1. Home
  2. Electronics Repair
  3. Monitor hisses with power off

Monitor hisses with power off

When this "future power" (name just reeks quality eh?) 17" monitor is plugged in but not turned on it hisses. When it is powered on the hissing stops and it displays fine. More of an annoyance to my dad (whos monitor it is) but I figured if someone knew why i could take measures to correct it. I was suspecting the noise filter (ironic if so for a noise filter to actually make noise rather than just block em but hey..) The large filter cap as well as the other caps read good in the power supply side of things.

thanks!

Reply to
S
Loading thread data ...

First thing: check for a tire losing air. (sorry, couldn't resist)

You don't say if it is a CRT or not, but if it is, could this be the tube itself losing vacuum? Just a wild guess...

Reply to
Buck Frobisher

I swapped the ac filter and replaced a really burnt looking mosfet (630) but she still hisses--the hissing changes volume as you wiggle the ac filter (which is why i suspected it in the first place) maybe its one of those power regulator caps on either side or the coil immediately in behind...don't really know.

and yes its a crt and all inflatable objects have been moved from the room ;)\

it

things.

Reply to
S

Are you serious?

Reply to
Jumpster Jiver

SNAKE!!!

Reply to
DaveW

hissing

monitor

it.

filter

No if the tube were losing vacuum enough to make a hiss it would cease functioning in a fraction of a second.

More likely the inductor or transformer in the monitor's power supply has a loose core.

Reply to
James Sweet

but

A capacitor won't hiss. Sounds like something is resonating, replacing the filter is probably the easiest, or you could try to open it up and shoot some clear silicone caulk in there.

Reply to
James Sweet

tube

a

If this was the case would the hissing stop as it is powered on? I'm by far no expert, just some guy trying to learn a thing or two..

Reply to
S

far

Quite likely, when it's turned on the power consumption rises dramatically, does it have a standby mode when it's "off"?

Reply to
James Sweet

Sounds like the AC input choke is singing just like the Mits use to do.

Reply to
kip

it

things.

Reply to
Lurch

by

Replaced the larger AC choke and it made no difference--still the hissing/squealing with power off. And yes it does go into a standby mode where it will show a "no input signal" that moves slowly around the screen. I noticed there is a smaller choke in there as well but i don't have a replacement handy for this so any other suggestions would be appreciated!

Thanks!

Reply to
S

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.