Hi. Just got a Digimate 17 inch monitor with no display. Found a bad
shottky diode on the inverter PCB so I replaced that and the fuse, now I
have a screen, however after a few minutes it starts to flicker badly,
on the inverter the transformer on the side I replaced the diode is
getting hot. After a bit of tracing I have found a small SMD (8 pin,
looks like an IC) which is shorted to all pins. I am unable to read the
tiny writing on top and can find no information on what the part is.
Does anyone have any idea, or possibly a schematic. Judging by the way
it is connected (there is an identical one on the other side of the
inverter, dual lamp) I think it may actually be a special kind of zener
diode.

Anyway some numbers, the monitor is a Digimate L-1715 ( I believe the
inverter is used in a variety of other brands ). The inverter PCB is
part number IV185030HX. The part I need is identified as Q3 (maybe a
transistor?)

Can anyone help?

On Fri, 27 Aug 2010 07:56:07 +0100, Clyde
wrote:

Hi. Just got a Digimate 17 inch monitor with no display. Found a bad
shottky diode on the inverter PCB so I replaced that and the fuse, now I
have a screen, however after a few minutes it starts to flicker badly,
on the inverter the transformer on the side I replaced the diode is
getting hot. After a bit of tracing I have found a small SMD (8 pin,
looks like an IC) which is shorted to all pins. I am unable to read the
tiny writing on top and can find no information on what the part is.
Does anyone have any idea, or possibly a schematic. Judging by the way
it is connected (there is an identical one on the other side of the
inverter, dual lamp) I think it may actually be a special kind of zener
diode.

Anyway some numbers, the monitor is a Digimate L-1715 ( I believe the
inverter is used in a variety of other brands ). The inverter PCB is
part number IV185030HX. The part I need is identified as Q3 (maybe a
transistor?)

Best idea is to post this on www.badcaps.net as there are quite a
number of very experienced LCD monitor repair types lurking there.
And read the "how to post pics" advice first, to stay on the right
side of them ;-)

On Fri, 27 Aug 2010 07:56:07 +0100, Clyde
put finger to keyboard and
composed:

Hi. Just got a Digimate 17 inch monitor with no display. Found a bad
shottky diode on the inverter PCB so I replaced that and the fuse, now I
have a screen, however after a few minutes it starts to flicker badly,
on the inverter the transformer on the side I replaced the diode is
getting hot. After a bit of tracing I have found a small SMD (8 pin,
looks like an IC) which is shorted to all pins. I am unable to read the
tiny writing on top and can find no information on what the part is.
Does anyone have any idea, or possibly a schematic. Judging by the way
it is connected (there is an identical one on the other side of the
inverter, dual lamp) I think it may actually be a special kind of zener
diode.

Anyway some numbers, the monitor is a Digimate L-1715 ( I believe the
inverter is used in a variety of other brands ). The inverter PCB is
part number IV185030HX. The part I need is identified as Q3 (maybe a
transistor?)

Can anyone help?

I'm confused. At one point you say the mystery device is a special
zener diode, then you go on to say that it is a transistor. Are you
talking about two different components?

IME, 8-pin smd transistors are often MOSFETs. There is usually one
gate pin, and several drain and source pins.

Is there a control IC on the inverter board? If so, then its datasheet
may have an application circuit that is similar to yours.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On 28/08/2010 09:07, Franc Zabkar wrote:
On Fri, 27 Aug 2010 07:56:07 +0100, Clyde
put finger to keyboard and
composed:

Hi. Just got a Digimate 17 inch monitor with no display. Found a bad
shottky diode on the inverter PCB so I replaced that and the fuse, now I
have a screen, however after a few minutes it starts to flicker badly,
on the inverter the transformer on the side I replaced the diode is
getting hot. After a bit of tracing I have found a small SMD (8 pin,
looks like an IC) which is shorted to all pins. I am unable to read the
tiny writing on top and can find no information on what the part is.
Does anyone have any idea, or possibly a schematic. Judging by the way
it is connected (there is an identical one on the other side of the
inverter, dual lamp) I think it may actually be a special kind of zener
diode.

Anyway some numbers, the monitor is a Digimate L-1715 ( I believe the
inverter is used in a variety of other brands ). The inverter PCB is
part number IV185030HX. The part I need is identified as Q3 (maybe a
transistor?)

Can anyone help?

I'm confused. At one point you say the mystery device is a special
zener diode, then you go on to say that it is a transistor. Are you
talking about two different components?

IME, 8-pin smd transistors are often MOSFETs. There is usually one
gate pin, and several drain and source pins.

Is there a control IC on the inverter board? If so, then its datasheet
may have an application circuit that is similar to yours.

- Franc Zabkar

Sorry, the only letter I could read on the top was "N" which when I
checked online mentioned a zener diode. However it is labeled Q3 which
suggests otherwise. I have since found out it is an N channel MOSFET. It
does have 3 pins tied on one side, 4 on the other and a single pin. It
is short-circuit to all pins.