Hi so I recapped a m1296 and everything went well and it worked well for days. I took the bezel off to retrobrite it. I put it back on. Now when I power the unit, you can hear the screen energize for about 5 seconds then there’s a click and the screen powers down. The board stays powered. Power is normal at the 24v tp, unit starts up with all the voltages correct then when the screen powers down the 80 goes to ~14, the 12 goes to ~1.4 and the 100 goes up to about 112. Is this a bad voltage regulator or something?
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There is an X-Ray protection circuit that shuts down the power supply in case the EHT is too high. Do you have a high voltage probe?
I don't but if I did, how would I proceed?
Read the schematics very carefully!
http://www.repairfaq.org/sam/monfaq.htm#monhvshutd
http://www.repairfaq.org/sam/monfaq.htm#monasmdavlt
Is this a Sony display?
Mitsubishi
Ok that doc actually helped the h hold got turned up way to high somehow and it was triggering the hv shutdown. Thanks!
Be careful if you replace the boards outright. There are three known revisions of this monitor.
The earliest revisions had a cyan label on the CRT, which is adjusted to 500V. They also had a different main deflection board. These were in production from the introduction in 1990 until some point in the spring of 1991. I believe these were made through about April or so of that year, but there may be a ±1 month or so here.
The later 1991 models had the same cyan label CRT but a different main deflection board. These were made through at least the end of 1991.
The 1992-1993 models (at least the ones made somewhat into 1992) had a white label CRT with red and blue printing. They run at 400V.
I have noticed issues when swapping between these CRTs. Be aware if they were swapped, you may be having problems.
If you do swap boards entirely, perhaps because the focus/flyback unit went bad, try to swap part for part and stick with a monitor made around the same general timeframe if there is any issue. (Example: I had this go bad in my November 1991 monitor and tried replacing it with one from a 1992, which didn't last too long...I then swapped it out with another November 1991 component...from a monitor with a serial number just a few off from my original...and it wound up being a good match).
These monitors are a gem and a must-have for an LC, so kudos to you for keeping it going. I'm trying to keep nine of them alive myself...all different revisions, too...