Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Kipmans
 
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Default LG Studioworks 520Si monitor; doesn't power up after disconnected the deflection coils

Hello,

I have a bit of a problem with a LG Studioworks 520Si CRT monitor. I got
it today and powered it up, but with no computer or whatsoever attached.
Everything seemed to be working fine. The next thing I did (my reasons are
unimportant ;-)) was disconnecting the four wires which connect the 2
deflection coils to the big circuit board of the monitor. When I tried to
turn it on, the monitor began producing a sort of a 'beep' sound, which
repeats itself very quickly (until I pulled the plug :-)). Also, the LEDs
on the front except for the power LED are blinking in the same 'rhythm'. I
disconnected the power cable and plugged the 4 wires back in, but the
problem persists.

I took a look at the board, but I don't see any damaged parts. Has anyone
an idea on how I can solve this, or did I just destroy a good monitor
(hopefully not :-)).

Thanks in advance.

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Kipmans wrote:
I have a bit of a problem with a LG Studioworks 520Si CRT monitor. I got
it today and powered it up, but with no computer or whatsoever attached.
Everything seemed to be working fine. The next thing I did (my reasons are
unimportant ;-)) was disconnecting the four wires which connect the 2
deflection coils to the big circuit board of the monitor. When I tried to
turn it on, the monitor began producing a sort of a 'beep' sound, which
repeats itself very quickly (until I pulled the plug :-)). Also, the LEDs
on the front except for the power LED are blinking in the same 'rhythm'. I
disconnected the power cable and plugged the 4 wires back in, but the
problem persists.
I took a look at the board, but I don't see any damaged parts. Has anyone
an idea on how I can solve this, or did I just destroy a good monitor
(hopefully not :-)).


You probably blew the horizontal output transistor, possibly some
related parts along with it. Never randomly pull connectors unless you
want to sabotage the equipment.


Met vriendelijke groet,

Maarten Bakker.
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Graham
 
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Default



"Kipmans" wrote in message
news
Hello,

I have a bit of a problem with a LG Studioworks 520Si CRT monitor. I got
it today and powered it up, but with no computer or whatsoever attached.
Everything seemed to be working fine. The next thing I did (my reasons are
unimportant ;-)) was disconnecting the four wires which connect the 2
deflection coils to the big circuit board of the monitor. When I tried to
turn it on, the monitor began producing a sort of a 'beep' sound, which
repeats itself very quickly (until I pulled the plug :-)). Also, the LEDs
on the front except for the power LED are blinking in the same 'rhythm'. I
disconnected the power cable and plugged the 4 wires back in, but the
problem persists.

I took a look at the board, but I don't see any damaged parts. Has anyone
an idea on how I can solve this, or did I just destroy a good monitor
(hopefully not :-)).

Thanks in advance.



Reminds me of a job I was asked to do many years ago at the local TV studio.
I had to modify two CTV's so that the picture was the right way when the
sets were suspended upside down from the ceiling . Can't recall why they had
to do it that way.

As the other poster said, the HOT is probably short, It's the power
transistor on a heatsink near the flyback transformer.

--
Graham.



%Profound_observation%


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Kipmans
 
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Default

Ok, I'm going to see if I can get another transistor of the same type and
check if it works when I replace the old one. Another question, would it
damaged the monitor if I'd ran it with only the vertical deflection coil
detached?

On Tue, 30 Aug 2005 22:31:51 +0200,
maarten wrote:

Kipmans wrote:
I have a bit of a problem with a LG Studioworks 520Si CRT monitor. I got
it today and powered it up, but with no computer or whatsoever attached.
Everything seemed to be working fine. The next thing I did (my reasons are
unimportant ;-)) was disconnecting the four wires which connect the 2
deflection coils to the big circuit board of the monitor. When I tried to
turn it on, the monitor began producing a sort of a 'beep' sound, which
repeats itself very quickly (until I pulled the plug :-)). Also, the LEDs
on the front except for the power LED are blinking in the same 'rhythm'. I
disconnected the power cable and plugged the 4 wires back in, but the
problem persists.
I took a look at the board, but I don't see any damaged parts. Has anyone
an idea on how I can solve this, or did I just destroy a good monitor
(hopefully not :-)).


You probably blew the horizontal output transistor, possibly some
related parts along with it. Never randomly pull connectors unless you
want to sabotage the equipment.


Met vriendelijke groet,

Maarten Bakker.


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