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Old 11-15-2019, 10:58 PM   #27
gaijin4life
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Join Date: Mar 2014
City & State: California
My Country: USA
I'm a: Knowledge Seeker
Posts: 4
Default Re: Dell U2413 turning off

So replacing the two thyristors are the answer for this problem. Q971 and Q972. Unforunately the original MCR part had a non-standard arrangement of Gate, Anode, Cathode (K) leads, and there are none I could find with the correct order, so you MUST bend the pins to have the right one go to the correct hole on the board, changing the Littlefuse Thyristor from KGA pin order to GAK order to match the original part - you CANNOT use the default arrangement.

The replacement part you want is Littelfuse S4X8ES2, and mouser.com has them for a 45 cents each - the $7.99 shipping will be the most expensive part of this. I ordered 4 since they were so cheap so I had spares in case I accidentally broke a pin in the bending.

The data sheet for the part is here: https://www.mouser.com/datasheet/2/2...pdf-319336.pdf

To open the case on your Dell U2413, I highly recommend the ifixit kit with the guitar pick things (or actual guitar picks). They get the case open without marring it.

Iíve attached a few pictures showing where the parts are on the power supply board in the monitor and also how to bend the pins of the replacement thyristor so it has them in the correct order when you solder it onto the board. This will stick up a lot higher than the original due to the bending (so you donít have any of the legs touch - DO NOT HAVE THEM TOUCHING EACH OTHER AT ANY POINT), but thatís no problem.

Thank you Dell for cheaping out on parts, cutting another corner that your customers have to figure out to avoid throwing a perfectly good monitor away.
Attached Images
File Type: jpg q971.jpg (783.7 KB, 15 views)
File Type: jpg q972.jpg (563.5 KB, 14 views)
File Type: jpg thyristor.jpg (512.1 KB, 17 views)
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