Samsung SyncMaster P2470H flickering

[sebr]

Hello,

I got a Samsung SyncMaster P2470H here with flickering backlight. Its turns on for a few seconds then of again an so on. If I turn on the display for the first time, picture is fine for a few seconds but then starts flickering. Also a hissing/whining sound can be heard from the inverter board which starts loud and then fades out. Besides that the display is functional, responds to keypress and even displays picture from all inputs.
This monitor doesn't have an internal PSU and is fed direct 14V from my lab PSU. There are only 5 electrolytic caps on the two boards inside which all tested fine. Also no loose connections, burnt components or arcing.
What would be the best point to start troubleshooting? I would say transformer or CCFL?

Regards

[retiredcaps]

Re: Samsung SyncMaster P2470H flickering

I would say transformer or CCFL?

I suggest testing both. The transformer is easy to test and only takes a couple of minutes.

As for the ccfl, look for burnt wiring.

Details for both are in the "2 seconds to black" guide below.

[sebr]

Re: Samsung SyncMaster P2470H flickering

Thanks for your advise. I removed the metal frame around the panel and traced the wiring but no burnt sport from arcing or anything else suspicious.

But transformer T4 caught my attention: I measured into each of the 4 lamp connectors and T1-T3 read 1,23k but T4 reads 1,28k. Then measuring between each of the 4 testpads on the secondary sides above the transformers and ground, T1-T3 read 0,93k while T4 was 0,99k.
Is T4 faulty?

[retiredcaps]

Re: Samsung SyncMaster P2470H flickering

T1-T3 read 0,93k while T4 was 0,99k.
Is T4 faulty?

The rule of the thumb, as I learned from PlainBill, is the transformers should be within 3% of each other. So yes, T4 is 6.45% (0.99 - 0.93/0.93) out of tolerance and suspicious.

I can't read the part number, but replacements may be available on ebay.

[sebr]

Re: Samsung SyncMaster P2470H flickering

Well the print on the transformer is:

N
GT-828
NY1009DB

that can be confirmed by the service manual (page 11):

BN81-04485A
A/S-TRANSFORMER;GT-828,燛FD1323
4
SNA

But unfortunately no luck at all on ebay to find some replacement

[retiredcaps]

Re: Samsung SyncMaster P2470H flickering

But unfortunately no luck at all on ebay to find some replacement

I don't know if it is worth it to you, but

http://www.ebay.com/itm/110904991655

is available for $38 USD. I can't vouch for the seller or if it even works.

You might want to see if they take back boards in case the transformer is not the problem.

[sebr]

Re: Samsung SyncMaster P2470H flickering

Yes i saw the whole inverter board too. But honestly this screen isn't worth it. Thanks anyways