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LCD Inverter Repair

chiefnicholls

Mar 18, 2009
1
Joined
Mar 18, 2009
Messages
1
I am working on a LCD computer monitor. It destroyed a polystyrene block shaped capacitor on the low voltage side of the flourescent tube display power board.

The cap (I believe .1mfd) was between the two switching transtiors that power the step-up transformer.

I thought this was a cap to supress "ringing" in the circuit. The original was melted, so I used a 250 volt .1. It bulged, and failed.

No schematic, but this is similar to many others. That is why In used a .1 ufd.

Any thoughts? I realize the transformer might have a bad winding, but I might have the cap value wrong.

Thanx. Gary
 

mrdoodad

Aug 24, 2009
3
Joined
Aug 24, 2009
Messages
3
Cap problem on LCD power board

I am working on a LCD computer monitor. It destroyed a polystyrene block shaped capacitor on the low voltage side of the flourescent tube display power board.

The cap (I believe .1mfd) was between the two switching transtiors that power the step-up transformer.

I thought this was a cap to supress "ringing" in the circuit. The original was melted, so I used a 250 volt .1. It bulged, and failed.

No schematic, but this is similar to many others. That is why In used a .1 ufd.

Any thoughts? I realize the transformer might have a bad winding, but I might have the cap value wrong.

Thanx. Gary



Gary,

The cap is probably a 1000V rating, and you need to check (with meter, monitor off) the transistors for shorts. See if any suppression diodes (may have a BZ**** number) are burned up--circuit may have sustained a lightning strike..

DP
 
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