Greetings,
I have a HP H1955 monitor. The monitor is obviously old (from 2005) and a similar replacement monitor wouldn’t be particularly expensive and hard to get hold on. The problem is that I'm using it for a custom built special purpose so it would be tedious and might take a while to find an exact replacement.
Description of problem
Suddenly it went black during use. When I restarted it, it stayed on for 1-2 seconds then went black again. This was repeated a couple of times. Then a burned smell came from the monitor and from that point the backlight was not coming on at all anymore. However the video processing is obviously still working. If I light on it with a flashlight I can clearly see the image. Thus I conclude that it’s a problem with the backlight.
Troubleshooting so far
I found lots of information regarding problems with this type of monitor in this thread:
https://www.badcaps.net/forum/showthread.php?t=8598
However, my board doesn’t seem to be identical so I’m not entierly sure what to check more than I have already done.
I have found the following problems so far:
Questions
Sorry I'm not used to working on PCB:s but I’m a quick learner and have basic knowledge and soldering tools. Any help in getting this sorted would be greatly appreciated.
Thanks so much and cheers from Sweden.
I have a HP H1955 monitor. The monitor is obviously old (from 2005) and a similar replacement monitor wouldn’t be particularly expensive and hard to get hold on. The problem is that I'm using it for a custom built special purpose so it would be tedious and might take a while to find an exact replacement.
Description of problem
Suddenly it went black during use. When I restarted it, it stayed on for 1-2 seconds then went black again. This was repeated a couple of times. Then a burned smell came from the monitor and from that point the backlight was not coming on at all anymore. However the video processing is obviously still working. If I light on it with a flashlight I can clearly see the image. Thus I conclude that it’s a problem with the backlight.
Troubleshooting so far
I found lots of information regarding problems with this type of monitor in this thread:
https://www.badcaps.net/forum/showthread.php?t=8598
However, my board doesn’t seem to be identical so I’m not entierly sure what to check more than I have already done.
I have found the following problems so far:
- What appears to be a faulty solder on one of the gray caps (see attached image).
- Shorted transistors: When I measure the resistance, the two C5707s transistors on the sides of the gray cap with faulty solder show no resistance, however I measure them. The two others seem fine. (See attached images.)
- If I measure resistance over the fuse (see attached image marked "PF701" on the board) I get 139 Ohms when tested in circuit. I guess that may indicate that it’s been burned. Or do I need to desolder it to test it? (according to the link above, no backlight at all may indicate a burned fuse).
Questions
- Before ordering parts, what additional troubleshooting can I do and how can this be done?
- According to this post https://www.badcaps.net/forum/showpost.php?p=144403&postcount=15 the “fu9024” should be checked for shorts. However. I’m not sure which part this would be and how it should be tested.
- Is it worth a shot to fix this? Or is it likely that any irreparable damage has occured?
- If I find another HP monitor of similar age, say with other dimensions, are the power supply boards swappable?
Sorry I'm not used to working on PCB:s but I’m a quick learner and have basic knowledge and soldering tools. Any help in getting this sorted would be greatly appreciated.
Thanks so much and cheers from Sweden.
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