Fixing defective DLP DMD chip?

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I've ordered a replacement display chip for our 2013 Benq MW519  
projector and I see that the youtube folks say this Digital Mirror  
Display can't be serviced.

So, being the contrary kind of person I am, I figure - well maybe it can?

Thus the question - has anyone here played with one of these and if so,  
any success what so ever? Our display has (so far) 3 bad mirrors roughly  
near the middle of the screen so somewhat annoying. I figure when I have  
the replacement (eBay, used, there don't seem to be any new available)  
in hand then I might be willing to experiment on the sick unit. Unlikely  
that I can save it, but who knows?

Time will come to break out the binocular microscope and see what is  
going on...

John :-#)#

Re: Fixing defective DLP DMD chip?
On Sunday, September 8, 2019 at 6:15:37 PM UTC-4, John Robertson wrote:
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I've changed a couple of hundred in Mitsubishi and Samsung rear projectors, and the DMD chips were Texas Instruments.

https://cdn.shopify.com/s/files/1/0189/1890/files/4719-001997_1910-6143W_DLP_Chip_ee98eb65-0def-4d08-94d1-a7bb58da1051.jpg?v15%24157252

From what the engineers told me, the mirror pivots fracture over time leaving some mirrors stuck open and some stuck closed (light and dark spots).

I had previously tried heating, cooling, and g-shocking the chips, but there was never any change.

I would never use a used DMD unless the customer is informed the replacement may very well start spitting out stars in mere months.

Re: Fixing defective DLP DMD chip?
On 2019/09/08 6:41 p.m., John-Del wrote:
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I am the end-user of the used DMD, I don't have a part number for the  
original and so ended up buying a used one. I agree it won't be as  
reliable as new, but without the part number I was hooped. And we are  
losing one pixel a day now.

Are these still available as new or NOS?

Thanks,

John :-#)#

Re: Fixing defective DLP DMD chip?
On Monday, September 9, 2019 at 1:52:10 AM UTC-4, John Robertson wrote:
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The ones for the Mitsu and Samsung (same part number) were as recently as 3 months ago when I got one from Mitsu, but supposedly TI is either eliminating production or already has.  Does the one you need look like the one in the link I posted?

Re: Fixing defective DLP DMD chip?
On 2019/09/09 6:37 a.m., John-Del wrote:
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I have not pulled out my original. I am waiting for the replacement  
before shutting down our home projector... According to the photo on  
eBay (yeah...!) it does not look like that. This was what I ordered:

https://www.ebay.com/itm/223202086282

Thanks for taking the time to respond!

John :-#)#

Re: Fixing defective DLP DMD chip?
On 2019/09/09 6:37 a.m., John-Del wrote:
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TI at least still lists it. I should have thought of searching on TI's  
site before as I think this is the DMD I am looking for:

http://www.ti.com/dlp-chip/display-and-projection/standard-chipsets/products.html?pqs=paqs&familyid35%54#p2841max=WXGA%20(1280x800)&p1907=DMD&p191312%80x800

or in tinyURL speak:

https://tinyurl.com/TI-DMD

John :-#)#

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Re: Fixing defective DLP DMD chip?
On 2019/09/09 6:37 a.m., John-Del wrote:
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Mouser has 47 of these DLP650LEFYL DMD chips left in stock @ $153USD.  
Damn. Should have bought from them!

John :-#(#

John :-#)#

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Re: Fixing defective DLP DMD chip?
On Monday, September 9, 2019 at 11:25:19 AM UTC-4, John Robertson wrote:
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One of my buddies had a contract with a city near us to maintain their projectors, and they changed TONs of those.  If you're planning to keep the projector for a few more years, I suggest buying one of the remaining new DMD chips.


Re: Fixing defective DLP DMD chip?
On 2019/09/09 9:43 a.m., John-Del wrote:
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Hi John,

What do you recommend for the heatsink compound/film for the DMD chip?

Also the face of this new chip (from Mouser) appears to be dusty, they  
simply packed the chip without any plastic wrapping in an antistat.com  
foam box. Is there any way to clean it or do I take this up with Mouser?

Thanks!

John :-#)#

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Re: Fixing defective DLP DMD chip?
On 2019/09/11 2:09 p.m., John Robertson wrote:
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Looking closer I see that there is a clear window, I assume I can clean  
that using similar practices used on camera lens...

So, just what does it need for the heatsink junction is my question. I  
don't trust youtubers that much.

John ;-#)#

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Re: Fixing defective DLP DMD chip?
On Wednesday, September 11, 2019 at 5:14:18 PM UTC-4, John Robertson wrote:
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The DMD chips supplied by Mitsu and Samsung included the same thin thermal  
pad they were originally equipped with.

The few that I swapped from donors I used Dow 340 (my favorite heat sink co
mpound).  You certainly can use Arctic Silver or other similar compound.  I
 don't think that chip gets particularly hot in any case.

The front window is uncoated glass, and you can use anything on it to clean
 it.

I'm concerned with the dust though..  Mouser has always been a good supplie
r but I wonder if the DMD chip you got isn't a used one.  Before installing
 it, look at it under a strong eye loop while slowly rotating it.  Any stuc
k pixels will stand out.

Re: Fixing defective DLP DMD chip?
On 2019/09/12 7:05 a.m., John-Del wrote:
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mal pad they were originally equipped with.
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k compound).  You certainly can use Arctic Silver or other similar compou
nd.  I don't think that chip gets particularly hot in any case.
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lean it.
plier but I wonder if the DMD chip you got isn't a used one.  Before inst
alling it, look at it under a strong eye loop while slowly rotating it.  
Any stuck pixels will stand out.
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The dust blew off...and no stuck pixels.

The replacement TI chip worked just fine, and I used thermal paste  
instead of a thermal pad. I did check that the chip was under some  
compression against the heat sink prior to using the compound, and we  
polished the contact face of the heatsink hoping to get a slightly  
better heat transfer. I assume (hope) that was a good idea...

Ran it last night for five hours...

Thanks for the advice!

John :-#)#


Re: Fixing defective DLP DMD chip?
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ished the contact face of the heatsink hoping to get a >slightly better hea
t transfer. I assume (hope) that was a good >idea..

Another thing about heatsink compound, otherwise known as birdshit is you d
o not spread it. You put it at the center of the pressure and squeeze it, t
his does not make air pockets. Air pockets defeat the whole purpose, enough
 of them you might as well put it on dry, or maybe lick it.  

When I fix the high power shit it stays fixed.

Re: Fixing defective DLP DMD chip?
On 2019/09/17 8:03 p.m., Jeff Urban wrote:
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Thanks for the note, yes, that was what I did, just a large drop in the  
middle then compress evenly.

John :-#)#

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