Strange laptop PS behavior

I have a used Dell Inspiron 5558 laptop, which didn't come with an OEM power supply. I picked up a 65W "universal" type for it off Amazon, and it's showing some weird behavior.

First problem is that it often refuses to charge the battery when connected to line power. Maybe 1 out of 10 times I've plugged it in the battery charges, the other times the charging LED remains off and the charging indicator on the screen remains at 0%.

It sometimes has difficulty starting up from line power at my home as well; you have to hit the power button a couple times to get it to power on instead of coming up for a few seconds then immediately shutting down. However, it seems to always work fine off the local Starbuck's wall power. Still doesn't charge properly, though.

The BIOS reports some incidences of "Unknown AC adapter detected!" but not all the time.

Before I run out and make sure to pick up an OEM supply, is there any way to ensure this is certainly a problem with the adapter and not the PC?

Maybe a BIOS update is required?

Reply to
bitrex
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My first thought is an ID ROM chip so it won't work with a "foreign" power brick - but that should be consistent, either it works or it don't, not maybe sometimes.

Reply to
Benderthe.evilrobot

I'm not surprised.

Dell laptop power supplies have a 3rd "sense" wire (a pin in the centre of the coaxial barrel) which allows the laptop to identify whether a genuine Dell charger is being used, and without one it is likely to run at low CPU speed, and refuse to charge the battery.

Look on ebay for an appropriate PA-series, what model laptop do you have?

Reply to
Andy Burns

Duh!

Looks like you need a PA-4E power supply ...

Reply to
Andy Burns

Yes, but it's easier to just buy a replacement charger:

From your description, I would guess(tm) your replacement charger is generating some noise. The laptop charge controller is rather picky as to what voltage it's being fed. Too little voltage or noise, and it will power the laptop, but not charge the battery. I'm not sure what it will do with too much voltage. I buy these replacement power supplies from various eBay vendors in lots of 10 and resell them to customers. I've had a few problems, but in general, they work. Spend the $11 and see what happens. If a new charger doesn't fix the problem, then the problem is in the laptop and someone will need to dive in and fix it.

Note that if this machine is a lemon and out of warranty, a motherboard transplant is possible but expensive for the i7 version: Note that swapping motherboards often breaks software licenses and registrations so save this as a last resort.

Also, my sense of smell tells me that running your Dell Inspiron 15

5558 without the battery is a bad idea. A good charger should be able to run the laptop without a battery, but I don't want to find out what might happen if you try it with a potentially defective charger. Don't try it.

You should always stay up to date with the BIOS. Yes, you can find horror stories on the internet about failed updates, bricked laptops, and features that no longer work correctly. Those are rare and can be handled by with various BIOS recovery tricks. I had some bios failures maybe 10 or more years ago, but not since. Do it.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

The power plug on the Dell Inspiron 15 5558 does have a 3rd wire. Here's the replacement (clone) charger. Here's the connector: The usual problem is that the 3rd wire breaks inside the plug. The plug cannot be disassembled or easily replaced, so I have to replace the cord. At the current selling price, it's not worth the effort.

I haven't had any laptop reject clone chargers yet. Mostly they check for charger capacity. If I plug a 45 watt charger into a laptop that wants a 65 watt charger, the charger will run the laptop, but not charge the battery. Sometimes, I see a "wrong charger" message appear on some screens, but not always.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Ooops. I don't like stright power plugs because the center pin wire tends to break inside the plug. A right angle plug is easier on the connectors and uses less desk space for the cord:

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Thanks much for the advice, I'll give one of the eBay clone chargers a try!

Reply to
bitrex

Wow, that's a good price.

Have you peeked inside the brick by any chance? I saw a scary site a while back that had teardowns of some Chinese-made replacement power adapters that were all just repackaged e-waste with some wires bodged on inside...

Reply to
bitrex

With the right-angle connectors the shield wire tends to break at the joint... :-(

Reply to
bitrex

Sometimes a firmware update will fix a "plugged in, not charging" condition (it did on my Dell Studio).

The problem is that the Dell won't allow a firmware upgrade unless the battery is partially charged lest it get AC interuptus bricking the main.

There is a technique to force the computer to run the bios flash (might be as easy as putting a /force at the end of the command line.

Reply to
ohger1s

That's less likely than with the straight in connector, where the tiny center wire tends to break when you bend or flex the cord. That usually happens when the power connector is in back of the laptop, and one shoves the laptop into the wall. The cord hits the wall, bends to a sharp 90 degree angle, stretches the center wired, and eventually breaks it.

The straight in connector is also longer than the right angle connector. If the cord is pulled in the wrong direction, the connector will bend and eventually break the jack. The longer lever arm produced by the straight in plug does more damage than the shorter right angle plug.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Yep. I can't even ship an empty box for that price.

Nope. The only power supply bricks that I tear apart are the ones that have failed and where I think I have a chance at fixing. Most of the bricks are glued or solvent welded together making disassembly somewhat destructive. I have looked at various other brick power supplied and found the full range of quality from really good, to absolute crap. I don't know where this vendors bricks fit but can say I've bought a few bricks from him without any surprises or failures.

If you want photos of the guts, I can probably supply something as I vaguely recall tossing some in my "to be recycled" bin. No schematic so this might be limited to quality of construction.

Like this fake Dell PA-10 brick? Some of the stuff I see that has failed looks like this. No input protection, filtering, or isolation. Undersize filter caps, inadequate heat sink, and no isolation between input and output sections. I can't say that the stuff I've been buying on eBay is in this class because so far I have not needed to tear one apart and analyze the design.

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Jeff Liebermann     jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Thanks again for the tip, Jeff, the replacement adapter came today and is charging the laptop and seems to be working great. :-)

Reply to
bitrex

So here's the final solution. The new power adapter powered the laptop consistently, however it only charged the battery once. Then it refused to charge again.

Updating the BIOS to the latest version fixed that problem as well, so now everything is working fine. I had to use the "hack" method though, as of course I didn't realize there was a problem remaining until the battery had fully discharged, and the Windows update tool requires the battery to be above 10% to operate, as "ohger1" mentioned.

For future reference, you get Dell Diagnostic Deployment Package (DDDP) here:

and also the latest BIOS update executable. Follow the instructions to make a bootable USB flash drive with the proper DOS startup files.

Hit F12 on startup and switch the boot mode from "UEFI" to "Legacy." Restart and select the USB flash drive to boot from and a DOS prompt like "Diag C:\>" should come up.

The BIOS update file will show up with the usual "~1" at the end to represent an extended filename. On mine it was "INSPIR~1.EXE". Type "INSPIR~1.EXE /forceit" (hidden option) to force a BIOS update while on AC power with a dead battery.

After the BIOS is flashed shut down the computer, remove the battery and hold down the power switch for about 20 seconds. Reboot, switch the boot mode back to "UEFI" and boot into Windows and the charging light should come on indicating the battery is charging properly. Yay!

Reply to
bitrex

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