Hey All,
I am having issues with my monitor. Anytime it goes into standby mode for more than a minute or so, it won't wake up. The power LED either turns back blue or it goes into an on and off cycle. Either way the screen stays black or occasionally goes completely white and the front panel is unresponsive. I have to unplug the monitor from the power socket and leave it unplugged for at least 5 minutes and then plug it back in for it to start working again.
I opened the monitor to check for any bulging or leaking caps but I haven't found anything visibly wrong on either the power supply or the main board. I decided to ordered a replacement power supply which seemed to work fine for about a month until the same problem returned. Next thing I tried was to replace some of the capacitors on the power supply. I circled which, in one of the pictures. That sort of helped for maybe a week.
I was thinking of maybe going ahead and replacing the main filter capacitor but before I got around to it the left side of the monitor went dim. I did replace the main filter cap after that with the one from the old power supply but it made no difference.
Searching the forum I found this old thread of someone with the same monitor where one of the users suggested to measure the dc voltage between some of the points, so I went ahead and did that and post what I managed to measure in the last picture (the yellow circle is ground).
Lastly I found a service manual pdf to a different monitor that uses a variant of the same power supply. It has some schematics of it around the page 83 and 93. However the model JC240XX that's in the pdf has some differences to the JT240XX that my monitor uses like the extra caps in the top right corner. So I don't how much of a help it will be to anyone, either way it's in the attachments.
Thanks for reading and any help would be appreciated.
I am having issues with my monitor. Anytime it goes into standby mode for more than a minute or so, it won't wake up. The power LED either turns back blue or it goes into an on and off cycle. Either way the screen stays black or occasionally goes completely white and the front panel is unresponsive. I have to unplug the monitor from the power socket and leave it unplugged for at least 5 minutes and then plug it back in for it to start working again.
I opened the monitor to check for any bulging or leaking caps but I haven't found anything visibly wrong on either the power supply or the main board. I decided to ordered a replacement power supply which seemed to work fine for about a month until the same problem returned. Next thing I tried was to replace some of the capacitors on the power supply. I circled which, in one of the pictures. That sort of helped for maybe a week.
I was thinking of maybe going ahead and replacing the main filter capacitor but before I got around to it the left side of the monitor went dim. I did replace the main filter cap after that with the one from the old power supply but it made no difference.
Searching the forum I found this old thread of someone with the same monitor where one of the users suggested to measure the dc voltage between some of the points, so I went ahead and did that and post what I managed to measure in the last picture (the yellow circle is ground).
Lastly I found a service manual pdf to a different monitor that uses a variant of the same power supply. It has some schematics of it around the page 83 and 93. However the model JC240XX that's in the pdf has some differences to the JT240XX that my monitor uses like the extra caps in the top right corner. So I don't how much of a help it will be to anyone, either way it's in the attachments.
Thanks for reading and any help would be appreciated.
Attached Files
But today, I’m making an exception here. Why? No idea. Perhaps only because the repair details are still “fresh” in my head… which is ironic, given this is a 16 year old monitor that hardly anyone will care about today. It is new to me, though. 
I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
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