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Honor Student
Posts: 2
Member Since: ‎06-22-2010
Message 1 of 15 (24,423 Views)

Hp 6735b won't boot


I've got a hp 6735b that won't boot, the caps and numbers LED flashes 5 times and nothing happens ----out of warranty of course; anyone with suggestions how to get it going?


Thank you!

0 Kudos
Posts: 10,924
Member Since: ‎01-31-2009
Message 2 of 15 (24,391 Views)

Re: Hp 6735b won't boot


Check below document:

HP Notebook PCs - Blank Screen LED Error Codes

** Say thanks by clicking the "Thumb up" icon below. **

** Make it easier for other people to find solutions, by marking my answer with "Accept as Solution" if it solves your issue. **
Honor Student
Posts: 2
Member Since: ‎06-22-2010
Message 3 of 15 (24,383 Views)

Re: Hp 6735b won't boot

Thank you! That link was most helpful.

Best regards,


Honor Student
Posts: 2
Member Since: ‎03-22-2011
Message 4 of 15 (23,567 Views)

Re: Hp 6735b won't boot

Even I have Compaq 6735b. I am undergoing the same problem and I really need help...

History - 

I am using the Compaq 6735b over 2 years with a warranty of 3 years. During waranty period the motherboard was changed once because it became a failure due to excessive use of graphic card - ATI radeon 8000 with  a Graphic Memory of 1gb exactly. Moreover when i used to switch on the laptop, the fan or what used to give out very high power and speed vibration with sound (don't know the exact term for this problem). Fullscreen applications and movies always used to run as smooth as possbile but later when i used to open them, the laptop used to trip and automatically shut down without notice. I then adjusted for minimal performance and maximum battery save in ATI radeon option. For some weeks, it ran smoothly but as you know minimum performance. Suddenly even then it started to trip over. The thing is everytime it tripped, the laptop used to get very hot and the fan used to suddenly tun extemely fast with extreme power and speed. I gave it to HP for repair. It took about 3-4 weeks for the HP people to repair it by adjusting the new motherboard. 

Every thing ran fine and as great as possible for 3-4 days. It was awesome experience to use ATI then. But again the same problem came but this time the process was quite slow. Motherboard did not break off that easily. Over long time, the condition became worse. I couldn't even switch on laptop since it used to get tripped even during startup probably when it used to become very hot. I used to store it in Regrigerator (in deep freeze) and then used to try out by cleaning the laptop with a vacuum cleaner at high power so that even the minimum dust particles go away and increase air ventilation. Yeah it worked! But only for 2 hours. I played GTA IV (PC GAME) with highest possible graphics and so after 2 hours again TriP!!... MY bad luck. I then turned over to Windows vista. You must be thinking how since the laptop used to trip during startup. I did it using refrigerator. Kept it at install with full battery in refrigerator and thatr's how i installed WIndows Vista. I downloaded the BIOS package from HP official server for downlaods of drivers and softwares and hardwares and installed it. It asked ofr restart and I did and this was the outcome:

1.Black screen (No Display/probably LCD switched off)

2.No booting

3.LCDs(CapsLock and Numlock) did blink 5 times in rhythm (depicing System Board Failure)

4.Strange but rythemic sound came from DVD-ROM

5.Volume on/off and wireless LCD touch screen buttons over keyboard did not respond.

6.In front of laptop, 4 LCDs (within small glasses) are there for wireless , battery/adapter , disk usage(includes CPU usage and harddisk /rom usage) ,  and Power. The disk usage LCD also blinked in rhythm.


I thoguht at first that Hard Disk is not connected properly. I opened the harddisk chamber and found the system board conenctor for harddisk was broken with pins apart. Tried to adjust it but no Laptop did not boot. 

I gave it to HP for repair but at first they did not accept but later they did since there was a contract between my company and theirs.

After 5 monthS!!!!!! they gave it and said we can'[t repair it!. But i was the one helpless. At about 12 midnight after doing all my work, I oepned the hard disk chamber and saw that system board connector was ok this time. Amazingly i saw that harddisk wasn't attached to the connector. I myself attached it however with soem force probably the connector was too big or not well adjusted in the small hard disk chamber. What a glory and a miracle!!! The laptop did open and at first it showed that BIOS recovery is done. Opened perfectly. I then upgraded the BIOS from the HP official website. and then restarted. It did not open. Laptop remained in the old irritating condition



Honor Student
Posts: 2
Member Since: ‎03-22-2011
Message 5 of 15 (23,566 Views)

Re: Hp 6735b won't boot

today a miracle happened again... the condition was same - same hang on boot with black screen and 5x blinking of LCD... now i got very angry... i pressed all the buttons on laptop keyboard and waited for 2-3 minutes... suddenly the fan started to run with high speed and guess waht... the system started and it booted and windows started..... unfortunately i forgot to recover bios... what shall i do// i am very scared... now if i close who knows if it again opens or not...

options -

1. reboot and see the effect. if opens normal no problem. if not then try the same procedure.

2. install another bios from hp which ought to work and then reboot but scared of the early 2 results due to bios upgrades.

3. never close laptop which is impossible for IT worker...

DECISSION PENDING... ... ... ... ...






Posts: 1
Member Since: ‎04-29-2011
Message 6 of 15 (23,202 Views)

Re: Hp 6735b won't boot



I have the same exact problem, 

i pressed the keyboard and the laptop powered back up.


Have you since replaced your motherboard?

How have you resolved the problem?



Honor Student
Posts: 2
Member Since: ‎05-06-2011
Message 7 of 15 (23,084 Views)

Re: Hp 6735b won't boot

I have the exact problem problem. Ordered a new mother board from China and it has the same fault. I'm waiting now what the dealer has to say about it ...


Nice ...

Honor Student
Posts: 3
Member Since: ‎05-26-2011
Message 8 of 15 (22,845 Views)

Re: Hp 6735b won't boot

I'd posted about this in the hardware thread.  I'm having the exact same issue.  Black-screen, LEDs x5.


I've replaced the system board (received the same error), and then the processor (still the same error).  I've tried every solution I've found on the Web no matter how ridiculous: all to no avail.


I would love to hear insight from anyone.

Honor Student
Posts: 1
Member Since: ‎06-16-2011
Message 9 of 15 (22,680 Views)

Re: Hp 6735b won't boot

I am a laptop repair technician and now I'm repairing a 6735s with the same problem. I reached this forum seeking information on the 5 flashes the caps lock.
After removing the computer's motherboard I found that pressing hard on AMD SB700 Southbridge, the computer turns on and shows the hp logo on the screen. The solution is reballing this chip. It is an advanced repair and is not available to everyone, because it requires specialized training and equipment.

Honor Student
Posts: 3
Member Since: ‎05-26-2011
Message 10 of 15 (22,624 Views)

Re: Hp 6735b won't boot

That's interesting, but as I've replaced both system board and CPU, I don't think that's my issue.  Or if it is, there must be another component that's blowing the chipset at power-up (or all these chipsets exhibit this behaviour fequently).


...holy crap.


As I'm typing this, I have my laptop in front of me, keyboard removed and heatsink loose on the CPU.  I pressed down on the heatsink above where the chipset is located and I'll be damned if this PoS didn't boot after a few moments.


Unfortunately, my HDD is out.  I'll have to shut down and see if I can get this hog running again.


Great tip, Kwisatz!  Reball the chipset?  Yeah, I'll whip out my soldering iron and a magnifying glass.  What could possibly go wrong!  Seriously, though, I have no idea how I'd even find some one with the equipment and skill to do this.

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