hello friends i have a hp 17878-1b
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
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Re: hello friends i have a hp 17878-1b
pls help guys??? -
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.Comment
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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 readingsComment
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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..Comment
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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.Comment
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Hello everyone, I recently found this badcaps site and super Learn Electronics Repair youtube channel. And I wanted to learn how to troubleshoot power supplies and VGA cards and how to practice soldering, since I already have a properly defective piece of them. I am currently trying to solve two problems:
I have a Gigabyte GV-RX460WF2OC-4GD type card. I managed to find the faulty MOSfet (AON6414A) on it, which I replaced. The card starts up, but after about half a minute, the MOSfet in the same position will be shorted again. Is it possible that the PWM controller driving the MOSfet... -
I tried to use this method:
Testing an N-channel MOSFET:
Step 1: Discharge the Gate (turn off the MOSFET)
Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.
Step 2: Charge the Gate (turn on the MOSFET)
Now, place the red probe on the Gate (G) and the black probe on the...09-27-2024, 03:31 AM -
Hi, I'm Daniel, and I'm new to the world of repairing motherboards.
I would like to create a table, or more likely a guideline about the voltage rails and their possible resistance rail.
I know that the motherboard design has a very big depend on the rail's resistance, but I would like to know what is the smallest value for a rail that can be acceptable. For example, I heard that some new gaming motherboards can have 0,5 Ohm resistance on the GPU rail, but on an older type, it could be a sign of a shorted GPU rail.
So, I generated a table with AI so I can... -
The board number is GU502DU. I repaired this a couple weeks ago and it came back with the same issue, same mosfet failed (PQH9201). I'm hoping that the GPU was spared this time.
I used the same replacement part (purchased from Mouser) and I'm certain the soldering was done properly since it took just as much effort to remove as before. What could cause this same mosfet to fail? I'm thinking if it was unsuitable then the others would fail too. I looked for similar failures on YTube and the mosfet was replaced with AOE6930 in one instance and AOE6932 in the other but it's possible that the... -
I have an Asus GA502D, it had a blown mosfet which I replaced and the laptop booted into windows, a few mins later it shut off, the same mosfet was blown. I thought maybe just a bad mosfet but same thing happened again, a few mins in windows and shuts off.
I have removed the mosfet and can run the laptop no problem
The MOSFET is FDPC5018SG
Can anyone point me in the direction of what could be the cause of this, could it be the controller rt3663bc?
Thanks
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