NEC FP2141SB

[Jim 6787]

One Black bar , then goes to completely black screen comes back ok and then out again ..suspect capacitor in power supply of monitoe opening up does this monitor use half wave rectification in the pwoer supply

 

[nhasian]

yes replace your monitor.

 

[Jim 6787]

yes replace your monitor.

You must be kidding..Replace the monitor ...which cost $1000
So if you car does not start replace your car...certainly a very technical answer..you should be able to assist many with answers like that..Thank you so very much for your answer....I wonder if Tom would agree with you I do not think so..!!!!

 

[Watts Up]

necro thread, but in case it's still relevant to anyone:

I have the same model on my bench and am currently troubleshooting its power supply. I inadvertently ran across this thread while shopping for replacement components.

A brief overview:
This model uses a fairly typical (for quality CRT monitors) SMPS with a GBU6JL full-wave rectifier and a MC33262P PFC for active harmonic suppression. A MIP2E3 IPD generates subpower (MPU 5v) and Vcc (18v sub xfmr tap) to a STRF6676 quasi-resonant flyback pulse IC. Output from the SMPS FB secondary is monitored by a KIA431, which feeds back to the STRF6676 via a TLP721F opto-isolator, thereby controlling the STRF6676's duty cycle for regulation.

If the above language is unfamiliar to you, then I strongly advise you to avoid digging around in high voltage monitor circuits, for your own safety.

While bad caps do cause problems in power supplies (high ESR is common), the OP's particular sporadic/intermittent symptom suggests the culprit could be something as simple as a cold solder joint or a loose ground or cable connection. Slap the sides of the monitor and see if the display changes. If it does, congrats, it's a cheap fix.

Should the OP decide to pay for repairs and the estimate is high, he should weigh the potential return on his investment. For example, has the monitor ever needed Constant Brightness compensation? If this has been done, it's a sign the CRT's cathodes are wearing. If it's been done more than once (I also own this model and have used CB at least twice since 2003), it's a sign there isn't a great deal of life left in the guns, depending on how the monitor is used.

CRT's don't last forever -- they work by continuously burning off gun cathode material, after all. I also hate the idea of replacing mine with an LCD. I had hoped mine might produce a quality image till OLED's hit the shelves, but it likely won't at this rate.

I don't know where the OP bought his for a grand, but mine was only $650 brand new in 2003.

Incidentally, the NEC FP2141SB has the same guts as the more expensive Mitsubishi Diamond Pro 2070SB, so the above circuit description also applies to the latter (for owners of the 2070SB who may find this thread). The NEC is merely rebadged; the Mitsu was sold primarily to commercial/industrial clients at a markup (often with a hood and color calibrator).