Hi,
My first post to KLOV!
I'm trying to solve a CRT issue on my Punch-out!! While running over the weekend, the image on the lower monitor has shifted to the right about 1/3-1/2 of the screen. There's no image distortion, blinking, folding etc. It looks completely normal except it's shifted. In fact since everything happens in the middle of the screen for this game, it's still completely playable.
Adjusting Horizontal Center (VR352) shifts the center of the image, but the border of the image does not shift left, the 1/3 is a hard stop. Difficult to explain but it's clear in the video below. The monitor is connected to the Crafty TPG. The blank area is at the bottom in the video as the monitor is sitting sideways.
A Cap Kit was installed in 2021, and it has been working fine for the last few years. Checked all the resistors and caps around IC401 and everything seems fine. Checking all the components around the horizontal drive circuit has turned up nothing.
Hooking the scope up shows proper wave forms as shown in the schematic.
B+ is another story and drifts significantly above and below 108V. I've ordered a new regulator (IC401) and pot (VR601).
I also ordered a new flyback and IC401; even if these are not the issue, they can be kept for future use.
I haven't taken the upper monitor out yet to compare signals etc., but that may be coming soon.
Any ideas would be greatly welcomed,
Greg
My first post to KLOV!
I'm trying to solve a CRT issue on my Punch-out!! While running over the weekend, the image on the lower monitor has shifted to the right about 1/3-1/2 of the screen. There's no image distortion, blinking, folding etc. It looks completely normal except it's shifted. In fact since everything happens in the middle of the screen for this game, it's still completely playable.
Adjusting Horizontal Center (VR352) shifts the center of the image, but the border of the image does not shift left, the 1/3 is a hard stop. Difficult to explain but it's clear in the video below. The monitor is connected to the Crafty TPG. The blank area is at the bottom in the video as the monitor is sitting sideways.
A Cap Kit was installed in 2021, and it has been working fine for the last few years. Checked all the resistors and caps around IC401 and everything seems fine. Checking all the components around the horizontal drive circuit has turned up nothing.
Hooking the scope up shows proper wave forms as shown in the schematic.
B+ is another story and drifts significantly above and below 108V. I've ordered a new regulator (IC401) and pot (VR601).
I also ordered a new flyback and IC401; even if these are not the issue, they can be kept for future use.
I haven't taken the upper monitor out yet to compare signals etc., but that may be coming soon.
Any ideas would be greatly welcomed,
Greg

