CurtPalme.com Home Theater Forum

wassup30 · Joined: 14 Jun 2017 Posts: 30

Just as I was almost done too Sad

lol ..... oh well you guys have been super duper helpful! .. This CRT community is awesome! Special shoutout to cmjohnson for all his help!!!! I'd be punching myself in the face right now if it wasn't for you guys lol :--)

jbltecnicspro · Joined: 23 Apr 2016 Posts: 512

Yes, there is lots of indispensable experience and knowledge round these parts. I hope you get your projector up and working. G90's are pretty.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'm just not getting why it seems that I NEVER encounter a G90 that has any problems at all with the RED tube!

If it breaks it's green or blue.

If it's just worn out, it's green or blue. I've NEVER replaced even a WORN red tube in a G90. And I replace a tube for ANY apparent wear. I have the luxury of a substantial tube stash so what's an 8 to you is "replace that trash!" for me.

And I'm sitting on about three full cases (six tubes per case) of absolutely brand new condition reds!

Blues and greens are in much shorter supply.

crtbilly · Joined: 01 Apr 2015 Posts: 54

This makes me not want to turn my g90 on. How at risk are us g90 owners at this happening.

I wonder if there are other gremlins causing this. I like the pin theory.

What were the other variables.
Did the projector warm-up without displaying an image?
How close was the raster to tube edge?
What was the room temp and was there a ac vent near.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

If you've been running it for a long time, it's probably not going to break. Breaks like these are NOT common
although there have been a few.

EVENTUALLY, something will fail and need repair and EVERY G90 is now at least, what, twelve years old at a minimum?

It's far more likely that something else will fail before a tube breaks.

Just turn it on and watch a movie. Don't worry about it.

My pin theory is not PROVEN and short of obtaining a good thermal imaging camera and looking for a cold spot on the tube
face around a pin, and seeing the tube break under those conditions, I probably wll not be able to prove it.

But I do see some supportive evidence. Every broken tube has the break crossing a pin, of the ones I've seen.

mp20748 · Posted: Wed Jun 28, 2017 3:46 pm Post subject:

If the tube was replaced, was care used in tightening the coils on the neck of the tube. They should be tightened slightly, a little tighter than what you would be able to turn the bolt by hand only.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Agreed. No tighter than needed to hold them in place and keep them from moving on their own.

Squeezing tube necks is probably not a good idea.

A replacement tube has been sent out!

gjaky · Joined: 05 Jun 2010 Posts: 2802 Location: Budapest, Hungary

wassup30 · Joined: 14 Jun 2017 Posts: 30

wassup30 · Joined: 14 Jun 2017 Posts: 30

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Once, I took a really roasted tube and TRIED to break it by overtightening the magnetics clamps.

I have a good strong grip and very well developed forearms (maybe they'd shrink a bit if I had a girlfriend.... Wink

) and I was NOT able to break the tube neck using the size of screwdrivers, hex drivers, etc. that you would normally be expected to use.

I am sure you could break the tube neck if you used more force and larger tools than you'd normally expect, but the tube neck
is actually very strong in compression.

Significantly, I've never heard of a tube neck failing due to overly tightened magnetics. And I've found some on tubes where they were certainly tighter than I'd recommend.

lydmann · Joined: 12 Aug 2006 Posts: 56 Location: Norway

love this video
https://www.youtube.com/watch?v=vCmhC1p5ANw&t=5820s

HaydnG90 · Joined: 22 May 2006 Posts: 1356

Was this a factory tube/LC assembly or a rebuilt one?

I know from personal experience the G90 can be a real headache at times but when its working and properly calibrated the image it produces is sublime. Stick with it and always take things nice and slow. I'm still wowed by what the G90 can do at 1080/72Hz with great Bluray transfers.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I'll be getting the broken tube from him because I need the hardware. In fact, I buy G90 tube assemblies in any condition for the hardware, when I can get them. I like to have stock on the shelf for rapid exchange.

No point in guessing if it's a factory job or the tube was replaced at some point, I'll know when it gets here.

As I've mentioned earlier, I no longer quite trust Sony's way of using METAL spacer pins as they can potentially conduct heat
away from the tube at different rates per pin. I'll use plastic spacers in the future to avoid possibly creating cold spots on the
tube face.

I've never seen any other projectors break tubes like G90s do. I now have personal experience with three such instances, all G90s,
and in every case the break running across the tube face passed right over one of those spacer pins. If it wasn't 3 for 3 I would
not be so convinced that the pins are implicated but at this point I can't think of anything else it might be.

I have the full tube spec documents and the allowable temperature differential across the whole tube face is really not a lot. I can
very well believe that the pins could be coupled between the cooling frame and the tube face to varying levels of thermal conductivity, enough so to cause breakage due to the thermal differentials.

wassup30 · Joined: 14 Jun 2017 Posts: 30

Big shoutout to cmjohnson! ... He sent me a green tube and its easily the best tube in the projector. As for this sony g90 I've been able to completely focus all 3 tubes and converge them but no sooner do I solve one problem another one peers its ugly head into the equation .... ugh starting to think this sony g90 was top 3 for worst things i've ever purchased lol Razz

..... that being said the picture looks pretty nice ... however I have uniformity issues on the screen where parts of the screen now look brighter than others ..... also when I have the all white pattern on the left side of the screen almost has a tinge of yellow to it .... also I can have this thing fully and completely converged .... enjoy a movie and then come back the next day to have a large part of the settings revert on me ..... and believe me i'm mashing the memory button every chance i get during any kind of adjustment!!!

Is there something in the menu or something else I haven't considered when it comes to the convergence issues / color uniformity that I haven't considered?

gregstv · Joined: 27 Aug 2007 Posts: 628 Location: Australia

Sounds like the astig is out. The yellow on white is to do with the blue focus/defocus

wassup30 · Joined: 14 Jun 2017 Posts: 30

I'll double check mg focus with blue .... as a side note has anyone ever had their projector almost flicker like it was being degaussed and lose focus to the point you needed to redo the mgfocus entirely? Seems to keep happening ever since I've replaced this green tube.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I don't want to alarm you unnecessarily but one symptom of an IC421 that's starting to fail is any sort of instability that repeats itself.

HOWEVER, the same symptom can be due to a weak power supply board as well.

AND, the Dallas chip with memory battery should be changed out if it is 10 years old or more. If it starts to lose memory,
it can create a flaky projector that loses settings, where you have to reconverge it even though you just did it, or make any
other adjustment that should not have to be redone.

I know the green tube I sent you is a fresh minty one. No surprise it's the best tube in the unit. I do have red and blue tubes
for it as well if you decide to replace them as well.

I suspect that some of your white non-uniformity may be due to a blue tube that has a bit of uneven wear on it, but only a little bit.
It may actually be hard to see by itself but you see it on a white screen.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Oh, what's the serial number on your unit? The higher serials are more likely to have the newer IC421 chip that never fails.

I think my highest serial number ends in 717 and it has the old style chip but all my units are stable and have enough hours on them that the chips would have failed by now if they are going to. Most IC421 failures occur within the first 500 hours of operation.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I finally got the broken tube today, to salvage the G90 hardware off it for core/exchange.

I found that your broken tube was a P19LCP07 type, which has G2 on pin 6 which is right for anything but a Marquee,
so of course it worked in the G90 but a P19LCP does not have the sharpness potential of a P19LQF (stock G90 tube type) or P19LUG (same as LQF but not a Sony proprietary part number) so your G90 should now be able to achieve slightly greater sharpness than it could with the LCP tube in it.

An LCP is basically "standard" sharpness.
An LUG or LQF is the "improved sharpness" type. It has a finer electron beam aperture and smaller beam spot size.

Check your red and blue tube labels. What kind are they?

If you can't see the labels, what color are the two glass strips on the electron gun assembly at the end of the tube? This LCP had white and yellow strips. If the tube is an LUG/LQF type then those strips will be white and pink/tan. They may also be white and light blue, which is yet another possible color code for an LCP type.

If your red and blue tubes are not LUG/LQF types, then that's another reason to consider replacing them with the proper LUG types. It allows for a sharper, better defined high definition image.