DLP4500: Brightness changes

Yoni Sher

Part Number: DLP4500

Hi,

My DLP4500 lightcrafter has recently started exhibiting an 8% brightness fluctuation with a 1 minute cycle, which appears as a square wave when measured by a photo-diode used to calibrate my system. I have tested every part of the system separately and concluded that the DLP is the cause, but I can't find any troubleshooting guide for this problem nor think of any reason it could occur.

The Input is via the mini-HDMI cable, using 1140x912@60 resolution.

Is there a factory reset option for the DLP4500 (and would that help)? what other options can I try?

Yoni

over 7 years ago

0 Saad Idrees over 7 years ago

Prodigy 140 points

Hi Yoni,

I once had a problem which might be similar to this one. I noticed change in brightness whenever I would step to a different rgb level. For example, if my input is a grey image with rgb 30 and I switch the input image to rgb 60, the first frame after this switch has a much lower brightness than the frames following. I think the LED(s) got a bit slower. So I now use it in pattern sequence mode where I keep LEDs on all the time. Not sure if thats the best way but maybe it would help you as a temporary solution (unless you are already working in pattern mode).

Best,

Saad

0 Yoni Sher over 7 years ago in reply to Saad Idrees

Prodigy 150 points

Hi Saad,

Thanks, but I'm using an external pulsed laser to illuminate the DMD which I also tested separately and showed no issues. The strangest part is that this happens even with a fixed pattern on the DMD.

Yoni

0 Sanjeev over 7 years ago in reply to Yoni Sher

TI__Mastermind 30875 points

Hi Yoni,
Are you using the pattern mode or video mode? You mentioned about the fixed pattern is it still image or still pattern displayed in the pattern mode?
Regards,
Sanjeev

0 Yoni Sher over 7 years ago in reply to Sanjeev

Prodigy 150 points

Hi,
I'm not sure - I plugged in an HDMI cable and I display on the "second screen" in full screen mode. The "fixed pattern" is that I'm playing a "video" with only one frame in it for about 5 minutes.
Yoni

0 Sanjeev over 7 years ago in reply to Yoni Sher

TI__Mastermind 30875 points

Hi Yoni,
First configure it in Video Mode via GUI, then see the video, if it looks choppy as before, this can be problem with the video timing.
Regards,
Sanjeev

0 Yoni Sher over 7 years ago in reply to Sanjeev

Prodigy 150 points

Hi,

This appears to have solved it. I will keep you posted.

Thanks,

Yoni

0 Sanjeev over 7 years ago in reply to Yoni Sher

TI__Mastermind 30875 points

Hi Yoni,
Thanks for confirming.
Regards,
Sanjeev

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DLP4500: Brightness changes