I have a Dell P991 which is tripping when first switched on. It trips maybe 5 times then shuts down completely. I checked various diodes and transistors both on the secondary of the power supply and around the LOPT, all seem ok. I can monitor the voltages from the power supply secondary and they are all about 75% of the expected voltages, obviously due to the tripping, before shutdown occurs. The tripping occurs immeadiately on power up, and there is no degauss noise or eht build up before the trip occurs.
Anybody had a similar problem?

Chris

Possibly a bad flyback, its a very common failure in this monitor. Its nla from Sony, but I have some good replacements in stock for purchase. Email me for more info.

Steve

I purchased the replacement flyback transformer as you suggested. This got the monitor working, thanks. However now the screen is a little too bright compared to before the tripping issue, and also the picture is out of focus, but only around the edges of the screen. The center is fine. I've tried adjusting the two focus pots on the flyback with no improvement. Any suggestions? Could I possibly have a incorrect or bad replacement transformer?

For the brightness issue, try using the Image Restoration feature in the Options menu. Note that the monitor must be operating without going into power save mode, for at least 30 minutes before this feature is available.

For the focus issue, try reversing the connections of the two focus leads from the FBT to the CRT socket.

poosibly a bad contact.
Look carefully on solderside there is a small breach just below the power transformer.
Because you say the voltage is too low ,there is badly regulation of 200 volts.
the breach you can recognize as a black dirt (corrosion of a rubber spacer kitted on metal chassis
exactly below the power transformer.

3 of 5 P991 has this problem.

kickstarter

Your problem lies in the input ac socket.
Try changing the ac socket.
Mine also trips because of the faulty socket.