Satellite C55-A-142 Laptop boots only without battery

[doboka98]

Hello! I am fixing a Toshiba Satellite C55-A-142 (model no PSCG8E).

It came with an old battery. Laptop was rebooting every 5 sec with black screen, not even entering BIOS. If battery was removed it worked perfectly only on charger. I thought it's a shorted battery so I ordered a new one.
Now with the new one it wont even reboot, but the red battery light is blinking on the laptop. Pressing the power button does nothing. Laptop still works with battery removed.

So to summarize:
1. there is no short
2. Laptop starts only with battery disconnected.
3. With old battery inserted and AC in it kept restarting over again, without entering BIOS
4. With new battery it doesnt even start, just battery light blinking. Not even with AC in.

Please advise. Thank you
I am a beginner.

[mon2]

Re: Satellite C55-A-142 Laptop boots only without battery

Hi.

1) review the above sticky thread on chargers by @Piernov. It is a must read.

2) most likely you have a defective mosfet onboard. The charger ics will drive dcin mosfets (usually 2) from the adapter side and another from the battery side. If one or more is defective, you will this issue.

3) post a link only for the schematic for this logic board. Only if the schematic is in the dedicated forum. If not known, share pics of the white silk screen from your logic board.

4) remove all power. Meter in resistance mode. Review the resistance between the dcin mosfets and also do the same for the battery mosfet.

Check for each:

Source & drain
Source & gate
Gate & drain

A low resistance means the mosfet is defective.

[doboka98]

Re: Satellite C55-A-142 Laptop boots only without battery

Thank you for helping.

I have checked all 3 mosfets and all of them have resistance between everything. Resistances are well above kOhms.
I guess the DC in mosfets should be OK theoretically too because without the battery the laptop works fine. This only happens when I plug in the battery.

[doboka98]

Re: Satellite C55-A-142 Laptop boots only without battery

Im not sure what you mean by point 3.
Could you elaborate please?

[mon2]

Re: Satellite C55-A-142 Laptop boots only without battery

If the schematic is available then provide the link here but do not post the schematic here. Instead, post it in the schematic only forum.

Do post the resistance readings because low K values are not good for mosfets.

Is the battery charged?

Review the battery mosfet.

One of these mosfets is leaking and causing this issue. When the power adapter is connected, what is the voltage to ground of each pin of each of the dcin mosfets? The battery mosfet? (Without the battery connected)

[kalisko]

Re: Satellite C55-A-142 Laptop boots only without battery

Insert the correct battery, the problem will be solved..
That's how I solved the problem.
greeting

[doboka98]

Re: Satellite C55-A-142 Laptop boots only without battery

Thank you for the responses.

Battery mosfet with DC in (without battery): 3.11 on the source and gate. 19.19 on drain.
Battery mosfet with battery: 10.8 on source and drain, 16.9 on gate.

DC in mosfets with DC in(without battery): 19.3 on source and drain, 24.7 on gate.

Resistance readings:


Battery mosf:

gate to source: 0.39 mOhm
gate to drain: rising to infinite
source to drain: rising to infinite.

[doboka98]

Re: Satellite C55-A-142 Laptop boots only without battery

Battery is charged. Orange battery light is blinking on the laptop. When I remove the battery from the slot, the power on light will light up for like 0.2secs. Just a tiny blink.

Voltage is present all over the board with battery.

[doboka98]

Re: Satellite C55-A-142 Laptop boots only without battery

Update!
Replacement battery was faulty. Ordered a new one and everything works fine.
Had to uninstall battery controller modules from Windows in device manager.
It reinstalled itself and recognized the battery instantly.
Thanks for all the help.

[kalisko]

Re: Satellite C55-A-142 Laptop boots only without battery

Update!
Replacement battery was faulty. Ordered a new one and everything works fine.
Had to uninstall battery controller modules from Windows in device manager.
It reinstalled itself and recognized the battery instantly.
Thanks for all the help.

Post no. #6