HP 7540 MONITOR

[tendi]

My monitor HP7540 is not showing a clear picture, it is de-focussed. The focus pot(fbt) is not very effective. The other problem is that the monitor takes too long to get to its brightness and contrast level. And when it does, the contrast will be less than normal. What could be wrong and can i get a schematic for this monitor?

tendi1966@yahoo.co.uk

[fa_07]

hello.
try to regulate flow and the luminosity and the contrace, by regulating the variable resistors of the VHV (with one turns vice)

[tendi]

[fa_07]

salut.
excuse mopi je ne métrise pas l'anglais
il faut ouvrir l'écran, et dans la carte mére de lce dernier y a la THT,c'est le plus grand dispositif noir,il est entouré par une plaque métalique b(masse).
alors sur la THT ya trois résistances qui se trouve sur la même verticale,comment on repère ces resistances?elles resemble aux vices.éssayez de regler doucement.

[torbjorn]

Most likely, those symptoms are due to a worn-out CRT or perhaps that the heater voltage is too low.

The heater voltage is normally 6,3 V or 12,6 V , you can measure it at the CRT base. Note that it is in some cases DC, in other cases it might be an AC impulse voltage derived from the horizontal deflection, in that case you need a good DVM with "True RMS" capability to get a correct voltage reading.

In case of a worn-out CRT, it is not worth repairing the monitor.

[SZASZ]

Hello,

Try resolderind the FBT pins.

And then try to adjust focus.