CurtPalme.com Home Theater Forum

Matrix · Joined: 06 Sep 2006 Posts: 123 Location: Indianapolis, IN

Ceiling mounted Sony G-70, the tubes are VDC and low hours since I had them installed. Terry setup the projector four years ago and the thing has worked flawlessly from that time when he calibrated and tweaked it. Recently I have been having issues with slight sudden picture diming and image softening. This happens after the projector has been on a while and is preceded with a click noise but short of what a snap or tube arc would be. No error codes are displayed when this happens.

After removing the case I found the PA board was sagging in the middle like it was overheated. The board was so warped I had a heck of a time getting the thing out of the cage. The board seems to be fine from a visual inspection, i.e. no broken traces or melted components.

I removed the lenses suspecting a overheated tube caused by a glycol leak but all seems fine from that area.

Anyone ever see a sagging PA board in a G-70? Do you think the sagging board would have caused the dimming problem?.

**Curt Palme** · Posted: Sat Dec 26, 2009 4:46 pm Post subject:

Nope, probably not. Not unless the pix changes in focus and size at the same time (HV regulation). This sounds more like a video problem to me.

Matrix · Joined: 06 Sep 2006 Posts: 123 Location: Indianapolis, IN

Curt, long time since we have talked on the phone or posted to one another! Hope you have had time to rest during the Holidays but I see you are back at it already. I appreciate your advice so quickly.The video source is a Toshiba XA1 HD DVD player and a HD FuryII. My sons told me the same problem happens on the X-Box with a generic RGB to HDMI dongle . The signal passes through a 1271 switcher unit to the IFB-40. Maybe there is something in the switcher cable or the switcher it's self. I have removed the boards from the PJ and have cleaned everything up and now ready to re assemble. Plenty of dust inside!.

So you have never seen warped PA board?

ecrabb · Posted: Sat Dec 26, 2009 6:02 pm Post subject:

If there was enough heat to warp a fiberglass epoxy PCB, not only would the projector be non-functional, but there would have been components on the board itself that would have been torched. I think it would take something close to a full-on fire to warp a PCB.

The click noise you're hearing... Is it the same, or different from the click sound you hear when the projector changes resolutions? Does it happen right in the middle of a movie?

When the image goes soft/dim, what can you do to get it back to normal?

SC

**Curt Palme** · Posted: Sat Dec 26, 2009 6:09 pm Post subject:

No, I've never seen a warped board. See if you can get it to do it with the test patterns, that would eliminate all signal source devices.

Cheers!

CIR Engineering · Posted: Sat Dec 26, 2009 6:18 pm Post subject: Re: Sony G-70 Sagging PA Board

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

Matrix · Joined: 06 Sep 2006 Posts: 123 Location: Indianapolis, IN

I put all the boards back in and watched Aeonflux on HD DVD. The PJ seems to be stable at the moment. Aeonflux is a bit hard to diagnose with because the image goes from a warmer color temp to a cooler one as artistic license by the director. At least I think that is what it was and not the PJ this time around. All the tips above are appreciated and at this poinI am leaning toward a failing HV supply. The PJ will have to go awhile more before something happens where I can give more details of the symptoms during the anomaly. Stay tuned.

Matrix · Joined: 06 Sep 2006 Posts: 123 Location: Indianapolis, IN

One thing I forgot to mention.When I re-installed the sagging PA board I made a couple of plastic stand offs to support the midcdle outside edge of the board in the proper position within the cage. I believe one of the 3 HV connections was arching to the cage floor. With the board sagging like it was these three connectors were but a couple of millimeters from a ground source. About ten hours of use and the problem has not come back.

ecrabb · Posted: Thu Dec 31, 2009 12:58 am Post subject:

Excellent! Shade-tree engineering to the rescue!

I'd guess it wasn't that the board was warped, but that the board was installed improperly outside the guide rails (either at the factory or at some time later), and then under that constant pressure (and the heat from operation), essentially fixed the board in its warped position.

SC

**Curt Palme** · Posted: Thu Dec 31, 2009 1:27 am Post subject:

It's OK, We're all warped here to some degree, so your projector fits right in.

ecrabb · Posted: Thu Dec 31, 2009 4:01 am Post subject:

SC

**AnalogRocks** · Posted: Thu Dec 31, 2009 4:12 am Post subject:

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Matrix · Joined: 06 Sep 2006 Posts: 123 Location: Indianapolis, IN