CurtPalme.com Home Theater Forum

CIR Engineering · Posted: Tue Oct 04, 2016 2:20 pm Post subject:

Also feel free to ask me any questions about calibrating the G90 via PM. There are menus beyond the service mode, a hidden gamma menu...

craigr

ElTopo · Joined: 07 Nov 2006 Posts: 1640

Does the G90 still beat the present digitals ? Mr. Green

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

Well, got a leaker! Got to redo the silicone job.

Honestly I'm surprised that the tube doesn't get pried out of that thin little silicone bead by the weight of the magnetics, given that
there is no silicone backfill or any other method of tube retention in the frame aside from the silicone functioning as an adhesive.

Edit: Silicone job redone. Used more this time. When I pried it apart I could see where the leak was, due to NOT ENOUGH SILICONE.

CIR Engineering · Posted: Tue Oct 04, 2016 7:41 pm Post subject:

You did use old fashioned silicone 1 right? Not silicone II. Silicone II is too soft.

craigr

CIR Engineering · Posted: Tue Oct 04, 2016 7:44 pm Post subject:

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

I'm using a couple different types of Dow Corning silicone products. The stuff I'm using for the G90 tube installation has good stiffness, very much like what was in the frame after first removing the tube. I used substantially more this time, too.

I haven't gotten around to removing the red lens yet but the green tube will certainly be replaced. It's rather worn, and interestingly, has what looks like a big spot burn in it, but down low on the tube face about the middle.

CIR Engineering · Posted: Tue Oct 04, 2016 8:11 pm Post subject:

About the silicone:
In a pinch, you can get clear silicone 1 from most Home Depot stores. It really works just fine. I however usually mail order black silicone 1. The GE black silicone 1 is 077027003123.

About the burn:
If there is a burn spot I would hold off on putting good tubes in the set. This usually results from an error on the YA board. This can result from several causes, but I can always repair error 88's. I have a 100% success rate on this repair (and yes it involves a lot of surface mount work). To test for now, leave the projector plugged in and in standby. Wait...... if you get a solid orange or red error 88 on the alphanumeric while the projector is idling or running you have this problem. If it happens while the projector is running you will most likely burn your tubes.

It's frustrating because sometimes this error will come up regularly and is easy to spot. But with some cases it's like a time bomb because it may go months without throwing an 88. Then one day you either come down when the projector is off and see the 88 and know to get it fixed, or you are very unfortunate and it trips while running and you toast your tubes.

Watch out for this. The 88 88 when booting up is normal, but 88's any other time is bad.

craigr

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

Good to know.

I'm just running the original two tubes, R and G, plus an imperfect blue that won't make me cry if it gets burned, for test purposes.

It's due for a new Dallas chip which I've ordered, and I'll check the YA board. Is there anything specific I need to know about, well, anything, that I could advise you of by looking at the right parts?

CIR Engineering · Posted: Tue Oct 04, 2016 10:07 pm Post subject:

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

I guess I need to figure out where to find that and how to get it out of the projector. I'll check the manual.

**Curt Palme** · Posted: Tue Oct 04, 2016 10:31 pm Post subject:

Back right corner of the Ya board.

CIR Engineering · Posted: Tue Oct 04, 2016 10:36 pm Post subject:

IC421 is on the YA board. The YA board is the equivalent of a CLM in the Marquee. The alphanumeric display board at the back of the G90 is plugged into the YA board. To get the YA board out just remove the grey cover with the black thumb screws. Disconnect the wire harness for the composite and s-video. and pull the grey cover away.

The YA and BA boards are behind that cover (the BA board is like the VIM on a Marquee). You will notice black tabs at the end of both those boards. Put a thumb under the two black tabs for the YA board and pull the tabs back (they rotate and pry the board out). This will eject the YA board.

You will see the giant Dallas chip. IC421 is located between the Dallas chip and multi-pin connector.

craigr

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

SONY
CXD305
-127R
003A01E

So Sayeth The Chip!

CIR Engineering · Posted: Tue Oct 04, 2016 10:54 pm Post subject:

Yeah that's the sh*tty lot Sad

It may never fail, and it might fail tomorrow. But if it goes there is no replacement.

Take heart in the fact that I service about 85 G90's and many are still purring along with that lot number. Many have also failed and a new YA was installed.

Best of luck!

craigr

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

Gee, thanks, Sony!

So it's a crapshoot.

What I'll do is use some thermally conductive adhesive and glue a heat sink to that chip. If it runs cooler, it'll be less likely to fail.

Oh well, you take your chances in life.

Wasn't there some investigation made into a replacement/substitute for that chip? Something using an Atmel FPGA?

**Curt Palme** · Posted: Tue Oct 04, 2016 11:28 pm Post subject:

There's a really long thread here somewhere. I called it 'a call to arms', and it went on for pages and pages. It's not the chip running hot, it's one production run. Someone here seemed to think that the substrate was manufactured poorly, and the D/A chip starts to oscillate. They all fail the same way, the data output runs wild, and all parameters of the set are all over the map. Then you get a focus or convergence error eventually as the settings cause an overcurrent situation on the output board, and the Ya board shuts the set down.

CIR Engineering · Posted: Tue Oct 04, 2016 11:38 pm Post subject:

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

It'd sure be nice to have a friendly Sony engineer who could sneak out the source code for that chip's programming,
and then I could have a friend of mine make up some Atmel processors that are work-alikes for it.

Actually since Sony is totally out of the business of making or supporting CRT projectors, if you could contact the RIGHT people
at Sony, they might actually release the code to you.

CIR Engineering · Posted: Wed Oct 05, 2016 12:56 am Post subject:

Read the thread, we've been through that Wink

craigr

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

All right, here's a little more information.

The "spot burn" is not really a spot burn, it's a wear mark on the lower center tube face (as seen with the lenses off and the PJ on the bench in front of you, sitting on its feet) and it's present on all three tubes. Well, both red and green. the blue tube being physically broken, there was no phosphor still adhered in that area so I can't tell.

It's not a burn through the phosphor, it just looks like beam extinction happened there, several hundred or thousand times.

Is that normal for a G90?

This projector came to me with P19LQF series tubes.

The amount of wear on the tubes is high for a 2000 hour set. I'd estimate 8000 hours based on tube wear.