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G70 crt pictures-need help

824 Views 19 Replies 9 Participants Last post by Phil Smith, Oct 10, 2006

kostas999

Discussion Starter · Oct 6, 2006

3

I face a problem with my Sony G70 and I need your advice. I open the projector yesterday to see a movie and my beautiful colors were a mess.

All my picture now is green, even when the projector takes no signal. As you can see in pictures, the green crt is not shutting down like the red or blue in the picture. I try all menu in the projector but nothing happened.

I think the raster in all crt is not normal. Behind the normal picture is another second layer. This is not so obvious in red and blue but as you can see in picture, green has big problem.

I though that the problem was my scaler but I have the same problem using an s-video direct from dvd to G70 (using the internal doubler).

All convergence menu work fine, just with the same problem, not clear black.

Any idea how to fix this problem? Is a board failure? Which board?

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kostas999

Discussion Starter · #2 · Oct 6, 2006

2

more pictures of blue and red. In red you can see again the second layer but its not so strong as the green. I dont know if it is norman like this

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1031

· #3 · Oct 6, 2006

IÂ´m not g-70 expert

but seems to me that there is G-2(screen voltage) issue, did you possible touched on those controls?

Ile

· #4 · Oct 6, 2006

If you haven't messed with board pots like G2, it could be board failure.

I'd swap green and red neckcards first...

kostas999

Discussion Starter · #5 · Oct 9, 2006

I haven't messed with any board , I think its a board failure because the previous day anything was ok.

Where are the green and red neckcards? I can see only 3 very big cards across the board between the tubes. One of them in the left has many chips, the midle has only two huge chips and the other in the right I think is one of the power boards.

You mean Ile one of them or a card in the front of the projector where many cards are? (in the right for power, in the left for taking signal and for scaling. )

The problem is in a power suply card or in another?

Curt Palme

· #6 · Oct 9, 2006

I'm guessing the CPU glitched and the bias and gain controls are out of whack. Try resetting those and you should be fine.

kostas999

Discussion Starter · #7 · Oct 10, 2006

I reset everything (from the remote) but the problem remains. I also switch off ABL from menu but the same problem. I try 50Hz (i use now 75) but the same. The problem is the green tube. Its 3 times more strong because it has this second green layer infront of the picture.

I play with colors, gain and bias but could not trow it away.

Any other sugestion? Is it possible to make a hard reset to the crt or in gain and bias chip?

draganm

· #8 · Oct 10, 2006

Quote:

Originally Posted by kostas999
I haven't messed with any board , I think its a board failure because the previous day anything was ok.Where are the green and red neckcards? I can see only 3 very big cards across the board between the tubes.

It is starting to look like a neck-card and loss of Bias/Gain control . The neck cards are actually clamped to the back-end of the tube. They have a big Alum. heat-sink sticking out of the top. You could try swapping these between the Green and 1 of the other 2 tubes but be aware that if forget to plug in all the wires you risk burning a tube. You might want to remove the big upright card between the 2 tubes you will be swapping cards with to give you more room.

Phil Smith

· #9 · Oct 10, 2006

You say you reset everything from the remote. Do you mean you reset everything to factory settings in the service menu? If not, you might want to try that. Warning: you'll have to set up your projector from scratch after the reset.

When you turn your projector off, do all of the tubes immediately shut down, or do you get a small ball of light that slowly fades away?

techman707

· #10 · Oct 10, 2006

It looks like a shorted tube problem to me. Sometimes you can "burn off" what's causing the short with a tube tester (like a Sencore CR-7000). If the tube was out of the machine, sometimes giving it a rap on the neck (gently) can dislodge what's cauing it.

kostas999

Discussion Starter · #11 · Oct 10, 2006

Thank you for your answers.

I reset everything to the factory setup from the service menu. The projector open and close normal, all tubes together without spot. I never remove any tube . They are new with only 800 hours.

When i play with bias or gain menu I have not the second layer in picture. I just have more green picture because green tube has more light than the others.

I will try to swap the neck cards now.

kostas999

Discussion Starter · #12 · Oct 10, 2006

I just swap the blue neck card with the green. The problem remains exactly the same.

I notice that during movies the picture is inside my screen as usual but this second layer of green is out of screen in both sides.

In the tube takes all the space from left to right . Up and down takes only little more than my movie picture.

techman707

· #13 · Oct 10, 2006

Quote:

Originally Posted by kostas999
I just swap the blue neck card with the green. The problem remains exactly the same.

I notice that during movies the picture is inside my screen as usual but this second layer of green is out of screen in both sides.

In the tube takes all the space from left to right . Up and down takes only little more than my movie picture.

I still say it's the tube that's shorted. It doesn't matter how old (or new) the tubes are, they can always short like that. It's not a G2 problem, it's as though you turned up the brightness to maximum. It lights up the whole raster.

draganm

· #14 · Oct 10, 2006

Quote:

Originally Posted by kostas999
I just swap the blue neck card with the green. The problem remains exactly the same. I notice that during movies the picture is inside my screen as usual but this second layer of green is out of screen in both sides.

In the tube takes all the space from left to right . Up and down takes only little more than my movie picture.

bruce if it was a tube short wouldn't it take up the full tube face no? G2/Gain is usually fed directly from power supply rails and controled by neck-cards. If it's not the card then it has to be a power supply issue?

AFryia

· #15 · Oct 10, 2006

Quote:

Originally Posted by kostas999
All my picture now is green, even when the projector takes no signal.

Had a similar issue.

When I replaced the "C" boards I believe some call them neck boards, I had the two heavier black wire ( yellow and turquoise bands) swapped.

http://www.wideopenwest.com/~aifryia.../WireLeads.jpg

I assume it was a polarity thing and the raster stayed lit even without a signal

techman707

· #16 · Oct 10, 2006

Quote:

Originally Posted by draganm
bruce if it was a tube short wouldn't it take up the full tube face no?

Yes it would.

I guess I don't understand what he's saying then.

GjH

· #17 · Oct 10, 2006

It looks like your green tube spot kill is not working... had the same problem with my red tube. Replaced it with a new red tube from sony ($900) ouch and everything is fine now.

techman707

· #18 · Oct 10, 2006

Quote:

Originally Posted by AFryia
Had a similar issue.

When I replaced the "C" boards I believe some call them neck boards, I had the two heavier black wire ( yellow and turquoise bands) swapped.

http://www.wideopenwest.com/~aifryia.../WireLeads.jpg

I assume it was a polarity thing and the raster stayed lit even without a signal

That can happen, but the reason I didn't think it had anything to do with any wiring is because I thought he said it had been working and when he went to turn it on, this problem appeared. However, I understood him to say the whole raster was lit. If it isn't then it's not the tube.....or polarity.

draganm

· #19 · Oct 10, 2006

Quote:

Originally Posted by techman707
That can happen, but the reason I didn't think it had anything to do with any wiring is because I thought he said it had been working and when he went to turn it on, this problem appeared. However, I understood him to say the whole raster was lit. If it isn't then it's not the tube.....or polarity.

well he did say full raster but full raster is never full tube face (normally). One things for dam sure, G70's are very hard to diagnose, much less repair.

I hope i'm never tempted to purchase/repair them again.

Phil Smith

· #20 · Oct 10, 2006

Quote:

Originally Posted by kostas999
I notice that during movies the picture is inside my screen as usual but this second layer of green is out of screen in both sides.

In the tube takes all the space from left to right . Up and down takes only little more than my movie picture.

That's what my green tube did when the spot kill shorted out.

But wouldn't you expect to see a spot after you shut the projector off? You know...spot...kill...spot kill.

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