hello friends i have a hp 17878-1b

[ashiq]

I have a board (hp 17878-1b) with condition not charging without battery also dc jack showing orange light i have programmed ec bios and main bios still same ...anyone knows the condition pls replyy....https://www.badcaps.net/forum/images/smilies/compy.gif

[ashiq]

Re: hello friends i have a hp 17878-1b

pls help guys???

[mon2]

Re: hello friends i have a hp 17878-1b

No personal experience with EC bios programming but have you confirmed the voltage rails for the logic board ?

Are there schematics available for this laptop ? Link them if they are on this forum.

Otherwise, remove all power. Meter in resistance mode (2k scale). Check and post any low resistance to ground for the coils onboard. Each coil is linked to a local voltage switching power supply. Start with this.

You may have a damaged mosfet causing this fault. The bad mosfet can be located using resistance checks.

Post the battery charger IC markings so we can locate a typical reference schematic for a comparison.

For the mosfet checking...

Remove all power. Meter in resistance mode (2k scale is ok).

Check and post the resistance for each mosfet linked to these rails:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Searching for any low resistance values on the mosfet = most likely is a damaged part that needs to be replaced.

[mcplslg123]

Re: hello friends i have a hp 17878-1b

On some hp mb's, dc jack light remains orange without battery also(eg brittle mb on hp x360). If it is not charging, mention the charging ic used. Dc in MOSFETs are the starting point. Check voltage on D-S-G pins of dc-in MOSFETs and post here. If they are n channel gate voltage should be aprrx 24V. If P channel get are used, then u should get 6-10V on gate. Pl cnf these readings

[ashiq]

Re: hello friends i have a hp 17878-1b

There is no shorting in the board I checked.The battery is not detected in the windows having no battery symbol .i have changed the batery .the sda scl pin having 3.3v .the IC used in the board is BQ737 i have replaced the ic charging fet but still same condition.����..this board have no schematic..

[mon2]

Re: hello friends i have a hp 17878-1b

Remove all power / no battery.

Meter in DIODE mode.

Red meter probe to ground.

Black meter probe to SCL line. Post the value.

Repeat with black probe on SDA line. Post the value.