Note on archived topics.

This topic has been archived. Information and links in this thread may no longer be available or relevant.
If you have a question create a new topic by clicking here and select the appropriate board.
maggie-o Tutor
Tutor
9 0 1
Message 21 of 35
13,309
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Hi there- Still trying to get my C700 Laptop to charge/power on?  My AC adapter is putting out the right power, and I got that DC adapter and plugged it into the bottom, but still no blue charge light.  Any help would be appreciated.

Thanks - Maggie

0 Kudos
vamp Top Student
Top Student
3 0 2
Message 22 of 35
13,014
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

I had the same proble on a C700. I was able to find the problem. The problem was that PQ1 was bad. Is located next to the PCN1 "where the power jack connects to the motherboard next to the memory". PQ1 is a P-Channel PowerTrench MOSFET P#: FDS6675BZ. I replaced it and the problem was solved.

maggie-o Tutor
Tutor
9 0 1
Message 23 of 35
13,011
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Hi there!  Thanks so much for this information! How did you replace that part?  Does it clip on or did you have to solder it?  Also, any particular place that you got it?  Thanks again - maggie

{Personal Information Removed}

0 Kudos
vamp Top Student
Top Student
3 0 2
Message 24 of 35
12,992
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

The FDS6675BZ is soldered to the board. It has to be removed and solder a new one. You can find it online. onlinecomponents.com  has it in stock, is about $0.85.

myccsonline Honor Student
Honor Student
1 0 1
Message 25 of 35
12,794
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

I know this is getting to be an old post, but I had this issue and it was the chip you pointed out .  Thanks for that!  I have a dv-7 with a very similar issue it dosnt charge but the light on the connector(dc Jack light) says its getting power as long as the battery is in and charged up.  If you remove the battery the light goes out. and no power  to the unit.  Ive tried known good battery and power cords no different.  I took unit apart and couldnt see any failed parts, power passes through the connector to the board ok.  Do you know if there is a control chip like this on a dv-7?  Any input would be great.. 

John-1960 Honor Student
Honor Student
2 0 0
Message 26 of 35
12,775
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Having the same problems as every one else how do you fix this problem. No power and have bought a new charger.

0 Kudos
susanfixit Student
Student
1 0 0
Message 27 of 35
12,311
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Did you ever fix the power problem ? I am having the same trouble , Did you use any reference material?

0 Kudos
Joe-B Student
Student
1 0 0
Message 28 of 35
12,045
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Tired of laptops that quit and the "solution" is a new $1000,000 system board, or to most people, a new laptop, after trying the obvious, I opened up my daughter's C700.  Wondering how you found the problem, I assumed that you did PC work and was used to surface mount repair (yuck!).

 

After hunting around, I found the schematic, found PQ1, and checked voltages.  Gee, it was nice to have info to finally be able to do something but look at a dead motherboard!

 

Oh oh, PQ1 has voltage on the other side.  OK, not my issue.  After some frustrating time, analyzing what I'm looking at, trying to find test points, places to do any sort of checks, I went back to this area.  Hmmm.. no voltage out of PQ2.  Looked at its control, hit it with gnd/B+ - still nothing...hmm.. OK, well, dead board, not like I could cost any more, right?  I shorted input to output.  Plugged in the battery (something that I could try to check voltages on - yeah, desperate - HA!), and fan was attached for an indicator.

 

The battery on this hadn't charged for quite a while, I was told.  But now the blue light came on.  OK, something...  Plugged power switch back in, hit it and the fan went on.  Really?  What a long shot.

 

Yep, that brought the PC back from the dead and a bonus, the battery would now charge.  I didn't have more time to play, have to drive 6 hrs back home soon.  Went out and had to buy a soldering iron - (couldn't get solder from sears because when we brought it to the counter, it was all recalled??? Geesh). Anyway, finally soldered a pin bent into a U shape from input to output on PQ2.

 

I have no idea what this circuit does - I expected maybe the power light to stay on when the battery was in and I unplugged it - or something as bad or worse.  I haven't seen any downside.  I think my daughter said it wasn't showing that the AC was attached (in the tray).  I didn't go farther to figure it out - it seems to do more than before - it would now even charge the battery besides back to fully functioning.  Only issue that she didn't care about, was that the stupid plug for the speakers disintegrated instead of coming out.  She didn't want me to bother to solder them in.

 

So, thanks for pushing me to dig around to find the schematics and push on to actually fix the PC with the cost of a soldering iron and solder (the pin was free), instead of an industry mandated dead laptop!

0 Kudos
pvr726 Honor Student
Honor Student
4 0 0
Message 29 of 35
11,935
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

Joe

 

Thanks a lot for the update.

 

I primarily bought the C700 3 years back based on a low cost based selection for $400 and subsequently replaced the keyboard and A/C charger once. Now its not powering on and I am sure the problem is not the cord. The only option seems to be to repair it myself - there is no way I'm going to spend $300 on a new mother board or someone else to repair it.


@Joe-B wrote:

Tired of laptops that quit and the "solution" is a new $1000,000 system board, or to most people, a new laptop, after trying the obvious, I opened up my daughter's C700.  Wondering how you found the problem, I assumed that you did PC work and was used to surface mount repair (yuck!).

 

After hunting around, I found the schematic, found PQ1, and checked voltages.  Gee, it was nice to have info to finally be able to do something but look at a dead motherboard!

 

Oh oh, PQ1 has voltage on the other side.  OK, not my issue.  After some frustrating time, analyzing what I'm looking at, trying to find test points, places to do any sort of checks, I went back to this area.  Hmmm.. no voltage out of PQ2.  Looked at its control, hit it with gnd/B+ - still nothing...hmm.. OK, well, dead board, not like I could cost any more, right?  I shorted input to output.  Plugged in the battery (something that I could try to check voltages on - yeah, desperate - HA!), and fan was attached for an indicator.

 

The battery on this hadn't charged for quite a while, I was told.  But now the blue light came on.  OK, something...  Plugged power switch back in, hit it and the fan went on.  Really?  What a long shot.

 

Yep, that brought the PC back from the dead and a bonus, the battery would now charge.  I didn't have more time to play, have to drive 6 hrs back home soon.  Went out and had to buy a soldering iron - (couldn't get solder from sears because when we brought it to the counter, it was all recalled??? Geesh). Anyway, finally soldered a pin bent into a U shape from input to output on PQ2.

 

I have no idea what this circuit does - I expected maybe the power light to stay on when the battery was in and I unplugged it - or something as bad or worse.  I haven't seen any downside.  I think my daughter said it wasn't showing that the AC was attached (in the tray).  I didn't go farther to figure it out - it seems to do more than before - it would now even charge the battery besides back to fully functioning.  Only issue that she didn't care about, was that the stupid plug for the speakers disintegrated instead of coming out.  She didn't want me to bother to solder them in.

 

So, thanks for pushing me to dig around to find the schematics and push on to actually fix the PC with the cost of a soldering iron and solder (the pin was free), instead of an industry mandated dead laptop!


 

 

Where did you find the diagrams and what kind of skills does it take to solder and unsolder MOSFETs on mother board?

 

 

0 Kudos
daseed22 Student
Student
1 0 0
Message 30 of 35
11,872
Flag Post
HP Recommended

HP compaq Presario C700 LAPTOP NO Power

thanks bro!!! thats the solution!!! im from uk so it was hard to find FDS6675BZ - FINALY I BOUGHT IT FROM E-BAY (CHINA) the pprice was 7£! so - I DON'T HAVE SOLDERING IRON AND I BRAKE THE "LEGS" OF FDS6675BZ THAN I "SOLDER" THE NEW ONE WITH MELTED PEACE OF PLASTIC!!! sounds funny but now im typing this massage from my compaq c700!!! your the man!!!

0 Kudos

Note on archived topics.

This topic has been archived. Information and links in this thread may no longer be available or relevant.
If you have a question create a new topic by clicking here and select the appropriate board.
† The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation