Chosen Solution
Hey folks, I have this neat older monitor that I’d like to preserve. It still has a very functional resolution and size (2560 x 1600 @ 30"). These are notorious for having overheating scaling chips on the T-con, yet I don’t think that is my problem as the screen is simply black (or it occasionally works) and T-con failures are colorful, right? At least, there are telltale artifacts and such before they fail completely, correct? I never had any hint of it going bad. Just lots of instances where I would have to shut it off, fiddle with the DVI, and plug it back in to get a signal. I’m honestly not sure the plugging had any effect more than the power cycling. Although, if there is a bad connection in a solder somewhere, the plugging may have moved it slightly enough to make contact. Taking it apart, I found some obviously bad caps on the PS board, so I recapped all the capxons except the large main cap and two Rubycons. This changed nothing. I since pulled the two Rubycons and the large main to test. The Rubycons (35V1000uf) test at Vloss 0.5~0.8, C is at ~930uf, and ESR is 0.00-0.01ohms. The main (450V150uf) tests at Vloss 1, C is ~135uf, and ESR is 0.46ohms. Should I replace these? I’m starting to think the problem lies in the main, or the ribbon connectors. Any ideas? See pics here
Hi, When the screen is black, shine a torch at an angle close to the screen and check for images. They will be very faint if they are there, so trying this in a darkened room may help to see them. If there are images to be seen on the screen, there’s a backlight problem Here’s the block diagram from the service manual which may help although it’s not a schematic. Check if there is +24V on CN 402 (I don’t know which pin so you may have to check all of them). If not then the problem is in the inverter section of the power board. If there is check for voltage on the BL_EN(backlight enable) lead on CN 402. Again I don’t know which pin and but maybe look for a voltage between 3V-5V as this is mostly the case with display backlight enable. Usually there is always voltage supplied to the backlights but it is turned on and off in the screen by a signal voltage sent/removed on the BL_EN lead. The way to find the lead maybe is to check the voltages on CN402 (all pins - write them down) when there is a display for the 10% of the time and then check again when there is no display. If there are no images then it’s looking like a mainboard problem, especially if there is +24V for the backlights.
could be a connection issue, try unplug and replug all the connectors a few times, then test it.
