I have a monitor Samsung P2470HD that I fixed, but I have no idea why my fix worked. Can anyone explain why did it work?
The monitor would power up and enable backlight only for a few seconds. Then it would continue to work and display image but the backlights would turn off.
I found a defective inverter transformer with one primary, two secondary windings. The secondaries measured ~1k and ~1.5k. I ordered a new one both secondaries of which measured ~1,07k.
However that fixed the issue for exactly one turn on. After I powered it off and on it would have the original fault. The transformer tested OK. I did several other tests, re-soldered a few CCFL connections etc to no avail.
The inverter seemed to light other known-good CCFLs just fine. The "defective" CCFLs would work with an inverter from another monitor (Samsung 19") fine as well. So... what could be the problem?!
Back to working only with the defective monitor. I then tried swapping CCFL connections in random patterns. The combination that I found "fixed" the monitor but left me puzzled as to why it works.
Here's what I've done:
1 & 2 connect to bottom CCFLs
3 & 4 connect to top CCFLs
If I interchange 1 and 2 - backlights shut off
If I swap between 3 and 4 - backlights turn off still
However, if I swap 1 and 3 (or 2 and 4) - CCFLs start up and work fine.
The question is - why would this work?
The monitor would power up and enable backlight only for a few seconds. Then it would continue to work and display image but the backlights would turn off.
I found a defective inverter transformer with one primary, two secondary windings. The secondaries measured ~1k and ~1.5k. I ordered a new one both secondaries of which measured ~1,07k.
However that fixed the issue for exactly one turn on. After I powered it off and on it would have the original fault. The transformer tested OK. I did several other tests, re-soldered a few CCFL connections etc to no avail.
The inverter seemed to light other known-good CCFLs just fine. The "defective" CCFLs would work with an inverter from another monitor (Samsung 19") fine as well. So... what could be the problem?!
Back to working only with the defective monitor. I then tried swapping CCFL connections in random patterns. The combination that I found "fixed" the monitor but left me puzzled as to why it works.
Here's what I've done:
1 & 2 connect to bottom CCFLs
3 & 4 connect to top CCFLs
If I interchange 1 and 2 - backlights shut off
If I swap between 3 and 4 - backlights turn off still
However, if I swap 1 and 3 (or 2 and 4) - CCFLs start up and work fine.
The question is - why would this work?
