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  • TI Thinks Resolved

DLPLCR4500EVM: Horizontal lines in projected picture

Prodigy 50 points

Replies: 10

Views: 281

Part Number: DLPLCR4500EVM

Hello,

when projecting a picture sequence there are serveral horizontal lines in the middle of the picture, which have information from the following pattern in it (pictures from buffer swap). Doing firmware updates, changing pictures, mixing the sequence or resetting the board doesn't fix the problem. But connecting a different light engine to the evaluation board fixes the problem. The two pictures below are showing the horizontal line. For your information we used a different projection optic.

Is this a known problem of the light engine? Can we fix it without sending it for repair? If not is it possible to get a new light engine ?

Kind Regards

  • Hello Pascal,

    Could you please clarify if this light engine has always had this problem or if it's a new development? Is this the same light engine as the default EVM one?


    Thanks,
    Kyle

  • Hi Pascal, 

    Do these lines appear in every when displaying solid patterns? When you swapped the light engine, did you use the same DMD as the original engine? Did these lines appear out of the box? Was the EVM dropped?

    These questions will help us determine if the issue resides with the DMD or the components inside the light engine.

    Thanks, 

    Brandon

  • In reply to Kyle Rakos:

    Hello Kyle,

    the light engine is the same as the default EVM one. We only changed the projection lens. After some tests we found out that this error occurs randomly. Sometimes, when the sequence is called repeatedly, the horizontal lines disappear for one sequence, but then they reappear in the following sequences.

    Thanks for your fast response,

    Pascal

  • In reply to Brandon Seiser:

    Hey Brandon,

    This lines appear randomly. If a sequence is projected repeatedly, the error can occur in the first sequence and then disappear or reappear in the following one. We have swapped patterns and tried others, but this error can occur at any time. Sometimes a pattern is projected correctly and then the next time it is projected incorrectly. Also when starting the projector in video mode the default lightcrafter pictures provided has these lines. We didn't swap the light engine, we only changed the projected lens for smaller focus length. In the beginning we hadn't this issue. The EVM wasn't dropped.

    Thanks for your fast response,

    Pascal

  • In reply to Pascal Kern:

    Hi Pascal, 

    It seems from the reported symptoms that some of the lines going to the DMD may be having a connection problem, which explains the sectors with previous patterns. Some of the lines are getting connected intermittently, which causes the problem to go away in some frames. Can you try disconnect and reconnect the DMD flex cable to ensure it is tightly connected or try replacing with another flex?

    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hey Hirak,

    we checked the flex cable after your message. Both connectors (to the board and to the DMD) are without damage. Furthermore they are firmly connected. Should we still replace the flex cable? Is it possible to replace the light engine without the corresponding board?

    Thank you and best regards,

    Pascal

  • In reply to Pascal Kern:

    Hi Pascal, 

    Are you using the TI EVM light engine or you manufactured on your own?

    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hi Hirak,

    we are using the original TI EVM light engine. We only removed the projections lens.

    Best Regards

    Pascal

  • In reply to Pascal Kern:

    Hi Pascal, 

    The problem seems to be a little weird. Can you kindly reevaluate again if it is really related to the removal of Light Engine Lens? When you say "connecting a different light engine solves the problem" what do you mean by that? How is the light engine different from the one with which you reproduced the problem?

    Thanks & Regards,

    Hirak.

  • In reply to Hirak Biswas:

    Hi Pascal, 

    Do you still need the answer to your question? I'll be temporarily closing this thread due to inactivity, you can reopen anytime. 

    Thanks & Regards,

    Hirak.

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