AC adapter hissing

[carpenoctem]

Hey all,

The plug on my old ac adapter broke a month or so ago. I have an acer
c110. I went to fry's but they didn't have a suitable replacement. I
bought a multiplug/multivoltage power adapter and spliced the
connector to my old adapter (the connector was the broken part on teh
old one). This worked but the size wasn't correct so the plug would fall
out of the laptop any time you moved it (or the wind blew). I ran w/
this for about 2 weeks.

That is the background. Recently, I ebayed a replacement adapter. I
plugged it in and it worked fine. Except... shortly after you plug it
in a slight hissing/squeaking becomes audible. It seems to get louder
and louder until I, out of fear for the delicate internals, diconnect
it. The sound is almost certainly electricity arcing, it is very
reminicent of that experiment from science class where you can see
elec. arc up the two poles.

My questions are these:
1. Is this going to hurt the laptop?
2. Even if it doesn't hurt it, it is going to drive me insane. How
can I stop it. I was thinking of maybe some sort of conductive goo?
3. Is the problem most likely in the plug or the adapter itself. ie.
Can I splice the new head onto the old adapter?


Thanx for your time.
ej

 

[Tom Biasi]

Hey all,

The plug on my old ac adapter broke a month or so ago. I have an acer
c110. I went to fry's but they didn't have a suitable replacement. I
bought a multiplug/multivoltage power adapter and spliced the
connector to my old adapter (the connector was the broken part on teh
old one). This worked but the size wasn't correct so the plug would fall
out of the laptop any time you moved it (or the wind blew). I ran w/
this for about 2 weeks.

That is the background. Recently, I ebayed a replacement adapter. I
plugged it in and it worked fine. Except... shortly after you plug it
in a slight hissing/squeaking becomes audible. It seems to get louder
and louder until I, out of fear for the delicate internals, diconnect
it. The sound is almost certainly electricity arcing, it is very
reminicent of that experiment from science class where you can see
elec. arc up the two poles.

My questions are these:
1. Is this going to hurt the laptop?
2. Even if it doesn't hurt it, it is going to drive me insane. How
can I stop it. I was thinking of maybe some sort of conductive goo?
3. Is the problem most likely in the plug or the adapter itself. ie.
Can I splice the new head onto the old adapter?


Thanx for your time.
ej

Hi,
From your description I really don't know what is happening. The high
voltage type arc that you describe is not likely. Probably switching supply
noise, at any rate I wouldn't use it on a computer.
Tom

 

[carpenoctem]

at any rate I wouldn't use it on a computer.

Yeah, that's what I figured. I am not seeing the arc but the sound is
very reminscent of it. it builds up and then "pops" and then starts
from the lowest again. at least once or twice a second.

do you think this would more likely be a problem w/ the connector that
plugs into the computer or hte power adapter itself? The sound is
definitely from the connector.

thanx for your time
ej

 

[Gerry Cohn]

Hey all,

The plug on my old ac adapter broke a month or so ago. I have an acer
c110. I went to fry's but they didn't have a suitable replacement. I
bought a multiplug/multivoltage power adapter and spliced the
connector to my old adapter (the connector was the broken part on teh
old one). This worked but the size wasn't correct so the plug would fall
out of the laptop any time you moved it (or the wind blew). I ran w/
this for about 2 weeks.

That is the background. Recently, I ebayed a replacement adapter. I
plugged it in and it worked fine. Except... shortly after you plug it
in a slight hissing/squeaking becomes audible. It seems to get louder
and louder until I, out of fear for the delicate internals, diconnect
it. The sound is almost certainly electricity arcing, it is very
reminicent of that experiment from science class where you can see
elec. arc up the two poles.

My questions are these:
1. Is this going to hurt the laptop?
2. Even if it doesn't hurt it, it is going to drive me insane. How
can I stop it. I was thinking of maybe some sort of conductive goo?
3. Is the problem most likely in the plug or the adapter itself. ie.
Can I splice the new head onto the old adapter?


Thanx for your time.
ej

Hi,
I have had to service several Acer machines because they use a really crappy
PCB mounted
connector for the power inlet. I have found that the soldering of this
connector to the board is
often very poor. In three of the last four Acers that I have looked at I
found dry solder joints on
this connector. Every one of these machines had the same 'hissing' sound
that yoy refer to.
The problem appears to be tarnished pins on the connector not soldering
properly
when the boards go over the wave. It looks like Acer have used batch of
ancient surplus stock
that they have aquired at some stage.
The problem takes a while to show up, but show up it will, as you have now
found.
After working on these machines for a while, I have permanently sworn off
Acer.
The build quality is questionable to say the least.

Your best bet, if you are confortable doing so, is to open up the machine
and extract the main board.
You will find a plastic guard sheet in the top right corner of the machine
under the area where the power
inlet connector is located. This sheet is attached with double adhesive and
will have to be gently peeled
back in order to re-solder the connector, Make sure you use solder with a
very active flux to overcone the
tarnish on the pins. After soldering, gently rock the connector from side to
side. If it is properly soldered it should
not move. If the solder joint is dry you will notice the terminal on the
side of the connector moving in the PCB.

HTH
Gerry

** The ultimate oxymoron - An Honest Politician! **