Hi,
I'm trying to bring an HP-2338h widescreen monitor back to life. It had the two seconds to black problem. All power supply caps check good for ESR and value.
It looks like there is some kind of substance around the lower set of ccfl lamps, maybe phosphor powder? The monitor has two lamps on the top edge and two on the bottom. I can plug two test ccfl bulbs (from a computer light kit) into the lower set of sockets and all bulbs light. The test bulbs are about 300 mm long while the original bulbs are 2.4 mm diameter and 525 mm long. I ordered two bulbs from ccfl warehouse and the new bulbs won't light when used with the original two. I can light the new bulbs with the inverter that came with the light kit but I notice I have to increase the voltage on my power supply and the current is higher than with my shorter test lamps.
My questions are these. Do you think that the circuit is sensing the two different currents between the bottom and top bulbs and shutting down? Will buying two more bulbs of the same kind solve the turn on prolem? Do these inverter circuits on the power supply typically have enough range in the voltage and current to light a wider range of bulb specs?
The only numbers on the power supply I could find are 715G2824-1-7 and on a tag on the solder side of the board 8EA42SQWP. The monitor was built in 2009.
Thanks,
Mike
I'm trying to bring an HP-2338h widescreen monitor back to life. It had the two seconds to black problem. All power supply caps check good for ESR and value.
It looks like there is some kind of substance around the lower set of ccfl lamps, maybe phosphor powder? The monitor has two lamps on the top edge and two on the bottom. I can plug two test ccfl bulbs (from a computer light kit) into the lower set of sockets and all bulbs light. The test bulbs are about 300 mm long while the original bulbs are 2.4 mm diameter and 525 mm long. I ordered two bulbs from ccfl warehouse and the new bulbs won't light when used with the original two. I can light the new bulbs with the inverter that came with the light kit but I notice I have to increase the voltage on my power supply and the current is higher than with my shorter test lamps.
My questions are these. Do you think that the circuit is sensing the two different currents between the bottom and top bulbs and shutting down? Will buying two more bulbs of the same kind solve the turn on prolem? Do these inverter circuits on the power supply typically have enough range in the voltage and current to light a wider range of bulb specs?
The only numbers on the power supply I could find are 715G2824-1-7 and on a tag on the solder side of the board 8EA42SQWP. The monitor was built in 2009.
Thanks,
Mike
But today, I’m making an exception here. Why? No idea. Perhaps only because the repair details are still “fresh” in my head… which is ironic, given this is a 16 year old monitor that hardly anyone will care about today. It is new to me, though. 
I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
