Television and Home Theater

I have a Mitsubishi WS-55511 model that turns on, then turns off within 2-3 seconds. I have read alot of post's on the net about this problem, but I dont know how to check certain componets that I need to. I have the v21 service manual for it, but it does not tell you how to diag. I do have an error code of #23. I have checked every fuse and all are good. I have already replaced the capacitors in the DM but no help.

My Sony KDL-40S2000 TV turns off and back on irregularly.  Sometimes it drops out 10 times in a minute and other times it is fine for days.  When the screen turns off the "on" LED turns off with the screen and there is a sound like a relay cycling. 

I've read other posts in this forum that point to a momentary failure of the undervoltage circuit on the power supply.  When I opened the back to apply the fix suggested, it looks like my system doesn't match the ones from the other posts.

Does anyone have any ideas?

Replaced convergence IC amps with STK 392-150 and resistor RK50,all fixed.