HP W22 Eliminate AC

[Akaister]

I would like to eliminate the AC power section and run DC voltage. I've replaced the CCFL's with LED's (12V DC). The conversion looks excellent. It would be a nice bonus if I could get rid of the AC board.
This is a HP W22 monitor ( I have three ), two more to fix.
I want to power the monitor from one AC/DC power brick. If it's not doable this is still a win.
Thanks for any guidance.

[Th3_uN1Qu3]

Re: HP W22 Eliminate AC

This monitor only uses 12v and 5v, so check the current consumption of the 5v supply and we'll see what can be done.

[Akaister]

Re: HP W22 Eliminate AC

Will do
Thank You

[Akaister]

Re: HP W22 Eliminate AC

5V is less than 1 watt (.7)
I measured one of the three 5V wires, they are common (same source). Is that correct?

[dumpystig]

Re: HP W22 Eliminate AC

Was your CCFL > LED conversion a kit or a custom mod by yourself? I'm wanting to convert a few Dell monitors that I have.

[tom66]

Re: HP W22 Eliminate AC

5V is less than 1 watt (.7)
I measured one of the three 5V wires, they are common (same source). Is that correct?

Not necessarily. You could measure the current through one wire, and disconnect the others. Only do this briefly as the wires are multiplied for a higher current rating.

When you say .7; do you mean 0.7 watts (140mA) or 700mA?

If the current consumption is only 140mA, then a 7805 on a small heatsink will be fine. It will dissipate 1W at 140mA, with 12V fixed input. You could bolt it to the LCD frame for good heatsinking. Remember to add some caps across the input and output for stability of the regulator; 330n or 470n each will be fine.

[Akaister]

Re: HP W22 Eliminate AC

tom66,
Yes, 140 ma @ 5V
Is there anything more than supplying 12/5Volt DC? I have a power supply brick with both voltages.
Thanks
dumpystig,
I bought 15 meters of smd 3528 led’s (600 led’s). I used 58 top and bottom 116 total. Lots of time spent gathering info, my concerns were color temp and light banding. I had a plan before I started and it worked out. I’m starting #2 and will be taking lots of pictures. It’s a easy project.
Led’s less than $6.00 per monitor, eBay.

[tom66]

Re: HP W22 Eliminate AC

tom66,
Yes, 140 ma @ 5V
Is there anything more than supplying 12/5Volt DC? I have a power supply brick with both voltages.
Thanks

A 7805 can produce 5V from a 12V input so you would only need 12V.

[Akaister]

Re: HP W22 Eliminate AC

tom66,
Success, I just removed the AC board, that felt real good. I used the 12V/5V brick, no problems.
This is only temporary, I’m going to use the 7805 you suggested. Looks like great solution for 5 volts. I really appreciate the help on this.
Thank you
Take Care

[tom66]

Re: HP W22 Eliminate AC

tom66,
Success, I just removed the AC board, that felt real good. I used the 12V/5V brick, no problems.
This is only temporary, I’m going to use the 7805 you suggested. Looks like great solution for 5 volts. I really appreciate the help on this.
Thank you
Take Care

Just remember to use a heatsink on the 7805 for maximum reliability.

Enjoy your LED monitor. I made an LED monitor too. My rather hastily made 15" LED monitor was made when I couldn't fix the CCFLs on a Dell 15". I used ready-made LED strips designed for 12V. As the monitor had an 18V power brick I used a 27 ohm 5W resistor and bolted that to the LCD panel as a heatsink, and a spare n-ch MOSFET (I had one in my junk bin... IRF510) to turn the LEDs on and off when the monitor switched on and off. The LEDs were surprisingly bright - more than bright enough to use, but I'd probably decrease the resistor in future.

[Akaister]

Re: HP W22 Eliminate AC

The finally tally on the 5V is 1300 ma. The 7805 limit is 1 Amp, I have several dual voltage bricks I can use. I know there are other regulators but I think this will work okay.
Keeping it simple, I hope.

[Scenic]

Re: HP W22 Eliminate AC

An ST-made 7805CV can supply up to 1.5A, but you probably have to get a bit creative in terms of heatsinking..

[tom66]

Re: HP W22 Eliminate AC

I've used one of these to repair an LCD TV before with a failed 5V supply on the motherboard: http://www.ebay.co.uk/itm/RC-3A-U-BE...item1e66108ed5

[PlainBill]

Re: HP W22 Eliminate AC

The finally tally on the 5V is 1300 ma. The 7805 limit is 1 Amp, I have several dual voltage bricks I can use. I know there are other regulators but I think this will work okay.
Keeping it simple, I hope.

I think you are going about it the wrong way. The original power supply put out 5V and probably 12V for the inverter. Remove the jumpers or cut the traces powering the inverter and use the 12V supply for the LEDs. If the inverter supply was over 12V, use a resistor or regulator to drop it to 12 volts.

PlainBill