A plea for help repairing a PC monitor

  • Thread starter Thread starter Norman Morton
  • Start date Start date
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Norman Morton

Hello! Can anyone help me please?

Is there anyone who can download for me a copy of the circuit diagram for
the Main board in a IIyama PC Monitor type MT 9017T (Vision Master Pro 17).

I have a fault that is driving me mad. When the computer is first
switched-on a vertical line appears down the centre of the monitor screen.
If a small transformer it tapped after windows XP has finished loading (so
the screen is not in 'black' mode), the screen becomes normal and stays
normal all the time the computer is on. I have removed the main board and
looked for bad joints and cracked tracks and have even taken the transformer
out and checked the wire termination joints. One oddity of the transformer
is that when the resistance of the windings is checked with an ohmmeter
(1.5v cell), on one of the windings a spark occurs when the probe of the
meter completes the circuit and a reading of 0.033 ohms is recorded. The
wire gauge of the windings looks substantial. I think this transformer must
be something to do with the horizontal line scan circuitry. Obviously there
is EHT to the tube so the line transformer must be driven somehow unless the
EHT is generated some another way.

Thank you

Regards

Norman Morton
 
Norman said:
Hello! Can anyone help me please?

Is there anyone who can download for me a copy of the circuit diagram for
the Main board in a IIyama PC Monitor type MT 9017T (Vision Master Pro 17).

I have a fault that is driving me mad. When the computer is first
switched-on a vertical line appears down the centre of the monitor screen.
If a small transformer it tapped after windows XP has finished loading (so
the screen is not in 'black' mode), the screen becomes normal and stays
normal all the time the computer is on. I have removed the main board and
looked for bad joints and cracked tracks and have even taken the transformer
out and checked the wire termination joints.
Click to expand...
Your problem is most likely a poor connection somewhere in the
horizontal drive circuit. I doubt however that the problem is in the
transformer you removed, but that the transformer is simply moving the
PWB when hit.
One oddity of the transformer
is that when the resistance of the windings is checked with an ohmmeter
(1.5v cell), on one of the windings a spark occurs when the probe of the
meter completes the circuit and a reading of 0.033 ohms is recorded. The
wire gauge of the windings looks substantial. I think this transformer must
be something to do with the horizontal line scan circuitry.
Click to expand...
There is a drive transformer for the HOT and that might be what you are
striking. To determine where the fault lies, one almost needs a scope
to observe the horizontal drive signal and a DVM to see if the B+ is
present for the HOT. I would put the transformer back in and look for a
poor solder connection. Sometimes they are not easily seen, but
guessing at a component without having a measurement to give you cause
to believe it is bad is a tough way to go!
Obviously there
is EHT to the tube so the line transformer must be driven somehow unless the
EHT is generated some another way.
Click to expand...
Some monitors derive their HV not from the drive for the horizontal
sweep, but by a separate semiconductor and winding on the flyback. The
fact that you have HV does not mean that you have horizontal sweep.
Thank you

Regards

Norman Morton
Click to expand...
Ken
 
Hello! Can anyone help me please?

Is there anyone who can download for me a copy of the circuit diagram for
the Main board in a IIyama PC Monitor type MT 9017T (Vision Master Pro 17).
Click to expand...
<snip>

Before you kill yourself take the monitor to a TV repair specialist.

Remember this phrase "A little knowledge is a dangerous thing".



--
________________________
Conor Turton
(e-mail address removed)
ICQ:31909763
________________________
 
I used to work for a TV shop , we never worked on comp monitors though
and I did not know that
drawings/schematics/service-literature/circuit-diagrams was available
for comp monitors , much less parts ( from the manufacturer ) . HV is
very dangerous though , and the currents in a color tv can KILL VERY
EASILY!!!

tim
 
I used to work for a TV shop , we never worked on comp monitors though
and I did not know that
drawings/schematics/service-literature/circuit-diagrams was available
for comp monitors , much less parts ( from the manufacturer ) . HV is
very dangerous though , and the currents in a color tv can KILL VERY
EASILY!!!
Click to expand...
Don't know about the US but in the UK there are plenty of TV repair
shops that'll do monitors.
I have a friend who repairs TVs. I'm a qualified electronics engineer
but I still take them to him because to me it seems to be some kind fo
black art especially where the HT side of things starts to be involved.
Sure you can apply the fundamentals to it but fault finding on them
seems to be a bit of an acquired skill.


--
________________________
Conor Turton
(e-mail address removed)
ICQ:31909763
________________________
 
--
Remove "SPAM" to reply.
Norman Morton said:
Hello! Can anyone help me please?

Is there anyone who can download for me a copy of the circuit diagram for
the Main board in a IIyama PC Monitor type MT 9017T (Vision Master Pro 17).

I have a fault that is driving me mad. When the computer is first
switched-on a vertical line appears down the centre of the monitor screen.
If a small transformer it tapped after windows XP has finished loading (so
the screen is not in 'black' mode), the screen becomes normal and stays
normal all the time the computer is on. I have removed the main board and
looked for bad joints and cracked tracks and have even taken the transformer
out and checked the wire termination joints. One oddity of the transformer
is that when the resistance of the windings is checked with an ohmmeter
(1.5v cell), on one of the windings a spark occurs when the probe of the
meter completes the circuit and a reading of 0.033 ohms is recorded. The
wire gauge of the windings looks substantial. I think this transformer must
be something to do with the horizontal line scan circuitry. Obviously there
is EHT to the tube so the line transformer must be driven somehow unless the
EHT is generated some another way.

Thank you

Regards

Norman Morton
Click to expand...

Wouldn't it would be easier to buy a new monitor for $149
 
Hello! Can anyone help me please?

Is there anyone who can download for me a copy of the circuit diagram
for the Main board in a IIyama PC Monitor type MT 9017T (Vision Master
Pro 17).

I have a fault that is driving me mad. When the computer is first
switched-on a vertical line appears down the centre of the monitor
screen. If a small transformer it tapped after windows XP has finished
loading (so the screen is not in 'black' mode), the screen becomes
normal and stays normal all the time the computer is on. I have
removed the main board and looked for bad joints and cracked tracks
and have even taken the transformer out and checked the wire
termination joints. One oddity of the transformer is that when the
resistance of the windings is checked with an ohmmeter (1.5v cell), on
one of the windings a spark occurs when the probe of the meter
completes the circuit and a reading of 0.033 ohms is recorded. The
wire gauge of the windings looks substantial. I think this transformer
must be something to do with the horizontal line scan circuitry.
Obviously there is EHT to the tube so the line transformer must be
driven somehow unless the EHT is generated some another way.

Thank you

Regards

Norman Morton
Click to expand...

Now this point I agree on Take it to a repair shop
if you are not familyer with the HV of HOT and HV
you could get HURT or Evan Killed.

Just my Two cents Gunner
 
sounds like you have lost horizontal deflection. does your monitor have relays
to adjust screen resolution? perhaps the contacts are corroded. check your
leads and such leading to the deflection coils on the neck of the tube. and
like the other response said, be very very careful of the high voltage. the
wire that leads to the side of the pic tube with the suction cup has about
25,000 volts on it. and it stays charged in the pic tube long after you turn it
off.
 
Now this point I agree on Take it to a repair shop
if you are not familyer with the HV of HOT and HV
you could get HURT or Evan Killed.
Click to expand...

Just make sure Evan doesn't start playing inside the monitor and he'll be
fine!
 
You might try the newsgroup sci.electronics.repair
There are a bunch of folks out there that should be able to help you. I
might suggest too, that you look for a cold solder joint. Most of these
devices are on single sided boards and the only thing that makes a
connection to the foil is the solder filet, which many times is next to
nothing.
Good luck....Ross
 
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