Brother, i Have problem with dell 3421 no power issue. Its 5v, 3v ok. I have flashed bios. but no power. SIO power 3.3v and VCC POR 3.3v ok. But Sio not release Rsm_RST. So dont know whats wrong. can any body point out this problem.
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Last edited by nazrul145; 11-01-2014, 07:11 AM. -
Re: Dell 3421, No Power.....
your RSMRST from southbridge that goes to SIO chip so if its missing then do a reflow or change the chip.
typical DELL come on
Just cook it! It's already broken. -
Re: Dell 3421, No Power.....
Thanks, but i already reflow southbridge. is rsmrst# goes to sio to southbridge? or southbridge to sio chip.Comment
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Re: Dell 3421, No Power.....
sio to southbridge
Check SIOComment
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Re: Dell 3421, No Power.....
Do you have all the conditions prior to RSMRST met?Attached FilesComment
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Re: Dell 3421, No Power.....
Thanks everybody speacially Khaahk. I have noticed that 5v_s5 and 3.3v_s5 is not present in U3601 AND U3602. But I have a same working Motherboard this board also 5v_s5 n 3d3_s5 is not preset without power button press. But this schematic indicate 5v_s5 and 3.3v_s5 must be ok befor rsm_rst#. I dont know what happend.Comment
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Re: Dell 3421, No Power.....
Both powered from adapter?Comment
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Re: Dell 3421, No Power.....
No, i used bench power supply. Both from power supply, also use adapter. The ok motherboard RSMRST# is ok but faulty motherboard rsmrst not present.Comment
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Re: Dell 3421, No Power.....
It beeps 3x..Comment
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Re: Dell 3421, No Power.....
do a reflow!Just cook it! It's already broken.Comment
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Re: Dell 3421, No Power.....
Hi bro I was googling around to get the schematic of this board, and I finally
could get it on this thread.
So what happens is I got this notebook, and as soon as I plug the dc adapter the PSU light goes off. So there's a short somewhere. some guys form chip level repair told me to go straight to the VCC core section and lift all fets and check them I did that, and fets were fine.
Then I focused myself on the VIN section I lifted all fets and they were fine.
any ideas how I should go on, I'm thinking on 3v 5v always regulator and fets.
But I'm starting to think maybe the SIO could be shorted.
can you give me some ideas. Thanks. I have a lab supply to inject voltage if needed.Comment
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Re: Dell 3421, No Power.....
check power on rst,then scl and sda with cro if not change I/osigpicComment
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Just cook it! It's already broken.Comment
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Re: Dell 3421, No Power.....
turning this old thread live again to know the solution for 3 beeps error.
and also PL4401 is grounded.
Looks like PU4201 is dead, will replace it and let you know but what was the earlier fix.Last edited by dspok; 09-05-2015, 10:57 PM.Comment
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Re: Dell 3421, No Power.....
inject psu to short to see burning componentComment
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Re: Dell 3421, No Power.....
Thanks for update schematicComment
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Re: Dell 3421, No Power.....
My personal experience is PM_PWRBTN# signal is lost and I just reflow the chipset and the laptop can switch on. Thank's for sharing the schematicComment
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Re: Dell 3421, No Power.....
Thx for fileComment
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