HP 6735b - no post and Caps Lock, Num Lock blinking 5 times

[Nicker321]

hmm...I used a replacement power supply, with exactly the same votage and power, of course it also has the suitable connector with the center pin.

Do you think there is too much noise or rippling in the voltage of this power supply?

I can measure exactly 19VDC and it`s strong enough for this notebook.

I will give it a chance and buy an original HP power supply.

[beteck]

By measuring the rise there are 19V power supply between the inner conductor and outer conductor, and betweenthe center pin and outer conductor I measure 14.8V.
I measure 19V and universal in both cases.
Unfortunately I do not have the opportunity to check the noise on the output voltage :(

[Nicker321]

Again I have connected the power supply, switched the Notebook on and tried to measure the voltages of the power supply at the contacts of the motherboard.

On the inner side it reads 20,8V, the center pin reads 6,5V. Hm, I will try a new original psu from HP, may be the "100% compatible universal psu for HP 67xx" I have bought from a dealer in the internet is cheap crap from China and does not really give the voltages the HP notebook needs to start.

[Nicker321]

Yesterday I have received the new HP power supply...heart beating...nothing has changed, same error.

Tried a new motherboard I have bought from a dealer in the USA...same error.

Now I think there must be a curse on this notebook.

Last attempt: I will bye a new fan/heatsink. The fan has 4 pins and maybe the one (I don`t know its function) gives a necessary information to the motherboard. Which now failes, because the fan is defected...?.

[DuaneWong]

I do not think a new fan/ heat sink will solve the problem. I think it might be one of the daughterboards but which one I don't know.

[Nicker321]

Hi Duane,

I have tried to start it without all the daughterboards connected...no chance.

Now the only thing I can imagine is a defected fan (may be a signal failed) oder again a defected motherboard...but I don`t really think that I have received 4 broken motherboards during all the time since october of last year.

What the hell...

[DuaneWong]

I know it will not start without a daughterboard connected, but that's what seems to be bad in light of all those motherboards you tried from China, Germany, and the US.

[Nicker321]

I have bought a new HP original power supply, I have exchanged the soundboard and the cardreader but still it will not start. 5 times blinking and the HDD led blinks in the rythm of a reset, like the sound of the fan.

Has anyone a good idea? I am at the end, I don`t know whats going on there...

[DuaneWong]

This one is quite a mystery. If you replace virtually all of the circuitry with the boards inside the computer then what else could it be? Sorry, that you couldn't fix the problem on your laptop using logic and common sense. It seems like you have gone to great lengths to repair the problem without getting to the actual answer as to how to get this notebook working again. 

[R3d_D3vil999]

Hi there...

I´m having the same problem with my 6735b, and i´m a technicion...

I think it could be a problem from the board that has the RTC battery, but i don´t have another one to test it.

So if one of you guys could test it with another of that board please try it and give your feedback.

I already had this issue, and i fix it, just by disassembly all parts (all really) and when i get it all mounted the laptop just start to function saying that the bios was recovered (bla bla bla). it worked for 3 or 4 days and then got back to same issue (5 times blinking leds).

I know that the most common in these cases is a faulty mainboard but i like so much this laptop that i don´t want to believe it... 😞

Will be waiting for your replys...

Best Regards