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From: T Marshall on 14 Apr 2010 06:25
Hi
Can anyone help with schematics of power board for above Monitor.
I have got schematics for X233H but this X233H b is completely different.
Uses a TL494 IC.

The problem is,the two fluorescents only briefly light twice.

Many thanks
From: T Marshall on 14 Apr 2010 09:57
Meat Plow wrote:
> On Wed, 14 Apr 2010 11:25:23 +0100, T Marshall
> <tommy-krihc(a)tiscali.co.uk>wrote:
>
>> Hi
>> Can anyone help with schematics of power board for above Monitor.
>> I have got schematics for X233H but this X233H b is completely different.
>> Uses a TL494 IC.
>>
>> The problem is,the two fluorescents only briefly light twice.
>>
>> Many thanks
>
> I would be looking more at the inverter or maybe one of the
> fluorescent's being bad than the PSU unless you've verified
> the PSU is bonked somehow.
thanks for reply. Its the inverter and control section I am trying to
check. Every thing else seems to be ok. It did fire up once and display
picture OK. looking for circuit to see if I can inhibit error detection
Tommy
From: who where on 14 Apr 2010 20:30
On Wed, 14 Apr 2010 14:57:36 +0100, T Marshall
<tommy-krihc(a)tiscali.co.uk> wrote:

>Meat Plow wrote:
>> On Wed, 14 Apr 2010 11:25:23 +0100, T Marshall
>> <tommy-krihc(a)tiscali.co.uk>wrote:
>>
>>> Hi
>>> Can anyone help with schematics of power board for above Monitor.
>>> I have got schematics for X233H but this X233H b is completely different.
>>> Uses a TL494 IC.
>>>
>>> The problem is,the two fluorescents only briefly light twice.
>>>
>>> Many thanks
>>
>> I would be looking more at the inverter or maybe one of the
>> fluorescent's being bad than the PSU unless you've verified
>> the PSU is bonked somehow.
>thanks for reply. Its the inverter and control section I am trying to
>check. Every thing else seems to be ok. It did fire up once and display
>picture OK. looking for circuit to see if I can inhibit error detection

The main switcher and the inverter monitoring are totally separate on
every LCD monitor I have worked on. The backlights are fired at full
brightness, then the current feedback circuit kicks in to achieve the
preset level. If the monitoring chip detects an imbalance between the
2 (3) tube drivers it shuts them down.

Best suggestion: get onto badcaps.net and usually someone there will
steer you through this. Circuits are rarely required.
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