External monitor issue

Hi, I'm using a 22" samsung syncmaster 226bw on my Znote 6625WD running Vista 32-bit, and I'm getting slight flickering on the external monitor. It's not the monitor, as it runs fine on my stationary computer. I'm not sure if could be settings, is anyone experiencing the same issues? Or should I send my lappy for repairs perhance.

 

Hi, here are a few suggestions.

If you are not on official zepto graphics drivers then try and install them. (Or go back to the stock drivers on your cd).
I think this improved quality of the external moniter for me. I am also using a samsung syncmaster but 19" .

Install the moniter driver, I dont think you should need to but maybe it will help.

I still get a very very slight flicker which i can notice when moving the mouse across the steam window for half life 2 but thats all.

 

I have exactly the same problem on my Znote 6224W with a HP w2207. I only get it when the AC adapter is connected. The flickering is more visible on dark areas on the screen, and is quite annoying.

If I connect the AC adapter to another power supply in the room, the flickering decreases, but it is still there. Is it the same thing with yours?

 

I got excactly the same problem with my 6324w (anyone who hasn't noticed can try to pull the power plug when connected to a external monitor), which makes it a bit irritating watching movies.

I tried another vga cable but that only made it worse, so I'm left with the felling this might have been avoided with a dvi port (or hdmi as zepto says the next gen will have)

 

So it's because of the analog signal then? Hmm, would it be possible that it is Zepto's power adapter that is interfering with the VGA-cable, and if the power cable would have been better, it would all be ok?

Do you think Zepto is willing to do something about this?

 

If I understand these comments correctly, the flicker occurs when the notebook and monitor are connected to the same power source and the flicker stops when the notebook is running on battery.

If so, I suspect that we have some sort of earth loop carrying some stray 50Hz current. Are you using 2-pin or 3-pin plugs and earthed sockets for both pieces of equipment? You may cure the problem by changing the earthing status of one of the pieces of equipment.

John

 

You've understood the problem correctly. I live in Sweden where we only have 2-pin plugs and all my sockets are earthed. I'm no electrician so I really dont know how the earth loop starts and why it exists, could you explain?

How do one change the earthing status on something?

 

It is quite common (in my experience) for equipment without earthing to float at a voltage above earth due to leakage from the power supplies (this isn't dangerous because the leakage path has a very high resistance so any current will be very small).

If your plugs are two pin then there's no built-in earthing to drain away this floating voltage. My suggestion would be to connect a wire from the metal shell of one of the plugs or sockets to an earth point. Or could you change the plug to 3-pin which connects to the earth contact in the socket?

John

 

As you probably know, the cables in Sweden look a bit different from the UK. We don't have an extra pin to connect to the earthing, instead there are two metal pieces on the sides of the plug, that connects to the socket. So I think we're ok on the cableconnection part.

Would it be possible that something is wrong with the power supply in my appartment? I haven't tried any other external screen in any other building. Maybe I should test that and see if it works.

 

You have the type F plug shown here so you should have effective earthing.

Have a read of this discussion of ground loops (also known in audio as "hum loops" because of the mains frequency hum).

John

 

This is interesting. Yesterday I switched back to my original AC adapter which is earthed, and I started getting flickers on my HP W2207 22" with my 6214W plugged in. The other AC adapter I used was a non-earthed one, which doesn't cause any flicker. So having one earthed and one non-earthed seems to fix this problem

 

This is what I would expect - you are breaking the earth loop going from the socket, through one PSU and equipment, down the shielding of the VGA cable, through the other equipment and back to the socket.

John

 

I have the exact same problem.
If I unplug the AC adapter the flickering goes off.
Only I have both plugs earthed so what's the solution knowing that all the plugs in my house are earthed. should I get like a 3 pin(2+earth) to 2 pin adapter and hook the AC adapter to that ?

Could this have been prevented by having better shielding on the AC adapter ?

 

I don't know about other countries but in Sweden we use both these:

http://www.eurogoodlife.com/images/2 Pin Plug.jpg
and these:
http://www.hastensel.se/jordad 1.jpg

The first one is not earthed, but can be plugged into an earthed socket, so it doesn't matter if the socket itself is earthed, you can still use non-earthed plugs in them.

 

Same plugs here.
That's what i was calling a 3 to 2 pin adapter. i should try that...although now that I think about it I'm not sure the wall socket is earthed. (the multi-socket I'm using is that's for sure). I'll check.
Thks for the info.

 

If both the PSU and the monitor have plugs with earth connections going into the same multi-socket then you will still have a potential earth loop, irrespective of whether the earth is earthed. You should be able to break this loop with a 2-pin unearthed adaptor on one of the plugs.

John

 

My point exactly. It doesnt matter if you put a 2-pin in an earthed socket or a non-earthed socket. The flicker occurs when both the monitor and the laptop use 3-pin connectors to earthed sockets.

This combination would work:

-----------------------earthed cable (3pin) for the monitor
--------------------- /
Earthed multi-socket -
----------------------\
----------------------- non-earthed (2pin) for the PSU

Or the other way around (3 pin for PSU and 2 pin for monitor)

 

Right that's what I thought as I was writing... I'll give that a shot once I get my znote back from zeptoland.

 

put the PSU in the earthed, cheaper if the screen goes instead of the laptop if you have some sudden thunder (or you just dont unplug) and the lightning strikes, Bigger probability that the Computer survives (I got a smoking PSU one day when I were caught by a thunder that stroke some power line right outside our house.

There were a big BOOM, some smoke and burnt out fuses. Our router was also burnt out.

(this was on my old laptop thx god. Old IBM Thnkpad A31)

 

Really ? I would have thought the AC adapter would fry without necessarily destroying the laptop. The psu acting like a resistance.

Then I'll put my 226BW in the passenger seat.

 

Even at home (and definitely when I am away) I have a surge suppressor between my computer and the power socket. There's a good chance that the PSU will go up in smoke but maybe not until after too many volts have gone through into the computer. I've known a computer get fried by a lightning strike on a phone line and the volts coming through the modem connection.

John

 

So what are you guys suggesting? Is it more possible to get the laptop burnt up if not using an earthed connection, or doesn't it really matter if the lightning strikes?

 

If the lightning strike is close then I think you will have problems with too many volts coming down the wires. A good quality surge protector might protect your equipment (and die in the process). While a good earth connection should help a surge suppressor do its job, an earth path within equipment might facilitate a current surge (and damage) within the equipment.

John

 

I'm left with a funny feeling, because in Dk we use type K adapters for grounding and Zepto ships with at type F, which can't be grounded in type K, so I'll cosider the PSU to never be grounded.

I think my flicker occured from both adapters going into the same multi-plug, at least it goes away when I used another plug (in the other end of the room) for the PSU.

 

Wow, it actually worked. Thanks a lot John!

 

:smile: