Black Screen, Hissing P-7805u

Hi there, I'm Klokinator, and I recently (35 minutes ago) started having a major issue with my Gateway FX 7805u. I did a lot of googling about it (In fact most of my finds came up on this forum which is why I'm posting here) and found a bunch of fixes but they didn't seem to be for the exact problem that I'm having, so I wanted to do some double checking.

So I bought this laptop about 5 months ago and aside from microstutters (Which annoyed me, then I found out it was to prevent the GPU from overheating?) it worked great. Never an issue with it. It suddenly, from out of nowhere, while plugged into a wall, made a slight hissing noise, and when I leaned in to listen to it (IUt sounds like it comes from around the base of the monitor) the screen started flickering, then there was a BZZT sound and it went pitch black. I immediately turned it off (to my misfortune, windows decided "hey this is the perfect time to force an update on you" >.>) and have not touched it since. I unplugged it from the power also.

I heard that sometimes the issue is caused by a power cord failure, but it has always worked fine whether on battery or plugged into the wall. Now it does the hissing and sputtering then black screen whether on battery or plugged in, and regardless of any activity being performed on it. From this, I'm guessing the issue is the power supply (I do NOT have the money for a new power supply) but I'm praying something cheap is the solution. I'm in a college so I don't exactly have tools available but I could procure them if necessary.

If anyone can help me out, I'd really appreciate it.


Edit: Also I am aware of the Targus 180w power adaptor, so if that's something I need to buy I am planning to do so.

 

I don't like double posting, but this is sort of important and an emergency as I have a lot of homework due soon and if I can't get this fixed tonight, I'll need to come up with an alternative. If anyone can offer any help, I'd really appreciate it.

 

It definitely won't be fixed tonight so go for that alternative arrangement.

This may even be a fried motherboard so don't count on a cheap and quick fix.

 

Is there any reason my motherboard would randomly fry like that? I can't see why, I was just chatting on skype. It's not like I was playing GTA4 for a few hours on high details :<

Edit: Also apparently a motherboard repair is cheaper than a power supply. That's something to look forward to.

http://www.ebay.com/itm/GATEWAY-P-6...454?pt=LH_DefaultDomain_0&hash=item1c24572a06

 

Buzzing and hissing are most likely the caps and/or internal transformer coils taking a dump. This could have been from a bad brick that just was barely keeping up and supplying flakey power to the system. The bad here is the mb could be shot by this or it could just be a power board. I would not take it apart though to start throwing good money after bad.....................

Edit; I should note a bad brick can hiss too......................

 

Some other details:

It hisses whether it's plugged in or whether the battery is in or out. I had it plugged in with no battery and it hissed, so I'm ruling out the battery as the cause. It could be the power plug except it also hissed when the battery was in, so that might not be the cause. I can see images on my screen but they look ghosty, like the brightness dropped from 100 to 1. If I close the monitor lid and open it, the screen becomes bright again and then flickers, and dies within 5-15 seconds.

Do with this information what you will. I'm considering getting an external monitor as a quick fix. If the motherboard is shot, shouldn't the pc not work at all? It still works fine, aside from the hissing and dead display there are no other issues. I hope this helps narrow the problem down.

 

Okay, sorry for double posting again, but I need to ask this. Um, the monitor appears to be working fine, it's just super dim. Based on what I can see, it just looks like the backlight is the issue? Perhaps the backlight isn't getting enough power or something, which may mean I need a new power supply/adaptor, or are there possibly any tutorials on youtube for fixing/cleaning the connectors and etc for the backlight?

 

The backlight can be an issue. If under battery power the backlight still goes out then the likelihood the brick is an issue is extremely limited. It could be the inverter or just a bad connection internally. So in the end the problem you have is not black screening but severe dimming or back light loss. Both of course are entire different issues.

Try turning the display brightness way down and see if it will hold out longer before issues arise...............

 

I tried doing that but unfortunately that did not work. Do you think that buying the new power brick would at all help? I don't want to spend $18 if there's no point but I'd be willing to maybe get a toolset and try taking apart my laptop to make sure the connections work.

What exactly is this part? What does it do and how does it function?

I'm pretty sure it's dimming issues. Lowering the brightness doesn't help (The screen only lasts for 15-15 seconds anyway and it's lasting less and less long.)

Thanks for the replies, I'm really appreciating the support guys

 

If under battery only power or AC power the backlight goes out then a new brick probably will not help. Hissing is usually a coil, the oil overheating within it and you hear the hiss. Now hissing or more likely whistling is usually a capacitor. Now hissing can sometimes be attributed to arching, why I suggest looking at the contacts. I am sorry but without being there this is an extremely hard issue to diagnose with a definitive answer.

My suggestion is take it to a tech who is capable of soldering components on a main board along with doing proper circuitry diagnosis. And do this before it completely dies so they can see and hear the issue.......................

 

So I went back to my dorm last night and turned it on. After I carefully navigated to power management, I managed to turn the brightness to lowest. When I did that and closed and opened the lid, the backlight came on and stayed on! Only thing is, the hissing was very faint. In fact, the higher the backlight was set the louder the hissing was. I do think it's a connection error,m and in fact I remember having screen issues that weren't nearly this bad over the last month. My screen kept having slightly darkened patches on it, like the bottom left corner would be a slightly reddish hue compared to the rest of the screen.

Based on this I'm guessing connection error or something to do with the wires. The hissing sound appears to be above the topmost volume control (the touch sensitive part) so I guess that's where the tech will look first. Thanks for the help, I really appreciate it

 

Based on the hissing being correlated with screen brightness I would expect the inverter to be the problem.

 

I'm still not sure what the inverter is. What is it, and is it fixable? Also how much $$ because I hope it isn't too much...

Edit: Ah, maybe this. http://www.laptopsinverters.net/gateway-p7805u-fx-laptop-inverter-p-5605.html

Doesn't seem to be such a bad fix, and it sounds exactly like the problem I'm having. I'll look into this, thanks for the help guys!

 

Yeah- that's an inverter. These are cheap and easy to replace.

 

Perfect! Problem solved, you guys are the best

 

Probability is yes it can be the inverter, without being there though remember this is a probability not a certainty. as an example from below links. Also it seems the transformer for the inverter may not be located on the inverter itself.

Need help - Humming/hissing sound from Toshiba Laptop - Technibble Forums

LCD Inverter - Internal Hardware

http://www.creativeit.tv/laptop-backlight-repair.htm

http://www.experts-exchange.com/Hardware/Laptops_Notebooks/Q_27783927.html

http://www.hardwareanalysis.com/content/topic/50620/

 

Hi all: I been having problems with my FX7805U. When I play COD4, MW3, WOT. I play for 20, 30 or one hour. But eventually my screen goes dark, but there audio and I can talk to people in Team Speak. I have tried lower the 9800M GTS Clocks and the x9100 to 1.225V and still having problems. I have recently cleaned my computer and put the x9100.