Re: HP L1940t turns on and off frequently

Hello all,

Not to sound like things are hopeless I repaired four of these. I ended up replacing the power board on two of the four only to have one of the new power boards fail. As a tech I feel a backlight is failing(one or more) and the negative feedback (HVAC) causes the C5707 transistors to fail. Also when replacing the C5707 transistors replace the two FET's (replace all six transistors). When you power the unit keep the back covers off and listen for noise, if you hear a high pitch squeal while the power is off...

Re: Hp 1940 flicker

All,

I have this issue/repairing for my friend. I am an old school technician and can tell you to change all C5707 transistors and the two Field Effect Transistors near the ballast transformers. You may also need to change the dual schottky diodes (two transistors mounted on the heat sink). The flicker is on and off due to improper regulation on the ballast side. I have four of these to repair/this is the second time because I did not change the FET's. I currently have one on "Burn in" for 24hrs. Email me if you need any addiditonal...