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Discussion Starter · #1 ·
Hi to all,

I have a NEC PG-6 PJ for the past 8 years,2500 hrs total.

Lately i have noticed that the red tube started pushing the blacks,i tried correcting with the kelvin button and doing the white balance thing but wasn`t happy with the result.


To get to the point,I purchased the manual and saw the white balance adjustment procedure and thought i could do the correction myself,which ruined the white balance,Grey scale and color balance.

My question to the experts in this forum,if its possible to do my input board and driver board adjustments on a different working chassis and then plug it in my chassis and get a good calibrated projector.


The thing is that i don`t have an expert on this projector where i live,and i`m thinking if it`s possible to ship out only these boards to get them calibrated on a different chassis, instead of shipping out the whole projector .


Thank you,

Yuval.
 

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Odd.... and I had just stated that no one should do this unless they TRULY know what they are doing and have the right tools. Since the calibration has to be done with the tubes used, it's unlikely that any decent results can be achived by the method you suggest. Remember, the G2 settings play a big role in there as well. Most likely you will need to find someone, or ship the projector.


Marc
 

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Discussion Starter · #3 ·
Thanks Marc,

Basic adjustment for cathode swing,cutoff,G1,is fixed regardless of tubes used in any setup.The G2 setting are fairly easy to do.

Correct me if i`m wrong.

Yuval.
 

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Yes and no.

I just went through this and flew a tech into help fixed this. He requested if he could try to do a positional setting of the pots based on what he got from another projector. I said okay and we got very close. Please note though that the actually procedure is very long and need an oscillascope to get the proper White and Black settings and the voltages correctly (nothing to do with the G2 settings).


Good luck (just get a Tech).


clopez
 

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Yuval, you are corrected. The NEC is the exception when it comes to G2 settings.


Marc
 

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Discussion Starter · #6 ·
Marc,

If i only had the Video signal generator and portable scope to try and dial it in,But i don`t have it.

I`m not using the PJ because i fear overdriving the CRT`s to a point of destruction .

Do you know of an NEC PG6 expert that has a working chassis and can and willing to take my driver and input boards for calibration on his chassis ?

If it will need a small G2 touch-up on my side,i don`t think it will be a problem.

I have learned by now what not to touch.


Yuval.
 

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Marc,

Quote:
Originally posted by Tinman
The NEC is the exception when it comes to G2 settings.
I've had a Kloss Novabeam 100, NEC DP1200S and my current NEC 9PG Xtra. I've never had much problem in the adjustment of the G2, but would suggest that they are sensitive and difficult to adjust (particularlly to move the pot back to the same positions)


But, why do you consider NEC's (or is it just the PG's) harder to adjust than others? What is the difference for others such as Barcos, Sonys, ECPs etc.


Thanks,


Ira
 

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Ira, I've obviously opened a can of worms here, and regardless of what Doug, Curt, or myself have to say about this subject, someone will always argue that it can't be that hard, other projectors aren't that hard. Until they try it... :) This particular adjustment is specific to the PG and XG series of projectors. What sounds straight forward at the surface is actually a series of adjustments that all affect one another. Unless you have mucked around with it, and then tried to get it right, you probably cannot appreciate why on earth NEC came up with this one. I also had a Novabeam, several sony's and some Barco's. Even a GP3000. All a breeze to dial in compared to the PG and XG NEC's. Most projectors you dial in the G2's for black, and the drives for white, and that's pretty much it. NEC's use a base cal for the G2's, then another for the reference black/white balance, and yet a third for the "Normal" user adjustable reference. The adjustments are so fine, you need a scope to do them right. Very complex machines, but maybe that's why it produces such a stunning image.



Marc
 

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I adjusted the G2 on my XG1350 recently, using only the instructions that KennyG posted here recently. I'm pretty much a newbie when it comes to CRT projectors, but I am fairly handy.


Anyway, I didn't think it was that hard, just a little tedious and time consuming, but not difficult. If I can do it, anyone can!


Having said that. all of my voltages at the test points were within spec with the test switch set to "Test", and I'm sure that if they are not, then it would be very difficult. But until you test them, you don't know!


Regards


John
 

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That's true, if the basic adjustments have not tampered with, you can get the G2 back where they should be. But if someone turned every pot in there.... watch out :)


Marc
 

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Discussion Starter · #11 ·
Back to my original point,

Is it possible to do a driver & input boards calibration from one PJ on a different chassis?,return them to their original PJ and get a calibrated projector?

The G2 issue dose not interfere with the boards basic adjustments and can be restored later on without any difficulty,If the boards are known to meet the specs.

I`m in a situation where shipping out the projector two way is around $1000- (By sea,around 2 months),Compared to shipping the boards by Air round trip for less then $75-.
 

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And again,

it will be cheaper to fly a tech (who have worked the model) to redo the video board back into spec and do a ISF calibration at the same time.

Once you have messed with the video output board you will notice that some movies look good while in others the color will be off. I have messed with that board before and have tried to get it back into spec by myself. These are very sensitive adjustments.

Read my post that is what we did. There was a side effect when setting them using another machines settings


clopez
 

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Discussion Starter · #13 ·
clopez,

using another machine settings is not the same as calibrating the boards on a different machine,Your board may not be identical to mine in 100% due to components variance,But using and calibrating the complete signal chain,From RGB-HV input to the CRT feed,of both boards on another machine seems to me as a valid solution.
 
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