The blog of a Leslie Wong
I’ve been getting some comments on my HP f1703 flat panel display fix. Yesterday on Instructables, leevonk posted Repair a Flatscreen Monitor for $15. This is a good (non-specific manufacturer) tutorial on actually replacing the inverters and backlights.
Remember, even if the backlight isn’t working, you should still be able to see an image on the display in bright light (e.g., you should be able to see a boot screen or your cursor move) if the rest of the display is working correctly.
Disclaimer:
DO THIS AT YOUR OWN RISK!
I am not responsible for any damage you might cause to your monitor or yourself by following these instructions. If you open up your monitor case to this point, you will probably void your warranty.
CAUTION: There may be HIGH VOLTAGE present. Disconnect all power during disassembly. Inverters can generate high voltages.
If this repair is too daunting, HP has offered an extended warranty in this HP Support document. Thank you, tsmitty, for this link to HP Support. (Jan. 23, 2009: HP has discontinued this offer)
My HP Pavilion f1703 LCD Monitor suffered the same blackout symptoms as other posters in the CNET forum. After powering on, the display would go black after a few seconds. It was not the power supply in my case – I tried another working power supply with the same result.
It was also not a software problem, e.g., XP SP2, power management, screensavers, etc. In my case, it was a hardware problem, as I tried the monitor on a different machine with the same result: power on, brief display, then black. It also exhibited this behavior with no cable connected to the monitor.
I noticed the screen was faintly visible under bright light and realized that the backlight was not working. It seemed unlikely that the fluorescent tube would fail – I have had my Toshiba Portege 7200CT notebook computer on for 5 years, running SETI@Home.
Since the monitor was out of warranty, I decided to try to repair it myself. This is not a step-by-step procedure, but an general overview of how I solved MY problem with this monitor.
After reading the posts, it seemed that there must have been a loose connection on the circuit board that drives the monitor’s backlight. I especially noted gromit588’s post about disassembly and followed the instructions. gromit588’s experience must have shorted some connection closed to fix the problem. I found that it did not help me, so I looked for bad (cold) solder joints on the backlight inverter board.
After a close inspection of the board, the bad solder joint was obvious. The bad solder joint on my board was on one of the coils – the bare pin on the coil was sticking through from the component side with very little solder on the pad on the circuit board. I resoldered it and that fixed the problem. There may be other cold solder joints at different locations on YOUR board. You just have to inspect each joint carefully.
Close-up of the backlight inverter board with the repaired cold solder joint circled. Inspect the board for cold solder joints – they will be fairly obvious. It’s possible that the cold solder joints on YOUR board are in different locations on the board from the one circled here: (Jan. 23, 2009: If the cold joints aren’t obvious, I recommend using a 10x magnifier, or just reheat the solder joints on the components that have white glue holding them to the circuit board, see fig. 2)
