1986 NEC Monitor PM1971A

[mattdill]

Dear Video Karma Techs, I am searching for help in finding available parts for what looks to be a transformer issue for my 1986 (NEC)PM1971A , 19 Inch monitor that operates a1980's Las Vegas gaming laser disc machine. The CRT Monitor flashes for only a second then goes off which seems to be a safety issue for the transformer. I contacted NEC and they have no information to share concerning schematics or compatible LED monitors for this unit or any parts to replace the transformer issues which i believe it to be, but i am not sure. Iam willing to buy a another working NEC 1971A Monitor, but none are available as i have been searching for months now. Can Anyone help me to locate either this monitor or the parts to fix this unit which is worth a considerable amount of money in operating condition. Thanks Again

[dbc58]

I believe it has a switching power supply. It's more likely that you need to re-cap the power supply than replace the transformer.

[mattdill]

Thanks for the reply. Does anyone have this unit NEC PM1971A Monitor for sale? Please let me know.

[jbattles]

it might be going in hv shutdown. Look for a diode coming off the fly back. De-solder one end and lift out of circuit. if it stays on there's a short some where or the diode is bad, but it would tell where to look and us old techs can direct you in the right direction.

[mattdill]

thanks for the info jBattles. since these are all japanese parts that are hard to find, will i run into another issue finding compatible parts ?

[jbattles]

no you shouldn't, if it comes on and stays on look at the screen see if theirs a line, if is look in vert circuit, if you have full raster measure the voltage on the collector h-output transistor. voltage should be around 130-140 for 3 leg maybe 160-170 if its two pin metal case, if it is high look to the power supply of improper voltage regulation, also if the CRT is worn it pull to much voltage and it will go into shutdown.