Fixing defective DLP DMD chip?

I've changed a couple of hundred in Mitsubishi and Samsung rear projectors, and the DMD chips were Texas Instruments.

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.

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 :-#)#

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?

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:

Thanks for taking the time to respond!

John :-#)#

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:

or in tinyURL speak:

John :-#)#

Mouser has 47 of these DLP650LEFYL DMD chips left in stock @ $153USD. Damn. Should have bought from them!

John :-#(#

John :-#)#

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.

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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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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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.

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mal pad they were originally equipped with.

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.

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.

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 :-#)#

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.

Thanks for the note, yes, that was what I did, just a large drop in the middle then compress evenly.

John :-#)#