Maker Pro
Maker Pro

help to repair KVM Switch

dariush

Jun 26, 2013
6
Joined
Jun 26, 2013
Messages
6
my kvm switch model D--LINK 121 doesn't work and one buzzer sounds Thegh Thegh. i guess an alternator voltage on the board cause this but i dont know whats the sours of this alternator voltage?
do you know? help me...
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
Not sure exactly what the problem might be, but it sounds to me like you're describing
a relay problem?
Is there a relay on the board? You may have lost the diode across the relay coil, causing
the 'alternator voltage', that's buzzing your relay contacts?
 

dariush

Jun 26, 2013
6
Joined
Jun 26, 2013
Messages
6
Not sure exactly what the problem might be, but it sounds to me like you're describing
a relay problem?
Is there a relay on the board? You may have lost the diode across the relay coil, causing
the 'alternator voltage', that's buzzing your relay contacts?

i cant find any diode on the board near the relay[ NEC UB2-4 5NU ]
AND i dont have schematic of this board can you take me pls?
 

dariush

Jun 26, 2013
6
Joined
Jun 26, 2013
Messages
6
help

i cant find schematic for kvm switch model D-LINL 121
any body take me that?

Dariush ... please dont post same topic in multiple threads again
 
Last edited by a moderator:

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
Is 'kvm' the company that made your switch?
You get the most help here when you supply us with as much information as possible
about your problem.
Did you try contacting the manufacturer, and asking if it's possible to get a schematic
from them?
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
A quick Google check of relay (NEC) UB2-4 5NU, shows that it's a 4.5VDC relay.
You'd only have a diode across the coil if it was an AC relay, so I gave you the wrong
advice to check.
I see from your other post, you're trying to get a schematic of your board, which is the
best thing you can do to troubleshoot your problem.
(Try not to post questions about this problem on several different category topic headers,
or the Moderators are going to correct you. They try to keep all the questions about
one problem together, it helps with a more complete understanding of your problem)
If you successfully obtain a schematic, it will be a lot easier to isolate your problem.
The first thing to check, would be to make sure the board itself is the issue.
Are you pretty sure the signal or signals being input to your board are correct?
The second most commom problem to look for, would be a problem with the power
supply to your board. You may be picking-up AC line frequency, causing your buzzing
sound.
Are there any markings on the board itself, test point voltage values?
If there are, it would be helpful to check them, and see if the voltages on the board
are correct. That's a good place to start.
(An example is your NEC relay. When tripped, you should read about 4.5VDC on
the coil)
 

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
Messages
14,254
shrtrnd

KVM = Keyboard,Video,Mouse
they are a small unit that you plug those 3 and 2 computers into
designed to share those 3 items

to the OP you are not likely to find a schematic .... only chance would be the manufacturer

Dave

EDIT: threads have been merged
 
Last edited:
Top