Strange ghost Circles after DMD chip and Lamp Replacement - AVS | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 
Thread Tools
post #1 of 9 Old 08-26-2014, 11:25 PM - Thread Starter
Member
 
InstantEulogy's Avatar
 
Join Date: Jan 2006
Posts: 137
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 14
Strange ghost Circles after DMD chip and Lamp Replacement

Hi Guys,

I recently replaced the DMD chip and put in a new Philips bulb and new Mitsubishi housing as well. I replaced the lamp because it was dim, and the DMD board because I had white dots on my screen. The white dots are gone and the screen is bright (had to turn brightness down to 22 from 30's before), but now when the screen is displaying a dark or black image, I can see about 6 grayish (ghostly almost faded) solid circles (almost perfect looking circles), all of them about the width of a coke can, and they all have different brightnesses slightly.

I own a 2009 73 inch 73737 Mitsubishi set. I cleaned it out well with a vacuum when I did the work. I also made sure there was no dust on the projector lens and cleaned it carefully with lens tissue. I didn't touch the surface or glass on the DMD chip, it looked really clean...so I skipped the shopjimmy step of wiping it off with a micro fiber cloth.

I really don't want to keep moving this huge screen around to take it apart, so I'd like to be as efficient as possible this time fixing it.

I'll try and take a picture of the problem later. But they are literally about the size of a coke can ring, and not just a grey ring, but filled in as well.
InstantEulogy is offline  
Sponsored Links
Advertisement
 
post #2 of 9 Old 08-28-2014, 09:26 AM
Member
 
marcusb84's Avatar
 
Join Date: Apr 2008
Posts: 46
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 10
I had a similar thing happen to Samsung DLP. It's dust on the DMD.
marcusb84 is offline  
post #3 of 9 Old 08-30-2014, 02:19 PM - Thread Starter
Member
 
InstantEulogy's Avatar
 
Join Date: Jan 2006
Posts: 137
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 14
That sucks that a brand new DMD chip has crap all over it right out of the package. Swwweeeetttt quality control!
InstantEulogy is offline  
post #4 of 9 Old 08-30-2014, 06:03 PM
AVS Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Posts: 3,108
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 239 Post(s)
Liked: 162
Also, turn your brightness back up to around 30 and turn your contrast control down in order to control the brightness of the picture (brightness actually controls the black level while contrast controls the white level).
Augerhandle is offline  
post #5 of 9 Old 09-03-2014, 06:47 AM
Member
 
marcusb84's Avatar
 
Join Date: Apr 2008
Posts: 46
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 10
Quote:
Originally Posted by Augerhandle View Post
Also, turn your brightness back up to around 30 and turn your contrast control down in order to control the brightness of the picture (brightness actually controls the black level while contrast controls the white level).
There is a way to clean it I'm pretty sure. Other's reported similar problems like I said. My TV is the HL61A750 and I know I read about cleaning the DMD to get rid of these.
marcusb84 is offline  
post #6 of 9 Old 09-05-2014, 08:38 AM
AVS Special Member
 
Augerhandle's Avatar
 
Join Date: Jan 2009
Posts: 3,108
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 239 Post(s)
Liked: 162
Quote:
Originally Posted by marcusb84 View Post
There is a way to clean it I'm pretty sure. Other's reported similar problems like I said. My TV is the HL61A750 and I know I read about cleaning the DMD to get rid of these.

To be clear, my post was a pointer about his television settings in his OP, and not a reply to the DMD chip dust spot issue.

Last edited by Augerhandle; 09-05-2014 at 08:46 AM.
Augerhandle is offline  
post #7 of 9 Old 09-07-2014, 03:33 PM - Thread Starter
Member
 
InstantEulogy's Avatar
 
Join Date: Jan 2006
Posts: 137
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 14
I still haven't gotten around to cleaning off the chip yet. I'm hoping to pull the TV out tonight to work on it. As far as the brightness and contrast settings, I started out with the recommended settings for my monitor on this forum after a few people had it professionally calibrated. Then, to match my viewing environment I used the DVE calibration blu ray and a THX blu ray calibration disc to set black levels and brightness. Even when I hit the power button and the lamp and screen take about 2 minutes to shut down, I can still see the ghost circles until the TV completely turns off after about 2 minutes.

Important question though: Should I use some 91% alcohol or something in addition to wiping off the glass surface of the DMD chip?
InstantEulogy is offline  
post #8 of 9 Old 09-11-2014, 09:33 AM
Member
 
marcusb84's Avatar
 
Join Date: Apr 2008
Posts: 46
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 10
Quote:
Originally Posted by Augerhandle View Post
To be clear, my post was a pointer about his television settings in his OP, and not a reply to the DMD chip dust spot issue.
I'm sorry, I meant to reply to his post and not yours
marcusb84 is offline  
post #9 of 9 Old 10-11-2014, 10:10 AM - Thread Starter
Member
 
InstantEulogy's Avatar
 
Join Date: Jan 2006
Posts: 137
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Liked: 14
I will post back here when I get the chance to clean off the DMD as that is my next step. I've been lazy since I replaced the DMD and lamp to want to pull out the TV again and take it apart.
InstantEulogy is offline  
Sponsored Links
Advertisement
 
Reply Rear Projection Units

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off