Need help with Capacitor Swap

[snatr]

Hi. I'm working on an LCD television that I think has a bad capacitor.

My question is... Would I be ok replacing a 10 pf 3 KV with a 12 pf 3 KV capacitor?
I know there is some playroom when it comes to capacitors; and I'm swapping up, but that's a pretty big difference.

I would really appreciate any advice. Thanks!

 

[Resqueline]

I guess that cap sits in series with the output of the ccfl backligt driver. I've seen a pair of burnt caps there once.
These caps are used just like inductor ballasts are used in fluorescent lamps.
I don't think the 20% increase will affect the operation much (if any) as the circuit also has current sensing resistors that it uses to regulate the tube current (within milliseconds).

 

[snatr]

Capacitor Result

I replaced the capacitor but it didn't solve the problem I was having. I think it's a voltage problem altogether.

As far as replacing the capacitor. The only ill effect that I seemed to get, was some interference through one of the video inputs.

 

[Resqueline]

Often there's a surface mount fuse on such inverter boards. Is it completely dark?

 

[davenn]

I replaced the capacitor but it didn't solve the problem I was having. I think it's a voltage problem altogether.

As far as replacing the capacitor. The only ill effect that I seemed to get, was some interference through one of the video inputs.

What are the symptoms of the fault ? is the monitor totally dead ? is the power on LED
briefly green then going to red ... contineous or flashing?
if its not totally dead is it displaying OSD ie the monitor menu ??

As I have just stated in another message on the forum .... electrolytic capacitors are the
most common source of failure....
check for any for bulging tops and replace ... I fix 95% of computer and general LCD
monitors by replacing faulty electro's

Some monitors have a small separate HV supply board for supplying the backlight fluro's
check for 12V going to that board from the main board (if that is what you have there)
There are often 1 or 2 small electros ~ 100 - 220uF at 25V on that board that dry out


cheers
Dave
VK2TDN