Hello everyone, this is my first post here
... Also, English is not my native language so sorry for any strange sentences or words
I got my hands on a barely used Epson TW650 projector for 1000CZK, which is around 40USD (what an absolute steal
) at a local marketplace - the catch being that it does not turn on. it was being used by some local interior design company for some semi-art installation type of thing. It was sent to a local Epson service center and they diagnosed the board as being faulty. Instead of paying for a out-of-warranty repair they decided to upgrade to a TW-750 which is largely the same thing (very similar or the same light engine) but it has miracast so they can share photos and videos from phones through it (an upgrade definitely
NOT worth the 800$ price tag IMHO, but at least i got a free almost-working projector
) I did some some quick math and figured that even after replacing the board with a new one it would be still cheaper than buying a (well) used functioning one.
While doing some online research (aka Googling) i noticed three things: a)
Epson has a completely different lineup of projectors in north america and Europe it seems Epson US and Europe actually shares models, they just have different names, the TW650 is Home Cinema 1060 in the US, b) There is next to none technical documentation, repair guides or anything of that type for the European models and c) Not turning on seems to be a common fault of the TW-650. Since im going to poke around this beast anyway why not post my findings online and maybe help others (or get some help from the more experienced users around here
).
First of all, i made some Hi-Res pictures of the mainboard with my Panasonic DC-S1, hopefully it will be of use to someone:
I also stumbled upon this
iFixit post and it seems the main culprit behind these projectors not turning on is a faulty voltage regulagtor chip made by Texas Instruments, the
TPS55435-2A. Here it is on the board (marked by a red dot):
Actually, there are 5 of them on the board. The line between two sides of a capacitor indicate where the short circuit can be measured. The users on iFixit reported it heating up with 12v power on (i guess both the high and low side switches shorted) but on my board only the output and ground is shorted - it seems only the low side switch is K.O., there is no heating up and the only way to "see" the short is by measuring it. At least i hope it is the regulator that is shorting, it seems to be providing the 1.8V line to the main projector SOC (big chip near it) and if that one is toast this board is junk since i have no access to BGA rework equipement
. I also searched for obvious bad caps but all seem to be fine. The projector does indeed look almost unused from the inside so i am betting more on the problem being of the "random" nature (such as a faulty voltage regulator) than a stress or age related issue like a bad cap somewhere. Searching on the TI forums revealed this chip is the revision of the TPS55435 which had problems with low and high side mosfets going bad (
source) so i took the leap of faith and ordered replacement chips from Mouser (ETA: 11/10/2021). When the chips arrive and i get my hands on a hot air rework station (since i moved to a different city to study on a university i no longer have the space to store such items
) i will follow up with an update.
If anyone here has access to or knows how to access a datasheet for the SOC or schematics of this board sharing would be greatly appriciated
UPDATE1:Many thanks to the user fzabkar for providing
this link. Whats the most interesting is the fact that the US marketed Home Cinema 1060 and Europe marketed TW650 share the same motherboard (they are the same projector, basically, with a different name). After a little digging i found
this iFixit post confirming the TPS55435 being a common fault theory.
UPDATE2:Indeed, the marked chip, labeled IC3000 was faulty. After the replacement the projector immediately came back to life. The pad under the chip is grounded and connected to a large ground pane i suspect one layer down in the PCB. Use a sufficiently powerful soldering iron and heatgun or you will get into problems as i did (I managed to accidentaly tear off the NC pad).
I have one more chip left so if you are in europe and need one, PM me and i can sell you the leftover one 
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