Strangest laptop power issues ever (like a bad riddle...)

[fluty]

Story time, thanks for reading! See if you can solve my "riddle"...

So I bought a like-new (not refurbished) IBuyPower laptop from eBay and used it with no issues for 4 months. I keep the fully charged battery out of the computer and always run using the ac adapter only. One day I noticed that the "c" key and the "1", "2", and "3" keys on the keypad did not work (number line 1 2 and 3 worked fine) but if I mashed them enough, eventually it would. Then I packed it up to bring it to class with me, plugged it in, and found that it would not power on at all (no lights or anything). It did not turn on that night, even with the battery in. I brought the laptop to a parts store the next day, where the laptop instantly started up using their universal adapter, all keys working. I was told it was my ac adapter and that a new one would cost $100 dollars. But why didn't my battery work to turn it on? Anyway, I bought the universal ac adadpter he recommended in place of the expensive retail adapter (I later found out that the new supply had a current of 6.5A instead of the 9.5A the previous supply provided; I kinda figured he knew what he was doing, he actually said the new supply was more powerful! Wrong.). Yet, it worked great for three days on the new adapter, until the same 4 keys went bad again, and the next time I shut it down it did not turn on again. It was the week before finals, so after a bit of tinkering with the power button and many failed attempts, the laptop actually booted up. I kept it on all week, using the new adapter, never shutting down, and just pasteing my "c" when I needed it. Yes, the laptop works 100% fine besides those keys when on. After finals I crossed my fingers and shut it down, it did not boot for the next three days so I sent it to the manufacturer for repair (still under 1 yr warranty). I did not send them my battery or ac adapter as how could this be a power issue when the battery isn't booting it either. They had it for 3 weeks and said they could not duplicate my problems (using their ac adapter/battery). I receive it back (but they didn't charge me for the "false" repair request...) plug in the same universal adapter, and everything is fine until day two when the adapter melts during a graphic intense game. Naturally my laptop turns off immediately. The battery ran it fine when I put it in. I find my old retail supply and plug it in with the battery still in, boot up, and immediately the 4 keys stop working. Even when running just on battery power, the keys don't work. Now I'm afraid to shut down the laptop for fear of it not booting.

I tested the retail adapter with a multimeter. It is rated at 19V but read 17.6V . Is it my ac adapter? but my battery too? or is the power supply "charging" my motherboard? But why did it happen when using new supply as well? The computer did not boot for THREE DAYS, yet booted fine when it showed up for repair using their power supply. I just don't know anymore. I mean, when booted, the battery works great and the power supply does its thing. But when it is shut down, it will not turn on using either option. I may be able to persuade it to turn on after random "tinkerings" (Pressing/holding the power button, unnattaching and reattaching the power button ribbon, switching from wall power to battery, disconnecting all power and waiting, etc), but none are guaranteed to work. Oh and by the way, the keyboard is spotless, those keys are beautiful inside and out. So what is going on here?

So, thank you very much for reading, I know that was really long. Please refrain from posting opinions about the computer brand. Let me know if you need to know anything else. This community rocks! Long time guest, first time user

 

[nukemaster]

Honestly sounds like you have more than one problem.

I would almost lean to a bad keyboard because the entire keyboard should get power from one location. This would have it ALL work or not work at all.

As far as the power supply voltage, That does not seem right for a switching power supply(as an example my HP power supply meters 0.25 volts over), but at the same time, you meter is a very low load and not all power supplies stay in spec at such low loads.

The universal power supply having that low of a rating would explain its failure, but in honesty, it should have just shut off and not failed like that(assuming it was of rather poor quality.).

The computer as its own voltage regulators that should drop the incoming power down to whatever is needed to charge the battery. Now if you get too close to the charging voltage, the regulator/charger may fail to work properly for sure.

You can see if HWmon will see your battery voltage, but again, when the battery voltage gets too low, the system should warn you and then shut down.
http/www.cpuid.com/softwares/hwmonitor.html

I would give another call to iBuyPower to see what they have to say, because you did not send the adapter and battery, they did not have the FULL system to test with.

 

[RetiredChief]

Just checked 2 AC adaptors, one for a Samsung 17" laptop and a 14" HP.
Both are rated at 19 VDC @ 4.7A.
... The Current rating is that the Output voltage will be 19 VDC up to 4.7 Amps.
.. Both read slightly above 19VDC when NO load is connected (19.1 and 19.2 V).

.. If you read 17 VDC with NO load connected then the adaptor is NOT meeting it's specs. Generally the output will drop as the load current increases ABOVE rated current.
Bottom Line on adaptor - I would not use as it is defective if not outputing 19+V with NO load, Who knows what the output is when loaded and what the Ripple looks like!!

Laptop key problem and not booting with a charged battery (AC adaptor not connected) indicates an internal intermitten problem with the laptop itself.

General comment, you did not mention the type of battery ie is it the NiMH or a Li-ion battery as they have different characteristics.
.. Neither type like Being charged to 100% all the time.
.. NiMH and NiCD should be "run down" periodically (Never go below 1 V per cell).
.. Li-ion (The most common on newer laptops) should be charged when they hit about 20% (DO not discharge completely) and recharged to about 90%. If discharged below a given point there is a protection circuit that will trip and the Battery can NOT be recharged except with a speacial charger.

.-.-. Pretty much the same as Nuke stated, just with diferent verbage.

 

[fluty]

Thanks for the responses!

It is a 9-cell Li-ion battery. And thanks for the info about not fully charging it, I strive to keep things in as optimal condition as possible. I just purchased a new Targus Universal adapter, this time with the full 180W (19V), instead of the previous one (Prudentway brand) that only had 120W.

I do, however, directly associate the key issues with the power issues. They are always present simultaneously. The fact that the key problems started again when I plugged in the defective adapter, tells me that may be it. And I'm 95% sure if I shut down my laptop right now, it will not power on easily. But there is still the issues of the second adapter experiencing the same issues as the first after a few days. However, the repair shop used an adapter with the correct current, and after 3 weeks of "testing" they couldn't reproduce any of my issues. So if their adapter worked fine, hopefully a new one will do it right this time. There is only the matter of getting the keys to work again, but it has done this twice, both when a new adapter was used after a shut down. So I'm gonna shut her down when the new supply comes and see how difficult it is to turn on again with the new supply and see if any symptoms persist. I'm gonna use the current, retail, power supply as little as possible to get me through the next couple days.

By the way, the person that helped me test my power supply (even though I could have done it), said that sometimes the adapters will regulate the voltage to be a little different than what it is rated... Trying to say mine was OK. Really? Boy is it hard to find good help these days. I know they adapters aren't always perfect, but to my knowledge anything over 1V away is too much. Wanted to confirm that here. So a big thanks to all knowledgeable forum visitors who give their input and help the DIY man like me!

UPDATE: I received the new (but used) power adapter (Targus brand) and tested it with a multimeter: 19.18V. Much better, yes? And I shut down my computer while it was on battery after being connected to the "defective" adapter. As predicted, the laptop would not turn back on, in any combination of batter and old adapter. Now I have been trying since last night to get the computer to boot with the new, non-defective adapter (still wont turn on with the battery, as expected). In the past when it has been at this stage, it took a day to over 3 days (when I sent it in for repair) for it to power on using a new adapter. Any ideas as to what the problem could be now? or how to persuade the computer to turn on sooner? It is very unfortunate that I did not send my adapter with the laptop for repair. It was just baffling that the battery could not start the computer if the adapter was the problem... so I figured the problem was internal. And it half is... because something inside has to "de-charge" or whatever for a new adapter to work. But I bet that when the laptop turns on this time the keys will all work and hopefully I never see these problems again

 

[nukemaster]

I have only seen in spec sheets some switching units listing that regulation will not work well at ultra low loads. All my switching units TO tend to hang right at the right voltage(within a few percent)

This is all kind of backwards from a normal non regulated setup. For instance a 6 volt 500ma power supply will meter at like 9-12 volts in many cases but as soon as a load of 75 ohms is applied it drops right into place(so backwards of what you are getting).

This is why voltage regulation is so important as it minimizes these power changes. Switching power supplies do all this will less waste power.

Again, while on paper at ultra low loads, you may have some regulation issues, I have yet to see a notebook adapter out by THAT much(about 7%).

 

[fluty]

I see. Also, when I said "retail" adapter, I meant the one that came with the computer. "Stock" would have been a better word. The stock adapter is still alive and is the one I replaced with the low-current universal adapter during my first technician visit. The universal is the one that melted the day after getting my laptop back from repair and no longer lights up when plugged in---is dead. The universal could switch between voltages, but I never measured to check it, it was set to 19V. Thus, I switched to the stock adapter (yesterday) and immediately on boot up I started having the key issues. So that is the one I tested with the multimeter today and got 17.6V. It is the original adapter.

 

[RetiredChief]

Outside chance.

.. The way a switching PS works is that it turns on and off the voltage and uses a filter in the output that converts that to an average voltage. It is possible that the filter caps are bad and the output is not a "smooth" DC but a pulsating DC that is dropping t low and the laptop input circuit can not handle it.
This would cause spikes on the output of the voltage converters in the laptop. Which can cause weird indications.

 

[fluty]

UPDATE: I received the new (but used) power adapter (Targus brand) and tested it with a multimeter: 19.18V. Much better, yes? And I shut down my computer while it was on battery after being connected to the "defective" adapter. As predicted, the laptop would not turn back on, in any combination of batter and old adapter. Now I have been trying since last night to get the computer to boot with the new, non-defective adapter (still wont turn on with the battery, as expected). In the past when it has been at this stage, it took a day to over 3 days (when I sent it in for repair) for it to power on using a new adapter. Any ideas as to what the problem could be now? or how to persuade the computer to turn on sooner? It is very unfortunate that I did not send my adapter with the laptop for repair. It was just baffling that the battery could not start the computer if the adapter was the problem... so I figured the problem was internal. And it half is... because something inside has to "de-charge" or whatever for a new adapter to work. But I bet that when the laptop turns on this time the keys will all work and hopefully I never see these problems again

 

[jarotech]

What is the make and model of your laptop ?

 

[fluty]

It's an IBuyPower "Valkyrie CZ-17".