Windows 7: Power options problem

Have a Toshiba Satellite L550 i5 8GB RAM 120GB Crucial M4 running Home premium 7 and I am having a problem with the screen going bright on unplugging the power supply and onto battery then reverting back to a dimmer screen when power is plugged back in.

Have tried all the settings in Power Options with no difference in any of the options.

I do notice that usually when one move the brightness control slider for power in say high power settings the brightness of the screen does not change as one moves the slider.

Anyone got any suggestions for cause please as I am thinking maybe my power adaptor is failing.

I saw this post this morning. I'm surprised no one has responded.

I would check to see if there are any power options in BIOS settings. Not usual for a laptop, but worth checking. Be sure they are enabled and either S1 or S3.

If that looks OK you could try this MrFixIt:
Fix power consumption problems and extend the laptop battery life
Described here (MS link is broken):
Reset, Fix Power Options In Windows 7 [How-To]

You could also create a new power plan, name it "Diagnostic", and maximize all settings (Never, Never, Never... Full Brightness, etc) and see if it does the same thing.

And you could also create a new user, create the Diagnostic plan, and try that. See if anything changes that might shed light on the cause.

Hope that helps!

OK TV I'll take a look at the BIOS then try some of those other options.

I thought for a while it might be the adaptor was going to heaven but it's putting out 23.1v although it is marked as 19v but am thinking too that any "extra" would be dealt with eh regulators inside eh?

No, I think too much juice can be just as bad as too little. So I would not rule the PS out.

Just try all the free stuff before you go out and buy parts I always say!

Ok mate I'll do that as Toshiba tell me that that voltage is ok but like you I am not so sure and I am rather dubious re those call centres that are not necessarily in ones own country.

Now I have just before posting this checked in the BIOS and found that changing the power setting to this screen only has restored the brightness control.

Thanks TV I wouldn't have checked there I really appreciate the heads up

John

I too would not have ruled out that power supply too quickly. I know the devices/machines can tolerate voltage extremes within reason, but 20%+ (4v) above rated seems a little too extreme.

Yes Fsing I might have acted in haste a the darn thing went again on me about half an hour ago, and I reset the BIOS again back to using any monitor.

The BIOS has two settings one that is just for the dedicated one and another for attached monitors, and is not found in the Power section of the BIOS I think (I will have to recheck) it is in System configuration in the Advanced section.

Anyway I think you are both right I should take a second look at the extra volts issue even though Toshiba said that it was normal.

Now I know from back in the days when I first became interested in electronics that adaptors were usually supplied by a greater voltage of AC which allowed for the loss (drop) in the DC output the extra energy being lost in heat and current flow through the dedicated parts.
I have to admit this was during the 60's and 70's before integrated circuits were really the affordable devices (to me at least) they are today.

Kind of the way I remember it. AC loses energy at constant voltage, DC loses voltage at constant energy. Energy being amps I guess. Something like that.

Got a couple universal laptop chargers (as well as a bunch of regular laptop chargers). Cannot remember measured output (I'd measure for you but someone's got my only meter). But both were advertised as working for anything requiring 16 to 19vDC. One referenced on the packaging that it adjusted its output voltage to match the device it was connected to. Skeptical of that claim though. How would it know? I imagine it would put out a relatively constant working voltage and the device would handle it. Used it on many, many machines though and it's always worked.

Supposedly there are some Dells out there that can recognize a non-Dell charger (guess their chargers have a proprietary signal superimposed on top of the DC). Will let you power but not charge, but every Dell that I've connected it to has powered as well as charged.

Sorry can't help with your issue, just thought I'd let you know I thought 23v just seemed way too high to me. Could very well be way off base here, just something to consider.

Yeah F5ing I used to be able to work out the voltage drops, current losses, through something as simple as passage of the electrical current through components such as even the very basic ones like resistors, caps, transistors, vacuum tubes and even the cables themselves.

Well I guess you already know all that some of that energy is converted into heat which we all know today is so important to get rid of before it destroys the components using said current, and one source that very familiar to us all in notably the CPU

Anyway sorry mate but did I quote 23v it is actually 21.3v which still in my mind is too high at the DC socket of the adaptor as it definitely states it's output is 19v and I could accept say 1v difference - allowing for fluctuations in the AC voltage.

Having said that in reality the voltage regulators in those devices should well regulate to within say +/- 0.015 tolerance but closer to 2.5v - hum? I mean it isn't rockets science as have built many adaptors for various purposes and one just adjusts until one gets those tolerances - or doe one?? Perhaps not in China?

21.3 doesn't sound near as bad, but like you say, I would expect a little closer to rated and still sounds a tad high. I do wonder about supply voltage though as you mention. I've got about 5 to 6vAC variation here depending on loads, about 4% or a little more (guess you could say +/-2%). Gonna have to test that.