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.
This is a view of the monitor disassembled from the case:
This is the component side of the backlight inverter board:
This is the solder side of the backlight inverter board with the bad joint circled:
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)
About.me
Gastropoda
leapingmonkeys
The Onion
Toolmonger
January 14th, 2012 at 4:44 PM
I have the f1703 and my power board is completly different what do i do
October 20th, 2011 at 2:55 PM
RE: HP f1503 lcd monitor
Hi everyone,
can someone help me identify a fried resistor on the board
it is located at R128… many thanks in advance
June 10th, 2011 at 4:15 AM
i have viwsonic monitor pls helpe me fault my monitor monitor on few minut after brightness show pls mail me.
October 5th, 2010 at 4:48 PM
Leslie,
stays on indefinitely and I am now using an original HP 12v supply.
If I unplug it, it turns off immediately.
I still believe I have a bridged track or component as 2 of the solder pads and tracks lifted when I was removing those inverter transistors. This perhaps why I have a current leak…
May have to de-solder and try again…
October 5th, 2010 at 11:05 AM
Todd, does it go off after a while or does it always on? What happens if you unplug it? Could it be some residual voltage because of your 18V power supply?
October 5th, 2010 at 2:54 AM
Well, I replaced the 4 Inverter Transistors today, and voila it works. However…
…when I turn it off, the yellow light goes out, but the top right hand side of the screen stays lit?? I have looked at the board and cannot ‘see’ any bridged tracks…any suggestions?
October 4th, 2010 at 4:41 PM
Leslie,
I have been running this power supply on the f1503 now for about 2 years, I opened it up last week and had a look, nothing is showing signs of running too hot, but you are right it is probably a ticking bomb and will eventually fail.
I have found another f1703 at my local auctioneer and hopefully will win that one for $10 Aussie – it powers on but no picture, sounds like the inverter board. Hopefully the joints on the toroid coils are dry or a few bad caps, nevertheless I now have 2 of these monitors to work on both for under AU $25…with parts and power supplies.
Thanks for the help.
September 28th, 2010 at 8:04 AM
(continuing the story from post 344)
The monitor has been functioning since May. Some weeks ago, the kids started to complain about having to use the on/off button repeatedly before the monitor would stay on, and finally it would not switch on any more. My wife has bought them a new one, but after some trial and error I seem to have the f1703 back to work again: by setting the brightness to its very minimum before I switch the monitor off.
Looks like the monitor is reaching the end of its life, but I have spend so much time in trying to repair it, I’m not letting it go yet…
September 21st, 2010 at 5:24 PM
Todd, I thought the output voltage of the AC supply was around 12V. Running it at ~18V-19V might work for a while (your “fair amount of tolerance for input voltage”), but you must see why things start to fry after a while.
September 21st, 2010 at 4:29 PM
thanks for the reply with regard to that resistor Leslie.
I have another question.
I also have a f1503, I am assuming they run the same inverter board.
I inadvertently plugged the power adaptor from my N610C laptop (18v DC) the night the f1703 inverter board blew, this subsequently blew Q212 and Q211 I will replace these, will also replace Q210 & Q209 to be sure. R128 is fried and not showing any resistance, all fuses are ok?
Looking at the f1503 I am using, the power adaptor is rated at 19v @ 3.16A DC. I know it is the wrong adaptor, however it works!!
It would seem the f1503 board has a fair amount of tolerance for input voltage. Secondly, the f1703 only had 18v @ 3.61A, I recall it turned on and then a “That Smell” come from it (Inverter transistors).
Would it be a fair call to say the f1703 had an underlying issue when I run the 18v into it.
Any insight appreciated.
September 21st, 2010 at 4:20 AM
Hi – just wondering what the resistor at r128 is, looks like a 1 watt, but is is black (someone threw 18v at it)
4 Trannys are also gone, they are on the way.
Anything else to look out for?