Identify chip toshiba C55t

[Mazorca]

I have a toshiba C55t-C5300, motherboard model DABLQMB16B0 rev:B. No luck finding the schematic. This chip, marked PU4 consumes around 200 mA when 5v are put in with the bench power supply. Lower voltages do not turn it on. It heats up rather quickly. Markings appear to be 3G=2G and U25 underneath. It has 5 contacts on each side, total of 20. One appears to have a balled up solder joint. No power, no lights at all. DC jack ok.
Further research indicates that DA0BLQMB6E0 is similar board. Quanta BLQ.
Help please identifying it.

[JaroTech]

Re: Identify chip toshiba C55t

Richtek RT6575AGQW Dual-Channel Synchronous DC/DC Step-Down Controller with 5V/3.3V LDOs

[meritosari]

Re: Identify chip toshiba C55t

[Mazorca]

Re: Identify chip toshiba C55t

Thank you so much both of you. I had an idea that it was a voltage regulator but no idea who made it. Forever in debt.

[JorgeCaceres]

Re: Identify chip toshiba C55t

anybody knows what PU5 is in the DA0BLQMB6E0 REV:E Board? its marking says R068 5318. Help please.

[Mazorca]

Re: Identify chip toshiba C55t

anybody knows what PU5 is in the DA0BLQMB6E0 REV:E Board? its marking says R068 5318. Help please.

I looked up at my board, I see no useful markings on it.
Voltages are, starting with the corner dot, (not necessarily pin1) counterclockwise direction
1 GND
2 0v
3 2.20v
4 1.08v
5 0v
6 and 7 GND
8 0.58v
9 GND
10 GND
11 GND
12 0v
13 and 14 GND
My board is faulty, bad PU4, but I still get Vin, from voltage divider down from 19v to 4.7v, and starts to consume (gets hot). I see no Vin on my PU5. Test for Vin on yours.

[meritosari]

Re: Identify chip toshiba C55t

anybody knows what PU5 is in the DA0BLQMB6E0 REV:E Board? its marking says R068 5318. Help please.

I think its GMT-G5318

https://cdn.badcaps-static.com/pdfs/...aff4a27a7e.pdf

[JorgeCaceres]

Re: Identify chip toshiba C55t

I looked up at my board, I see no useful markings on it.
Voltages are, starting with the corner dot, (not necessarily pin1) counterclockwise direction
1 GND
2 0v
3 2.20v
4 1.08v
5 0v
6 and 7 GND
8 0.58v
9 GND
10 GND
11 GND
12 0v
13 and 14 GND
My board is faulty, bad PU4, but I still get Vin, from voltage divider down from 19v to 4.7v, and starts to consume (gets hot). I see no Vin on my PU5. Test for Vin on yours.

i have no vin at all, in the power jack i get unstable power, (not even close to 19 v), i have short everywhere, i track it at hp8s36 mosfet that is controlled by PU7, (PU7 has a hole in it, i manage to identify it), then i saw PU5 (also with a hole in it), I'll order the GTM ic Meritosari is talking about. I hope that's all that has blown on this board. haha. Thank you man, i'll post as soon as i have news.

[JorgeCaceres]

Re: Identify chip toshiba C55t

I think its GMT-G5318

https://cdn.badcaps-static.com/pdfs/...aff4a27a7e.pdf

thank you bro! i'll try that one and post here any news. Thank you all.

[JorgeCaceres]

Re: Identify chip toshiba C55t

Hi guys, Here is the thing, i tracked down all the shorts on this board, ( three mosfets, PU4, PU2, PU5, and PU7 where shorted to ground), i finally get my 19v in the input, but, PU7 is doind something weird, pin9 is shorted to ground, i lifted PU7 and the short still there, removed the ceramic cap, and still there, my question is, this means i have a dead processor or an internal short (between two layers in pcb)?, both will be impossible to fix i guess.

PD: should i put this on a new thread?

[LatinMcG]

Re: Identify chip toshiba C55t

Hi guys, Here is the thing, i tracked down all the shorts on this board, ( three mosfets, PU4, PU2, PU5, and PU7 where shorted to ground), i finally get my 19v in the input, but, PU7 is doind something weird, pin9 is shorted to ground, i lifted PU7 and the short still there, removed the ceramic cap, and still there, my question is, this means i have a dead processor or an internal short (between two layers in pcb)?, both will be impossible to fix i guess.

PD: should i put this on a new thread?

test with ohm.. if its 8-14 ohm its normal for cpu.

[rmaero]

Re: Identify chip toshiba C55t

Hi! I had the same IC as the OP heating up (same board, but from a Toshiba S55) would it be safe to try to power the board without that chip? since it's a 5V/3.3V regulator it will not boot I'm guessing...
anyone have schematics for this board?

[piernov]

Re: Identify chip toshiba C55t

Never safe to power a board with the buck controller removed. Nothing to pull down the gate of the MOSFETs of the buck converter so they can get triggered randomly.