Strange power-on behaviour on a precision 7520

Question

Hello, this is my first post

About 6 weeks ago, I got a used precision 7520 from Ebay. After some time I accidentally came across a strange issue, where if it's left plugged in after turning it off, the battery led will come on and stay on (without battery) blinking every 15 seconds or so, and the laptop doesnt turn back on. it would do the same after disconecting and connection it again, It also wouldnt turn on with just the battery. I found out, again by accident, how to turn it on; you need to push the power button at the exact moment the led blinks. One day i connected it with the battery on, and it turned on normally, after charging the battery completely, I turned it off, and it was back to normal. the issue didnt come back until a couple of days ago, but this time the battery charging "solution" didnt work (draining residual power works sometimes). idk what's going on, is this some sort of undocumented feature? is it hardware failure? I'm at loss here.

Thanks for your attention

DELL-Cares · Answer

We tried reaching you on a private message asking for the Service Tag number to ascertain the warranty but did not receive a response. Please feel free to reply to the private message whenever you are available.

Chino de Oro · Answer

It's not strange for a laptop to alert its user that something was wrong with the battery. The blinking was to alert you that you were charging the laptop without a battery. If you were to unplug the AC charger, it would stop blinking.

If you are having trouble charging your battery, maybe it's going bad and time for a new one. Did you run a battery report or checking for battery health in diagnostics?

sknk · Answer

Hey The battery is 100% healthy. Perhaps My first post wasn't very clear, English is not My native language. basically that blinking thing is the 'default' rn, I have to press the power button at the exact moment it blinks to turn the laptop on. Also, it's not possible to turn on the laptop with just the battery, even if it's fully charged.  It's very strange, hope that was clearer

Chino de Oro · Answer

If you think your laptop is working normal, then there is nothing else to discuss here.

Or, you can refer to the service manual for further troubleshooting.

Battery status lights

If the computer is connected to an electrical outlet, the battery light operates as follows:

Alternately blinking amber light and white light: An unauthenticated or unsupported non-Dell AC adapter is attached to your laptop. Re-plug battery connector, replace battery if the issue reoccurs.
Alternately blinking amber light with steady white light: Temporary battery failure with AC adapter present. Re-plug battery connector, replace battery if the issue reoccurs.
Constantly blinking amber light: Fatal battery failure with AC adapter present. Fetal battery, replace the battery.
Light off: Battery in full charge mode with AC adapter present.
White light on: Battery in charge mode with AC adapter present.

sknk · Answer

When I Say 'default', I mean it is exhibiting that behaviour all the time. All that I've described is very very far from normal

Chino de Oro · Answer

To help with identifying and solving any power issue, provide the following info:

* Run the command powercfg /batteryreport and post screenshot here.

* Run ePSA, select configuration tab and note the information for battery cycles, full capacity, and battery health. Post them here.

* With the battery installed and system shutdown, plug in the AC adapter and describing the battery status lights here.

sknk · Answer

the battery led is behaving as I've described before: it stays on, blinking once every 17 seconds. One thing I forgot to note, is that the "blink" is more like a sequence that happens in a split second, that is, the battery led swtches off, the power led tries to switch on, then the battery led switches on again. Hope this helps

Chino de Oro · Answer

There are 72Whr /88Whr / and 91Whr, you have a 88Whr battery.

Based on mfg. date and charged cycles (4), the battery is a replacement and at 96% life (84Whr), which is excellent.

A normal behavior is, upon connected to electricity, battery led will blink once (detection) and turning on and stay on solid (charging battery), or stay off (battery fully charged),

There are three indicator lights at the front edge, power indicator, hard drive activity, and battery light. With abnormal behavior of battery light, I'd say borrow and test with a different oem AC adapter, preferably a 180w adapter (or 240w adapter).

With the elimination process, you are left with the AC adapter or motherboard charging circuit. If the AC adapter passed the test (the issue is persisted with other adapters), it's left with motherboard.

I'd say leaving the motherboard alone as considering the repair cost, you can live with it (issue).

sknk · Answer

Yeah, I was thinking the same about leaving it alone for the time being, but I'm still concerned if this might affect the other components in some way. i'm yet to try another Charger, but I think i know where to borrow one

Anyways thank You for your help, really appreciate it

Precision Mobile Workstations

Strange power-on behaviour on a precision 7520

Battery status lights

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