CurtPalme.com Home Theater Forum

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

Hi All,

I have a slight YA board problem.
Yesterday when I turned on the G90 all the menus
seem not to synch properly. I'm not sure if synch is the right
word, I can bearly see the menus, they are wavy, and move around slightly.

Though control of menu items is fine. Contrast brightness etc..all respond good.

In terms of the picture (i.e. watching movies), it is displaying
perfectly and I do not have any issues changing contrast or brightness
etc (only thing is that when pressing contrast it is readable...but very unstable).
So I can still watch movies on it with any problems!

I will try to post a picture of this.

I thought of changing IC502, IC503 (SRAM), not sure if that would make
a difference. IC501 seems a likely culprit...but I don't think this
is available.

I changed YA boards with a good board, and the problem dissapears,
so I think the issue is somewhere in the YA board, and not related to the
BA board (OSD insert IC).

If anyone has any ideas or pointers, or if there is a known fix for this, that really would
be great.

Thank you!

Shaz

JohnHWman · Posted: Mon Oct 03, 2011 2:30 pm Post subject:

Hi Shaz,

It looks like an issue with the OSD clocking system (frequency unstable) or the PLL that sync the OSD to the displayed image (either source or internal OSC). Is this OSD problem is there with G90 internal oscillator (with no projector inputs) ?

I don't think that it is relevant to OSD SRAM unless you see incomplete characters on the screen.

Later

John

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

Hi John!

Many thanks for your reply.
This occurs even with out any input connected,
the characters are OK, so
I guess not the SRAM then....

The test patterns are stable (I think these are generated via IC571 -- I will check this again
with pictures), but the menu items are very unstable.

I will get a picture today or tomorrow, just away from the PJ at the moment.

John, do u think it could be the PLL circuit, IC601, IC602 -- these are available,
and I ordered them today, and thought I might change these and see if it
fixes the problem. I hope it's not IC501.....

Thanks!

Shaz

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

Possible failing cap around ic571, ic551 or ic501.

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

thank you for the response.
I will take a look @ the board tomorrow.
Thanks!

Shaz

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

I've attached some pictures, for further clarification.
Test patterns are stable, but menu text moves across to the side, on off...picture is upside down,
because I did not change polarity (please ignore that).

Shaz

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

One more thing, waviness in test pattern is due to projecting on a blind (temporary)

thank u!

Shaz

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

Mac,
On visual inspection the caps look OK around ic571, ic551 or ic501.
But I will change them.
If that doesn't work, next will be the PLL circuit, IC601, IC602....

Shaz

CIR Engineering · Posted: Sun Oct 09, 2011 11:41 am Post subject:

I am very busy right now, but if you don't have this resolved when I get free in a week or so I will try and help too. But you are in good hands already Smile

Also, with YA boards you can always send them to me for repair if you run out of ideas (and I think John may sometimes take them on as well).

craigr

shaz782 · Joined: 21 Dec 2006 Posts: 45 Location: US

thank u very much Craig!
I'm going to change the caps this week, then
the PLL circuit....if that doesn't fix it, then
I'll send to u to take a look!

thank u!

Shaz

bobcollins12 · Joined: 25 Sep 2013 Posts: 8 Location: San Diego, CA

I'm having a similar problem with a G90. All else is OK but the all the menu characters are jittery / unstable...moving slightly to the left and then back. Seeems like some kind of horizontal sync problem or clock timing...? I know this has been a while ago, but what did you end up doing to fix.
Thanks,
Bob

**Curt Palme** · Posted: Wed Sep 25, 2013 12:31 pm Post subject:

This sounds more like a sync signal over a bad YA board. A bad YA board shakes the picture violently. I had one with a bad RGB input board that did this, or the sync settings in the menu may not be ideal for your source. If your sync and clamp settings in the service menu are set to 'auto', try setting them to something other than 'auto.

if you disconnect the input completely, are the internal menus stable?

bobcollins12 · Joined: 25 Sep 2013 Posts: 8 Location: San Diego, CA

Thanks for the really good suggestions. I'll try them and get back to you. It'll take a day or so. Have relatively limited time to do some of this stuff - other jobs, wife, etc. - but I am a little befuddled and would like to know what's going on. As far as I know it just happened...fine when I shut down one day and jittery the next time powered up.
There is no violent picture shaking. The PJ functions other than the menu characters being jittery are perfectly fine. And the menus are not unreadable - just not stable. They all work like they're supposed to also. Be back soon.
Bob

bobcollins12 · Joined: 25 Sep 2013 Posts: 8 Location: San Diego, CA

Had a little time to experiment some. I just wrote the following:
Everything is perfectly stable with no input. I tried changing sync settings, etc. Didn't affect anything. The real problem might be that it could be intermittent. Makes diagnosis a little more difficult. I've checked 3 days in a row and it seems to have gone away just as strangely as it showed up. Will be back if the problem re-appears. Fingers crossed.
Then went to recheck before submitting...
and the problem has returned. Tried the same things again that you suggested. No effect. Clamp changes have no effect. Back on H/C. Sync changes - no effect. Back on Auto.
I've been talking with Craigr about this and a few other things. He says he's seen it before and can fix - something to do with the YA board, I believe he said. Open to more suggestions if you have any. Otherwise I think I'll wait for awhile and see if it could actually just go away, as unlikely as that may be.
I'm about to change out the Dallas Chip. Do you think it could have anything to do with that chip? I've had the PJ since 2003.
9/30 - Left Projector on and watched a recorded football game. Menu was stable with no problems after game. Could not duplicate problem. Will check again today.
Bob