CurtPalme.com Home Theater Forum

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

A friend of mine has a Sony 1251 projector, he bought it a half year ago from ebay, since however it was said as perfect machine but there is a problem is some horizontal problem. The problem is intermittent, sometimes it come up right after turning on, sometimes after 10-20mins of use, sometimes it goes away. Turning off and back on usually solves the problem for a couple of minutes. The input is fed from Y/Pb/Pr and RGBHV via IFB-12. When the picture is shaking then the test patterns not always shaking.
I have checked all yoke connections, searched for soldering errors on the top two boards, disassembled the LVPS but I haven't found anything.
Oh and a video from the issue: link
Any idea?

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

The problem is still unsolved.. I did some testing, and the problem isn't in the H def. board. The internal test patterns mostly seems to be stable. But driving from input A or video doesn't matters, if it is shaking it is shaking from both input. It looks like the problem is that the sync signal is not timed correctly to the signal, because at 480i I can get a stable picture while driven with PC mostly alwalys present a very minor shaking, if it is worsening then it is visible with the video signal too. If I am correct the sync signal passes BB, BA, Y boards, but which one is the sinner?

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Pull it down and put up an NEC, that will fix this issue. Wink

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

Probably, but 1. it's not mine, 2. it is too good shape to scrap out, 3. at the moment there is no crt projector on the market which would come close to this in performance...

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

It was only a joke bud Wink

HK-Steve · Posted: Thu Feb 02, 2012 9:25 am Post subject:

I have a similar issue with my Marquee,
Hopefully someone can help out.

Cheers

opv · Joined: 18 May 2010 Posts: 202 Location: Emek Hefer,Israel

Are you sure the problem isn't source related?

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

Yes, we tried over component cable, I have a video test pattern generator, and tried with RGBHV, and the problem was present with all source, the video input looks much more stable than RGB, however it also shakes sometimes. For example at 1024*768@60Hz the shaking is always noticeable (>1cm on a 2m wide screen) here the internal test patterns are shaking this much too. With 800*600@90Hz it looks more stable, the shaking is not that much noticeable (but still is!) the internal patterns are stable. Same for 640*480@100Hz

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

An other problem(?):
This sony has IFB-12 input card, it was configured as YPbPr, and did the reverse of the "proggressive scan enable" procedure, but now I getting very dim picure from RGBHV, I mean from video source I get the same brightness at cont: 40 brt: 50 while RGB needs cont: max, brt: 50. Did I something wrong?

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

Hello,

I think you know that the IFB12 was never intended to be used with the 12XX series. Sure it was and is done, but the IFB12 is higher evolved as you know and can cause more problems. Have you tried to reset all dip switches, or do you have a IFB11 or IFB10 card for tests? Have you tested to change sync polarity on a PC with Powerstrip? Or you could try to use a 1270/1271m switcher with a ccqbrs cable. I have old Sony here that does not make a picture over the IFB ports, so I was forced to get a 1271 switcher plus ccqbrs cable to get it running. Was the last idea to save a old CRT, but so far it works.....
About the dim picture: When you go through the Menus with the page button, have you changed the option from Auto to Clamp or vice versa? (cant remember the name exactly).
Good luck