Hi all, first post here.

A few months back, I acquired what was essentially a “new” Sony G90, still in its original shipping container, with only about 6 hrs on it from a quick run through by the seller. It seems to function normally with the exception of a color issue that I cannot seem to resolve. The overall image has a slightly purplish cast to it. This remains the case at any color temperature, as well as with the custom setting done by a professional calibration performed about a month ago. It’s almost looks as if color is missing. It is clearly noticeable on the white warm up screen (which is not affected by the RGB bias or gain settings).

Has anyone else here experienced anything like this, or have any suggestions as to where the problem may lie?

Thanks in advance.

Your green tube is where the problem lies.

If it looks purpleish that means your red and blue are working well and the green is weak.

ORRR The red and blue have too much push on them.

First I'd look for any physcial signs of tube problems. Like moldy glycol or dust even.(Look into the lense with a bright lite)

Then if everything looks physically OK. Its time to make sure it's electrically OK.
And I think g2(white balance) controls would usually be used to sort this out.
Look into this more before doing anything. They need to be set just right. Or any projector won't work at it's best, or for very long.

Could even be your screen? did you buy it or make it? Diff materials reflect different amounts of colors.

Hope that helps!
Rudy

P.S. Some one who knows about the actual g90 will most likley tell you everything you need to know soon.

Posting where you are located is also one of the smartest things you can do.

If a professional calibrator couldn't get it right, he either shouldn't have charged you, or only charged you enough to cover his travel/expenses and then told you what you need to do to fix it - then come back and finish the job.

Doesn't sound very professional to me.

If you are using the component inputs then you might want to have a quick look in that area. I have seen a similar situation to what you have described excepting that the overall colour cast was aquamarine.

In that case it was a problem that had developed in one of the cables itself but it stands to reason that the same problem could have occurred with a bad connector/solder on the unit itself.

I would expect that your calibrator checked this out but you never know (I'll second Mark_A_W's remarks).

edit: Oops, blanked out the warmup screen part whilst reading which, I suppose, puts my post in the category of the Topal anecdote in Notting Hill. Sorry.

What are you feeding the PJ with(VP, HTPC,Moome Card etc.) You might be not feeding it the right colorspace, you may have accidentaly changed from RGB to YPbCr or another one.

Athanasios

I would also check to see if the AKB is on or off. If it is off, try switching it to on for about 20 to 30 minutes as that circuit will reset the G2 levels to where they should be. This is usually only an issue when you install a new green tube with the original red and blue remaining. I remember Cliff having to install an old green tube because he had to send the new green back for warranty work and he was freeking out about how dim the older tube was. But then he remembered to switch his AKB back on for 30 min and it brought the green tube back up to where it needed to be.

Mike

Thanks to all for the support!

Much of the feedback I concur with.

Responding to comments in relative order:

I also suspect that it has something to do with the green tube and/or its associated electronics. It is my understanding that G2 is automatically set with the ABG circuitry and is not manually adjustable. The screen is a solid (non perf) 1.5 gain Stewart. The D-50 previously installed displayed a very accurate color image, so I’m reasonably sure that’s not the issue.

I am located in Westport, CT USA.

Currently feeding HDMI with the Moome IFB-FULLHD 1.3 card with the appropriate internal settings on the projector. However, the problem is consistent across any and all inputs, as well as with the internal patterns and the warm up screen.

I assume that dochlywd’s reference to AKB is what my menu is calling ABG (if I am incorrect, please elaborate). I tried this exercise a few times to no effect.

I have also been in contact with Craig Rounds who is scheduled for a calibration in March if I’m able to sort this out. He had some suggestions as to which boards might be suspect – fortunately I have a friend with 2 other G90s currently in storage so that I can swap them out fairly easily. His feeling was that if they checked out OK, then it was most likely the tube itself.

The only other thing that occurs to me is that it might be a power supply issue – perhaps a just bad cap. When I power up on the warm up screen it sometimes comes up very purple initially and ramps up gradually to white over the first 20 seconds or so.

I'd like to add that the WORST thing you could do here is ASSUME. With RARE exceptions, 'caps' don't just fail, esp. with a brand new set. Best thing you can do is send boards to be tested, either to Craig if he has a test chassis, or to me, as I have a couple here in good working shape.

Guaranteed that it's not the power supply, or anything else common to all three tubes. It's something related to the green circuit only. As you pointed out, it could be the tube as well.

Whatever you do, don't start randomly swapping boards and/or swapping components on a board without a thorough testing/knowledge of what you're doing. If you're going to swap a board, change the RGB input board. I've had one of those cause excessive green before.