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Old 11-08-2014, 10:05 AM   #21
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Ok I found PQ42!! It was on the other side of the board a little underneath the heatsink. Its a SI4800BDY. I tested other ones as well (PQ53 and PQ58), and they all show 600 ohms from 1 to 5, and open from 5 to 1. I'll try replacing PQ41 only unless there other opinions? Any significance in the markings for FDS6690AS? PQ41 has PKFXF?, and PQ59 and PA54 have AKFBT
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Old 11-10-2014, 06:06 AM   #22
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

I think the problem is pq41. Try replacing it and post the results.
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Old 11-10-2014, 08:21 AM   #23
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Thanks reaper. I ordered the part on ebay. Let you guys know as soon I replace it.
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Old 11-29-2014, 01:52 PM   #24
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Thanks reaper for your help. I changed the part (pq41) and now the laptop seems to work well in my limited testing. No shutdown so far. The part still gets hot to the touch. I guess that's normal since there is a lot of current going through it? I may try to put a small heatsink on it to guard against another failure.
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Old 11-29-2014, 02:32 PM   #25
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

hot? not bad. maybe some short.
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Old 11-30-2014, 08:39 AM   #26
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

If it's not hot as in burning-your-finger hot, it's okay.
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Old 11-30-2014, 12:08 PM   #27
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

If I keep it on for a few seconds it stings. It's been working for a few days now so I think I'm good to go for now. Next issue is the crashed hard disk
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Old 12-09-2014, 05:42 AM   #28
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

MOSFETs are ok with running a bit hot. They're not like bga chips. Bgas usually damage the solder after a year or two if they run at over 70-80C for long periods of time. MOSFETs are more resistant to heat. If you can keep your finger on it for a few seconds it's probably under 65-70C.
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Old 12-21-2014, 10:09 PM   #29
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Still running well! Thanks to all who helped, especially reaper. #1 forum !!
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Old 06-02-2021, 04:13 PM   #30
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Hi all,
Jumpstarting an old thread, as my laptop finally bit the dust. This time it no longer boots into bios. I took it apart again and verified that the same chip (PQ41) I replaced had gone bad again. This time, however, it took out a capacitor with it (PC27) 10 microfarads 25VDC, and actually took about 1/3 of it and scorched it up!

Any advice on how to replace the SMD capacitor? Do you think it may have caused irreparable damage?

The laptop for the last year exhibited the same old symptoms of sometimes failing to boot, but once powered on it would work correctly.

Angelo
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Old 06-02-2021, 07:26 PM   #31
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

>> Any advice on how to replace the SMD capacitor? Do you think it may have caused irreparable damage?
From the looks of it, there's a short circuit between +VIN (19V) and GND at the area, you can measure resistance across PC29 below

You may remove the cap PC27 with no adverse effect on the board, and clean up the burnt area
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Old 06-04-2021, 04:29 PM   #32
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Hi there is a small crater where one of the pads should be. The pad seems to be lifted. I think I may be able to connect the capacitor there, but it may be difficult. I checked the resistance between the good pad and the lifted pad and measured about 586 ohms one way, and open the other way. Also, across pc29, I measured 586 ohms one way, and open the other way. Seems like there is no short correct? I removed pq41 and when I measure across 1 and 5 of the pcb pads, I get 235 oms one way and 185 ohms the other. Attached is a picture of the "cleaned up" area
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Old 06-14-2021, 07:54 PM   #33
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

>Hi there is a small crater where one of the pads should be. The pad seems to be lifted. I think I may be able to connect the capacitor there, but it may be difficult.
Hi, sorry for the delay
No need to reinstall the cap for now, the board should work without PC27 attached, as it's on the +19V line (there are several capacitors in parallel on that line)

My suggestion is to cut the lifted trace with a X-acto/hobby knife, clean with alcohol, then you can use "UV Solder Mask", or nail polish to cover the burnt area
Please see attached picture, as a suggestion where to cut the lifted trace
cut-trace.jpg
If you wish to reinstall the cap (after the board is working), you can scrape a bit of the green solder mask on the good part of that trace and solder the cap there

Please post pictures of the other side of the burnt area

> I checked the resistance between the good pad and the lifted pad and measured about 586 ohms one way, and open the other way. Also, across pc29, I measured 586 ohms one way, and open the other way. Seems like there is no short correct?
PC29 is in parallel to PC27, that's why you get the same readings. i suggested to measure there for convenience, so yes, looks like there's no short on the +19V line


> I removed pq41 and when I measure across 1 and 5 of the pcb pads, I get 235 oms one way and 185 ohms the other.
From the schematics at post #10 https://badcaps.net/forum/showpost.p...5&postcount=10 it's a 1.2V line, low ohms value is normal for a low voltage line, your values look fine (PQ41 is the low side MOSFET), the values may vary depending if CPU is installed or not when taking measurements

Please replace PQ41 before connecting power to the board, otherwise you will get 19V on the 1.2V line and cause damage to the board and CPU

Also, measure in diode mode across PQ42, you should get the same readings as before (red probe on 5 and black probe on 1 should read open; black probe on 5 and red probe on 1: around 500-600)

Maybe someone has other suggestions, feel free to comment
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Old 06-16-2021, 06:36 AM   #34
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Hi Thanks you for the advice. Attached is the other side of the burnt area where pq42 is. It seems fine? I measured PQ42 and it shows 580 ohms one way, and then open the other as before.
For cutting the pad, I think I can solder the cap there without any issue by placing it slightly diagonally and butting against the lifted pad. Do you think I should still cut it? I see you circled an area on pq41. Should I put nail polish there too?
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Old 06-16-2021, 06:40 PM   #35
m1ch43lzm
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

>Hi Thanks you for the advice. Attached is the other side of the burnt area where pq42 is. It seems fine? I measured PQ42 and it shows 580 ohms one way, and then open the other as before.
Yes, it looks fine, PQ42 is not shorted

>For cutting the pad, I think I can solder the cap there without any issue by placing it slightly diagonally and butting against the lifted pad. Do you think I should still cut it?

May be possible, just make sure the lifted pad doesn't move and possibly touch an inner copper layer of the board (that's why I suggested to cut the lifted trace), in that case you should cover the underside of the lifted trace with nail polish first, let it dry completely before attempting to solder the cap.

But first, replace PQ41 before testing, as I explained before, without PC27 attached
If the board works fine, then you can deal with installing a new cap later
For testing just connect screen, power button, and the DC jack, and test with USB keyboard/mouse

>I see you circled an area on pq41. Should I put nail polish there too?
To me it looks like exposed copper, I can't tell from the picture
Better cover the exposed copper with a tiny bit of nail polish, just to be safe, before replacing PQ41
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Old 06-17-2021, 04:50 AM   #36
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

ok thank you. This is very helpful. As soon as I receive the parts I will let you know.
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Old 06-19-2021, 03:48 PM   #37
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

I think I messed up big time. I was trying to remove some solder from the pads because it was a little bumpy but ended up smudging two pads together. I am unable to remove the solder with the solder wick. I tried multiple times.

It looks like pins 2 and 3 are on the same pad from the schematic? So maybe its not an issue?
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Last edited by lmcancu; 06-19-2021 at 03:57 PM.. Reason: clarifying
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Old 06-20-2021, 03:23 PM   #38
m1ch43lzm
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

>I was trying to remove some solder from the pads because it was a little bumpy but ended up smudging two pads together
tt's not an issue, pins 1-2-3 are connected together, same from pins 5-6-7-8, pin 4 is isolated and should not have continuity to the other pins

> I am unable to remove the solder with the solder wick. I tried multiple times.
Doing so will make it look uglier, as you will be scratching the (green) solder mask more and leaving more bare copper exposed, and solder will stick to it; the purpose of the solder mask is to avoid solder sticking to copper
As long as it's soldered properly, even if pins 1-2-3 look bridged, should be fine
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Old 06-24-2021, 05:04 AM   #39
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Quote:
Originally Posted by lmcancu View Post
(PQ41) I replaced had gone bad again. This time, however, it took out a capacitor with it (PC27) 10 microfarads 25VDC, and actually took about 1/3 of i
Can i ask a question ? i've a lot of capacitors on donner boards (not working.. i can't measure voltage .. just capacity with a multimeter) ..
BUT... how i can determine the voltage?
if i place 19V on a 6.3V cap it burns?
or i need an high frequency voltage to be sure to uderstand if the cap is a 6.3 or a 25V ?
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Old 07-09-2021, 11:43 AM   #40
lmcancu
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Default Re: HP DV6-2064CA will only power up if its off for about 5 to 10 minutes

Hi I purchased a new motherboard instead of fixing this one. This one always gave me issues. I suspect the capacitor got fried due to a short to some part of the laptop frame. Part of the frame is in contact near the capacitor and only separated by a thin layer of insulation. Suspect this is what caused the failure
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