H.P. L1710 back lamps turning off

[alexanna]

Re: H.P. L1710 back lamps turning off

I wonder if my problem may be trying to use a voltage regulator that has been salvaged from another board, I just replaced the 1117 3.3v regulator with a used one and I get a good green power light for about 5 or 6 seconds with a good 3.3v and the it turns amber, back lights are still staying on but the v out of the 3.3v regulator goes down to 1.6 volts ,It is also very Hot to the touch.If the regulator states it's 3.3v I am guessing a resistor is not involved?
Al.

[PlainBill]

Re: H.P. L1710 back lamps turning off

I realy think it is a oz5936gn,I will get my wife to help verify
she has better eyes than I do.Thanks for the effort but this damm thing has devloped some other issues.I will try to explain in my next post.
Al

Except that OZ5936 is not a legitimate part number. Even the surplus IC sellers don't claim to have it on hand.

PlainBill

[PlainBill]

Re: H.P. L1710 back lamps turning off

I wonder if my problem may be trying to use a voltage regulator that has been salvaged from another board, I just replaced the 1117 3.3v regulator with a used one and I get a good green power light for about 5 or 6 seconds with a good 3.3v and the it turns amber, back lights are still staying on but the v out of the 3.3v regulator goes down to 1.6 volts ,It is also very Hot to the touch.If the regulator states it's 3.3v I am guessing a resistor is not involved?
Al.

Yes.

PlainBill

[alexanna]

Re: H.P. L1710 back lamps turning off

Yes.

PlainBill

Using the used part, or no resistor?
Al.

[PlainBill]

Re: H.P. L1710 back lamps turning off

Using the used part, or no resistor?
Al.

No, the used part was not the problem. Yes, there is no resistor.

PlainBill

[alexanna]

Re: H.P. L1710 back lamps turning off

Well it's time to call it quits on this one.
For some reason on the 3.3v regulator pads the ground pad has become shorted to the v out pad, I guess that explains the hot to the touch and failing regulator. I cannot see anything thing obvious on the surface of the logic board and it's only the 3.3v regulator that shows shorted to ground, the 1.8v pads are ok.
Al.

[micoman]

Re: H.P. L1710 back lamps turning off

dear friend. I have 3 x monitors LCD HP L1710, I want clean inside because drop water, but I can´t remove the back cover. I remove four screws. But How I remove the back cover to access inside the monitor.??
Thanks for your help

I have a H.P. L 1740 that after about 20 minutes the back lights are going off, And a image is visible.
The B.L. on signal is not changing when the lamps go off, I have traced the signal down to the green card between the two ccfl transformers and it is good.
With the monitor dissembled it takes much longer for the lamps to turn off upwards of 2 hours or more.
I am seeing 12.5v across the inverter caps when the lamps or on and aprox.13v when the lamps are not on.
I have measured the A.C. voltage on the return lines of the ccfls when the lamps are on.
#3 is between 1.18 and 1.25 vac as measured with min. max
#4 is 1.42 to 1.58 vac
#1 is 1.70 to 1.89 vac
And #2 is 1.14 to 1.20 vac
I have tried the measurements with two different panels and voltages are very similar on the return lines.I really haven't checked voltages on the return lines enough to know if there is too much of a difference in the voltages on the return lines? I am thinking about poor solder joints in the inverter area. When I can get this to fail again is there anything else that I could check to narrow down the problem?
U1 is an oz59360n. The two other 8 leg chips are 9971gm mosfets.
Al.

[alexanna]

Re: H.P. L1710 back lamps turning off

dear friend. I have 3 x monitors LCD HP L1710, I want clean inside because drop water, but I can´t remove the back cover. I remove four screws. But How I remove the back cover to access inside the monitor.??
Thanks for your help

Remove the front cover first.The LCD and it's and power supply are cliped to the back cover.You would have to pry it out.