[giacocasa]

I'm going mad with my first CRT-projector a Nec PG-6000, with no signal input I'm not able to cut off the green CRT .


It's still shining, I have normalized everything in the setup procedure and haven't adjusted any of the pots. Switching the AKB-switch on the video board in testposition the green CRT shines brighter and I see some thin diagonal lines on the screen (top left corner down to the right corner).

Are these retracing lines?


When the testswitch is in normalposiotion I'm able to dim the green Tube a little. In one answer of an earlier posting I have found that there is a possibility to switch the connectors between the green and red CRT.

Which are the connectors I'll have to swap between the red and green CRT PB???


Perhaps this is a solution to isolate the failure in the electronics???


Another question is where I can find a measure point for the G2 voltage on a Nec PG-6000??


Deepest thanks for any help.





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Cheers,


Dirk



Munich, Germany

 

[gn2]

Sounds like you need the service manual. For sale from www.freebrd.com for $10. for a downloadable version.

Personally, I'd simply reduce the screen VR by a very tiny amount, but be warned, I'm NOT a tech and don't know if this is the CORRECT way to fix your problem.

What I do know, is the process for setting G2 on an NEC is a very involved one, very different than Sony or Barco or Electrohome. As described in the "Board level training manual" it has numerous steps and involves the use of a Chroma meter and Oscilloscope and volt meter( I think).

 

[Tinman]

Indeed a very involved procedure, but I'd guess at this point there is little to loose by turning the green G2 down a hair. A lot of times those pots get moved anyway by someone looking, or by accident.


Marc

 

[giacocasa]

Thanks for taking the time to write. I have the service manual for the Nec PG6000. Paul, the picture size is just in normal condition and the raster is centered in each CRT.

Are the pots for the G2 in the little white box near the blue CRT? Isn't it dangerous to turn down the value for the green tube? I'm a little bit frightened of loosing the whole adjustment for the white balance.

In an earlier postings I've read that there is a possibility to check the electronics by changing some connectors between

the green and the red tube. I don't know which connectors I must change.

Is it right that the retracing stresses the green tube? The shining of the green phosphor is very bright. The video signal is clearly visible but the picture is to green. What is the right way to check the failure sytematically.

Do any of you Nec owners have an idea to solve this problem.

Here in Germany it is very difficult to find anybody, who is able to repair a Nec CRT projector. I'll need your help.



Thanks, Dirk


Munich, Germany


This forum is great a lot of information inside!!

 

[Brian Hampton]

Hey,


By the way, The green tubes usually glows. My green tube glows for some time after I turn the unit off. Also, you are checking without an input but you may have a different situation with an input. In otherwords the black level of a no input situation may be different than one with an input. If your screen is illuminated when you have an input and no source is playing then maybe the G2 or even the brightness needs to be adjusted but if it's just a matter of seeing the green tube glow then I would'nt jump to conclusion that there is a problem just yet.


Just my theory,


Good Luck,


Brian

 

[giacocasa]

Thanks to all who helped me to solve this problem. Turning down the G2 for the green CRT works. Now I can start my first setup!!


Thanks for your help,


Dirk


Munich, Germany