Sceptre X20WG bad inveter board?

[Doitmyself]

I own a 2005 Sceptre X20WG. It started having problems recently, I would be computing when the monitor would flicker. Not fully on/off but it would become more dim temporarily. As this was happen I could hear the monitor make a buzzing noise that perfectly matched the flickering I was seeing. I could look through the back of the monitor as see/hear in the general area where I suspected the noise was coming from. Since then I unplugged the monitor and used a different one.

Well recently I disassembled the monitor and looked around in the area where I suspected the bad component was, this time I plug in the monitor (with the case open) and now it behaves differently. It will turn on and look fine for 5 seconds then go black, but the indicator light will still be on. I put my ear next to the 2 components that I suspected to be bad, I can still hear one of them make a small hum noise when the monitor is displaying then the humming stops when the screen goes black. The bad news is that the hum is so soft I can distinguish which component is the bad one.

The 2 components I suspect to be bad I took a close up picture of. I don't know for sure but I suspect one is an inductor and the other is a transformer.
The transformer (cube with yellow tape) has this written on it.
LF-002594-1
LI TAI 0545

I also looked over all of the capacitors on the suspected power board. None of them are bulging or leaking or burnt looking

Thanks for the help everyone

[jetadm123]

Re: Sceptre X20WG bad inveter board?

The flickering you describe sound more like bad/failing caps. Considering the monitor is approx 6 years old with the original caps, it might be due for a recap. I count 12 small caps that should be replaced. The two large 450V can be left alone. Replace with Panasonic FR, FM or FC series caps. You can order through digikey.com.

[POM_MJ]

Re: Sceptre X20WG bad inveter board?

I though, this problem caused by some bad CCFL due to leaked or broken.

if you have a known good CCFL, you can use it to substitute to find the bad CCFL on the panel.

[PlainBill]

Re: Sceptre X20WG bad inveter board?

I though, this problem caused by some bad CCFL due to leaked or broken.

if you have a known good CCFL, you can use it to substitute to find the bad CCFL on the panel.

You and jetadm123 are both correct. Either can be the cause. A shorted or open inverter transformer can also be the cause. And there are other possible causes.

PlainBill

[Doitmyself]

Re: Sceptre X20WG bad inveter board?

Thanks for the fast replies.

Jetadm123:
I am definitely open and willing to doing a recap of this board

POM_MJ:
I have never opened up the screen's steel casing to get a look at the CCFLs is this even possible or is it a lost cause if my CCFLs are bad?

PlainBill:
If it is possibly a shorted or open inverter transformer can I test it with a DMM or is it just something to try replacing? Is it possible to identify what the transformer specs are in order to buy a replacement?

Thanks

[alexanna]

Re: Sceptre X20WG bad inveter board?

Thanks for the fast replies.

I have never opened up the screen's steel casing to get a look at the CCFLs is this even possible or is it a lost cause if my CCFLs are bad?

Thanks

If it gets to the point where CCFLs are suspect and need to be ruled out.
There is no need to dissemble the LCD panel.
All you need to do is plug in other CCFLs into the monitor's inverter you're testing.
This could be done one CCFL at a time but it can take a long time.
I am fortunate that I have a lot of screens that have problems with the LCD itself, So it's as simple as plugging in another set of CCFLs and see if any thing changes.
I routinely use the bulbs from a 17” square monitor for testing and have had successful testing on screens up to 22” wide.

[PlainBill]

Re: Sceptre X20WG bad inveter board?

Thanks for the fast replies.

Jetadm123:
I am definitely open and willing to doing a recap of this board

POM_MJ:
I have never opened up the screen's steel casing to get a look at the CCFLs is this even possible or is it a lost cause if my CCFLs are bad?

PlainBill:
If it is possibly a shorted or open inverter transformer can I test it with a DMM or is it just something to try replacing? Is it possible to identify what the transformer specs are in order to buy a replacement?

Thanks

A quick and fairly reliable test is to measure the resistance of each secondary. They should match within 3%.

PlainBill