decided to do some probing with my multimeter and compare the readings to a working Matsushita. I connected the black lead on my meter to pin 3 (see black arrow) of the connector on the video amp board. Next, I connected my red lead first to N12 and then to N13 (see red arrows).
https://skydrive.live.com/?cid=4127...cid=4127EA3A33B50049&id=4127EA3A33B50049!3773
https://skydrive.live.com/?cid=4127...cid=4127EA3A33B50049&id=4127EA3A33B50049!3772
The reading on the good monitor at N12 was ~4.5 vdc while on the non-working monitor it was 1.7 vdc. The interesting thing is that the readings for the other colors were also lower (~2.2 vs ~4.5 vdc) when compared with the working monitor. Yes, I realize the voltages from the game board can change as the intensity of the color changes, but I took my readings during the same point in the attract mode sequence.
Now for the questions. Am I overlooking something? What else can I do? Would you agree the problem seems to be isolated to the video amp pcb?
Thanks.
Looking for some advice. I have a TM202G monitor which is missing the color green.
I hit the tube with my CRT analyzer (Senscore CR7000) and all the guns are good.
I adjusted the green contrast pot and there was no change.
I recapped the monitor, but that did not resolve the problem.
I pulled and tested the green driver transistor (Q352) on the neck board and it tested fine.
I then decided to do some probing with my multimeter and compare the readings to a working Matsushita. I connected the black lead on my meter to pin 3 (see black arrow) of the connector on the video amp board. Next, I connected my red lead first to N12 and then to N13 (see red arrows).
https://skydrive.live.com/?cid=4127...cid=4127EA3A33B50049&id=4127EA3A33B50049!3773
https://skydrive.live.com/?cid=4127...cid=4127EA3A33B50049&id=4127EA3A33B50049!3772
The reading on the good monitor at N12 was ~4.5 vdc while on the non-working monitor it was 1.7 vdc. The interesting thing is that the readings for the other colors were also lower (~2.2 vs ~4.5 vdc) when compared with the working monitor. Yes, I realize the voltages from the game board can change as the intensity of the color changes, but I took my readings during the same point in the attract mode sequence.
Now for the questions. Am I overlooking something? What else can I do? Would you agree the problem seems to be isolated to the video amp pcb?
Thanks.