HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

[scokljat]

Hello! :-)

I got this HP DV6 6170em laptop from a friend to repair it for myself or use it for parts. It's a nice looking laptop with 2GB ATI graphics and 2.3Ghz i5 dualcore CPU. I'm looking forward to repair it and use as my DJ-ing laptop. But...


Here are some initial facts:

1. user spilled some cola on the laptop. He immediately powered it off, disassembled (he did quite a lousy disassembling job, btw), he cleaned all cola residue and assembled the laptop

2. after cleaning he claims laptop worked and powered on few times for some time (15-30min), but than stopped responding

3. when power button is pressed power LED light up for a fraction of a second, fans spins just a little bit and than powers off. After about 5 seconds it powers on-off again and again in a loop every 5 seconds. (take look at a video)

4. when in on/off loop it does not responds to anything, not even to long press of power button. It always stays in a loop until battery is ejected.

5. no any picture on LCD, no backlite

6. when connected to AC adapter battery recharges OK, battery LED works.

7. same behavior on AC adapter and on battery.

8. nothing heats too much. In fact it runs quite cold.

9. PCB and components look OK, no corrosion or burned components. (take a look at pictures)


What I did so far:

1. disassembled the laptop completely step by step following service manual

2. removed everything removable from the motherboard (heatsinks, fan, RAM, CPU, CMOS battery, insulation)

3. thoroughly cleaned the motherboard with soap and warm water, than with demineralized water and finally with Kontakt WL spray (highly evaporate electronics cleaning solution) after thorough drying with hairdryer and compressed air

4. additionally cleaned CPU, RAM and all connectors

5. result - same as before


My questions:

1. what do you think, is there any chance for repair?
2. what should I try first? What to measure? Power supplies? Where? (I have 60Mhz oscilloscope, DVM, decent soldering station, reflow station...)
3. is there a chance CPU is dead? How to test it without a spare CPU?
4. can it be BIOS failure? (keep in mind it does not respond or switch off after long press to power switch...)

This is my video of the motherboard, powered on and in a loop:
http://youtu.be/nXX73IDOrv4

Attached are detailed pictures of the motherboard.


Any advice and help is more than welcome.

Thanks in advance,

Cheers!

Suad

[reaper57]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Try removing the yellow protective stickers on top of the gpu, chipset and cpu and clean the surfaces with isopropyl alkohol. If you have removed other plastic stickes from the board make sure that you aren't shorting something when installing the metal parts (heatsinks, keyboard etc.). If you have an ultrasonic bathtub that the board fits in try that. To clean the bga chips you can put some flux under them and reflow them, or reball them, or replace them if you have spares.

Otherwise, wait for someone with more knowledge on the circuitry and ICs on the board, to give you schemes and pinouts as I wasn't able to a lot of those online.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Try removing the yellow protective stickers on top of the gpu, chipset and cpu and clean the surfaces with isopropyl alkohol. If you have removed other plastic stickes from the board make sure that you aren't shorting something when installing the metal parts (heatsinks, keyboard etc.). If you have an ultrasonic bathtub that the board fits in try that. To clean the bga chips you can put some flux under them and reflow them, or reball them, or replace them if you have spares.

Otherwise, wait for someone with more knowledge on the circuitry and ICs on the board, to give you schemes and pinouts as I wasn't able to a lot of those online.

I removed yellow protective stickers from chipset and GPU, but not from CPU, actually it really looks clean. I removed all other plastic stickers from the motherboard so I can wash it in detail and I test the motherboard out from the laptop casing so nothing can be shorted (look at the video).

I don't have ultrasonic bathtub. Reflow will be my last try after I check everything else.

There are refurbished motherboards from china at ebay, but after I spend some serious money I would really try to fix original motherboard and somhow test the CPU.

Thanks,

S

[hazardus]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

First check PL13 for 5V and PL17 for 3.3V.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

First check PL13 for 5V and PL17 for 3.3V.

Hazardus, thank you for starting precise diagnostic procedure. But, there are only 12 PL's at upper side of the board named PL801 - PL812. PL808 is unpopulated. Look at the attached picture.

Which PL's did you refer to? You probably looked at wrong schematics.

This motherboard model umber is - 650800-001

Thank you!

Cheers,

Suad

[ktmmotocross]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

check all coils

[reaper57]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Yeah I should have mentioned that you should try a reflow only as a last resort. Sorry about that.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

check all coils

I checked all coils when laptop is on battery. Some voltages are consistent, some voltages are missing and some voltages shows briefly and insufficient at the moment when power LED flashes and fan spins a little bit, repeats in a 5sec. loop.

Results:

PL801 - 0V
PL802 - 0V
PL803 - 0V
PL804 - 5.24V
PL805 - 0V - 0.6V - 0V - 0.6V... (shows 0.6V briefly in the moment when power LED and fan briefly come to life - repeats in a 5sec. loop)
PL806 - 3.33V
PL807 - 0V
PL808 - not installed
PL809 - 0V
PL810 - 0V - 0.7V - 0V - 0.7V... (shows 0.7V briefly in the moment when power LED and fan briefly come to life - repeats in a 5sec. loop)
PL811 - 12.5V
PL812 - 0V - 1.6V - 0V - 1.6V... (shows 1.6V briefly in the moment when power LED and fan briefly come to life - repeats in a 5sec. loop)
L - 815 - 0v - 0.9V - 0V - 0.9V... (shows 0.9V briefly in the moment when power LED and fan briefly come to life - repeats in a 5sec. loop)


Look at all readings on the attached picture.

So, it looks to me like it retries to power up but something is missing or shorted... but nothing gets hot as I see.

What do you think? What to do next?

Looks like we are making some progress, right? ;-)

Thanks!!!

Cheers,

Suad

[hazardus]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

I don't have the right schematic for this board that's why I wrote the wrong numbers. If you have the correct schematic share it so we can help you. Tomorrow if I'll have some time I'll try to find a schematic for your board.

[hazardus]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Looks like you have 5V and 3.3V too. So that's good.
Next step remove the CPU and check resistance to ground on PL807 PL809 PL801 PL803 and PL802.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Looks like you have 5V and 3.3V too. So that's good.
Next step remove the CPU and check resistance to ground on PL807 PL809 PL801 PL803 and PL802.

Harazdus, I don't have schematics, I would gladly share it if I have it.

Thank you very much for quick response and your effort to help me :-)

Here are measurements to ground (CPU removed):

PL807 - open
PL809 - open
PL801 - 9.5ohm
PL803 - 9.5ohm
PL802 - open

PL810 - 39ohm
PL812 - 0.92Kohm
PL805 - open


PL801 & PL803 9.5ohm?! hmm...

Cheers!

S

[hazardus]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

PL801 and PL803 looks really low. We need to find a schematic before we are making conclusions. I'm really busy today and tomorrow.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Schematics, please! Anyone?

Motherboard and laptop details:

Motherboard spare part number: 650800-001 - System board for use only with computer models equipped with an Intel dual core processor and the Intel HD6770 graphics subsystem with 2048-MB of discrete memory

Laptop model: HP DV6 6170em with Intel SR04B (Intel Core i5-2410M) CPU 2.3Ghz dualcore

Thanks,

S

[reaper57]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

I didn't find any schematics, but it turns out I have the same laptop (almost).
At first when I read i5 and a 6770 I didn't even think about it now, but now I checked and it turns out that I have the same laptop, with the difference that mine has an amd phenom cpu and a 6650 gpu.
If the power delivery is the same I can help you by taking some readings on my board. Just tell me what to test and I'll do it when I have some free time.

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

I didn't find any schematics, but it turns out I have the same laptop (almost).
At first when I read i5 and a 6770 I didn't even think about it now, but now I checked and it turns out that I have the same laptop, with the difference that mine has an amd phenom cpu and a 6650 gpu.
If the power delivery is the same I can help you by taking some readings on my board. Just tell me what to test and I'll do it when I have some free time.

Reaper, thank you for your help.

It would be great if you can test the following (assuming two motherboards have same components):

Check the pictures.

Do all resistance measurements with CPU and memory removed.

1. resistance between 1 and 2 (important)
2. resistance between 3 and 4 (important)
3. resistance between 5 and 6
4. resistance between 7 and 8
5. resistance between 9 and 10
6. resistance between 11 and 12
7. resistance between 1,2,3,4,5,6,7,8,9,10,11,12 to ground


First two measurements are most important, don't bother with the rest if you don't have enough free time.

Thank you very much!

Best regards,

Suad

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

No ideas? Anybody? I really hate to quit...

Cheers,

Suad

[reaper57]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

No ideas? Anybody? I really hate to quit...

Cheers,

Suad

Don't give up on it! I finally got time to do the resistance measurements.
Sorry about taking such a long time I was really busy with school and work and didn't have enough time disassemble my whole laptop.
Anyway I finally did it... but there is a problem... I forgot the file with the measurements on the computer at work.
I'll try to post them tomorrow afternoon.

[dellxps15]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

best working method is to know where it was spilled the cola . what zone... if it goes near lvds connector , kb controller, cpu, video and so on. look where it was the cola for shorted pins or blown resistor -capacitors.

i had a hp i3 with spilled liquid and there was a short in the lvds socket on mainboard. cleaned all and resoldered back pins and is working fine now.

[Topher_UK]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Might be an obvious question, but could the power switch have cola residue in it, causing a short? It would maybe cause an on/off cycle - once switched on, if you hold the power button for 5 seconds it would switch off, so if it's cycling off after 5 seconds, it's a possibility. It's happened to me before now. If the power button has a seperate board, maybe give that a clean?

[scokljat]

Re: HP DV6 6170em - motherboard dead after liquid (cola) spill. Please help!

Don't give up on it! I finally got time to do the resistance measurements.
Sorry about taking such a long time I was really busy with school and work and didn't have enough time disassemble my whole laptop.
Anyway I finally did it... but there is a problem... I forgot the file with the measurements on the computer at work.
I'll try to post them tomorrow afternoon.

Thank you Reaper, looking forward to your measurements :-)

Cheers!

S