Been debugging this MS2930 that crapped out on me a week into getting a Blast City (you can read more in my project showcase thread). I have a thread going with Grantspain on the Arcade Otaku forums but might as well get more input here.
Originally the monitor was showing no video or static on the screen. Before it died it seemed the protection circuit was engaging as it would flicker as if the power was being pulled before going back to normal. I did a clean and recap, as well as resoldered the CRT pins. Checked the HOT and vertical IC and there didn't seem to be any shorts.
Figured out that with a video cable plugged in the CRT will flash white for a moment before shutting down so the tube seems fine. Got static too! Finally probed the EHT and found out it was hitting up to 32kV before X-Ray Protect shut down the high voltage (I assume).
TP3/Fuse for B+ was a bit low (170ish) and set it to 180.02v exactly, but the issue still happens even with SCREEN and Contrast pots to low. Interestingly B+ stays active so I assume XRay Protect acts differently to power protection? Also the yoke is arcing with the back of the tube (but there are no arcs inside it). I assume this is due to the HV.
So what are people's thoughts on what is going on?
Screen Flash:
View: https://www.youtube.com/watch?v=2s9rkmXjGkQ
EHT voltage reading:
View: https://www.youtube.com/watch?v=_nLdikXLTUM
Originally the monitor was showing no video or static on the screen. Before it died it seemed the protection circuit was engaging as it would flicker as if the power was being pulled before going back to normal. I did a clean and recap, as well as resoldered the CRT pins. Checked the HOT and vertical IC and there didn't seem to be any shorts.
Figured out that with a video cable plugged in the CRT will flash white for a moment before shutting down so the tube seems fine. Got static too! Finally probed the EHT and found out it was hitting up to 32kV before X-Ray Protect shut down the high voltage (I assume).
TP3/Fuse for B+ was a bit low (170ish) and set it to 180.02v exactly, but the issue still happens even with SCREEN and Contrast pots to low. Interestingly B+ stays active so I assume XRay Protect acts differently to power protection? Also the yoke is arcing with the back of the tube (but there are no arcs inside it). I assume this is due to the HV.
So what are people's thoughts on what is going on?
Screen Flash:
EHT voltage reading:
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