HP 1740 LCD Monitor 2 seconds to black

[ntehicks]

I thought I would post this up here and ask if you think this would even be worth putting money into.
The monitor when turned on will come up to the normal screen for about 2 seconds and then you hear a noise like HV shorting out and then the monitor goes black. Every capacitor including the 450v 100uf is buldging. Infact this large capacitor has black gunk coming out of the front. With the monitor only a 17" and as you can see in the pictures many parts of the circuit board is really dark. Looks like this thing has some warmth going on inside

[PlainBill]

Re: HP 1740 LCD Monitor 2 seconds to black

It depends on what you feel your time is worth. Figure it will cost $12 -$15 for caps. If there is arcing at one of the CCFL leads a few drops of RTV or liquid electrical tape will fix that.

PlainBill

[George Ortiz]

Re: HP 1740 LCD Monitor 2 seconds to black

This looks like the same power supply problem areas that I had on my L1740 that I had to repair. I replaced the caps (got mine from Digi-key Look up my L1740 thread). Turns
out even after repairing the power supply the problem was that one set of CCFLs was burnt out. On another L1740 with the same power supply (this is a Phllips Power supply btw) problem, one set of CCFL's was burnt out. Definitely replace the bulging caps on the power supply and then check for the bad CCFL's.

[PlainBill]

Re: HP 1740 LCD Monitor 2 seconds to black

This looks like the same power supply problem areas that I had on my L1740 that I had to repair. I replaced the caps (got mine from Digi-key Look up my L1740 thread). Turns
out even after repairing the power supply the problem was that one set of CCFLs was burnt out. On another L1740 with the same power supply (this is a Phllips Power supply btw) problem, one set of CCFL's was burnt out. Definitely replace the bulging caps on the power supply and then check for the bad CCFL's.

George, how difficult was it to pull the CCFLs on your monitor? Would pulling them and examining them BEFORE replacing caps be practical?

Off the top of my head, the caps would cost $12 - $15. A working monitor would be worth $50 - $60, so there is a good return on investment. A pair of CCFLs would up the cost to over $35, making the project impractical, in my opinion.

PlainBill

[George Ortiz]

Re: HP 1740 LCD Monitor 2 seconds to black

If you have the power supply and logic board removed, disassembly of the lcd screen was not that hard. Also be carefull removing the lcd board that connects via mylar flat ribbon to the front of the lcd screen, I tore two when disaasembling the screen. I would definitely check the CCFL's first (with the Philips power supply board). There are two other companies that made the power supplies for this model of HP. Benq is one and the other I am not sure of. If ntehicks needs a repaired power supply/logic board combo, he can have one of mine. I have two of them sitting around. Just cover my shipping costs.

[bomcla]

Re: HP 1740 LCD Monitor 2 seconds to black

the pictures you posted, I thought I saw at least 3 swollen capacitors with the top (2 in the power supply board and a plate in the interface: If you did not already changed shall immediately, even if you have the opportunity to try the lamps is better. let us know!