Toshiba Satellite L350 - Issue with Backlight

[DanF]

The issue seems to happen when the display goes to sleep, and then waking it up (i.e. moving the mouse pointer). You can see the screen comes on for a fraction of a second then the backlight is off. You're still able to see the display by using some lighting.

When the system is shut down and turned on again, the display works fine.

Do you think this is a screen issue?

 

[sapphirescales]

Neuter the Windows Update service then install the display driver from the manufacturer's website. It should work fine.

I'm having a similar issue with an HP laptop right now. As soon as it installs the display driver from Windows Update, the computer freezes up and slows down the a crawl. Unfortunately setting it to not install driver updates automatically doesn't fix it. Even mucking around in the registry doesn't fix it. Windows deletes the registry entry when you install the latest updates. Windows 10 is a freaking nightmare. Neutering seems to be the only way to keep these systems from sabotaging themselves.

 

[DanF]

It works fine on the external display. So that might be hinting towards a faulty display. I just never seen a display's backlight going off when you're "waking" the display.

 

[Larry Sabo]

That's a really old laptop and probably not worth the effort, but you could try a new inverter. That would probably fix it, only to have the NEC Tokin cap fail.

 

[DanF]

Yeah, this seems like a cheapo customer I've attracted recently. Got 2 laptops from him and he didn't want to replace the HDD on the first one cause of the price. This one will end up costing around the same or more.

Thankfully I charge for the diagnoses if the work is not accepted.

 

[backwoodsman]

I'd boot it from a Linux disk and see if the issue is still there. That'll tell you for sure whether it's a hardware or software problem.

 

[Markverhyden]

Have you flashed/re-flashed the firmware to the latest version?

 

[DanF]

Yes firmware updated.
Haven't tried with Linux yet. But it also happens in BIOS... so it's not a Windows issue.

 

[Markverhyden]

@DanF forgot to ask. Get me the full model number as I should be able to get the service manual.

 

[NYJimbo]

You might want to reset all power options to defaults and check bios for any screen brightness/power settings.

 

[DanF]

psld8e-00d008en

Thanks

@DanF forgot to ask. Get me the full model number as I should be able to get the service manual.

 

[DanF]

BIOS settings in BIOS were reset, and not much display options (other than choosing how it deals with external displays).
Power Settings in Windows reset, but it shouldn't be OS related since the backlight can also go off in BIOS. Also, cannot seem to find any decently priced inverter.

You might want to reset all power options to defaults and check bios for any screen brightness/power settings.

 

[Markverhyden]

psld8e-00d008en

Thanks

Ok. Looks like my Toshiba access is only for certain countries/regions. Got the message below.


But it still should be good as the things that are usually different are parts like keyboards. This manual is for a psld8c

https://central-it-service.com/owncloud/index.php/s/54j1Elkm3NjcXjf

 

[DanF]

Thanks... everything seems to hint to the inverter. The question would be if it's worth proceeding or not (which probably isn't).

 

[Markverhyden]

If it runs all day and this only happens waking up from it might be something other than hardware. If it was me I'd pop in a new drive and do a quick install of the same version OS, updates, drivers, etc and see if it replicates. Doing a Linux test can help. But I've had laptops that Linux with X Windows that ran perfectly all day long but would BSD all the time with Windoze.

 

[DanF]

Yeah but then it also happened in BIOS (noticed it after the OP - #8).

 

[Markverhyden]

Yeah but then it also happened in BIOS (noticed it after the OP - #8).

Ahh... I see, I see said the blind man. LOL!!! Missed that part. So it's most likely the inverter, but as @Larry Sabo mentioned it's really old. Not sure how cheap an inverter would be in your neck of the woods.

 

[DanF]

Can't even find one that ships to my country on eBay, otherwise I would just get one and try it out (since they're usually cheap).

Are all inverters basically the same if the connectors match? I have a spare one with the same connections (possibly from an old Acer or HP), but still got the same result. However, I cannot tell if it's functioning at all (it surely was, otherwise I wouldn't keep it in stock).

 

[Markverhyden]

The inverter specs is dependent on the bulb. So technically they may vary but I think to keep costs low the OEM's only use a handful of different models. You can test voltages to get a handle as well. Very carefully of course. And only on the source side coming from the motherboard. Maybe you have another laptop lid lying around you could pull the FL from to use for testing. By the way the link that @Larry Sabo will ship to Malta. But it's not cheap. Postage is over 32 USD. On the main page where it says ship to click on the See details link.

 

[NJW]

I've never seen a laptop that switches off the display backlight when showing BIOS settings – that doesn't mean it can't happen, just that I've never seen it. Toshibas have all sorts of non-standard stuff in BIOS and ACPI, so booting from Linux may not give conclusive results.

As you get the same symptoms with a different inverter, I'd look at the display panel. It's quite possible that the backlight tube fails to maintain after striking when it is warm, but it will run all day if it's left on.