I'm working on a Dell 2405FPW for a co-worker and I'm having trouble figuring out what's wrong with it.
He told me that his wife saw the backlight flicker a couple of times, then the monitor wouldn't turn on anymore. I checked and found fuse F702 on the power supply board open; it's on the ~7v output. As a quick test, I ran the monitor with a multimeter in place of the fuse to see what the current draw was and everything worked fine (it drew about 1.5A). Since everything looked good there, I replaced F702 with a 5A pico-fuse (matched rating of the old one) and turned the monitor back on. I saw the same thing the owner reported, and some smoke from the general area of D652 (near the primary filter cap); this time F702 did not blow, but the monitor won't turn back on anymore.
I figured I'd also recap the power supply when I ordered the fuse, so I replaced the secondary filter caps (Elite) with Panasonic FM and the primary filter cap (also Elite) with this Panasonic ED as other info I've read about this monitor suggests that people have problems with it. After replacing the fuse, I replaced D652 (Fuji Electric YG971S6) with this close-looking one even though I think it's still working properly (didn't want to chance it with the smoke and all, didn't help though).
At this point, I measure about 19v on both sides of F701 and about 7v on both sides of F702 so I think the power supply is working properly. The monitor still won't turn on, so I'm thinking there's a problem in the display board. On the bottom of that board I found F9 (surface-mount, clear, labeled TP, near the input connector from the power supply) open and FD7 shorted. I'm having trouble figuring out what these things are. I'm assuming that F9 is a fuse of some sort, but it's not a type that I'm used to seeing and it doesn't have any indication of what rating it's supposed to have. Based on the logo, I think that FD7 is a diode of some kind manufactured by General Semiconductor (now owned by Vishay?), but the markings S4 57A haven't helped me figure out exactly what it is.
At this point I'm out of things to check (without checking every surface-mount component, of which there are a lot) and I'm having trouble finding information. Other people seem to have issues with the power supply on these monitors, but I think this one is okay. Elektrotanya doesn't have a service manual, I don't see parts on eBay, and I don't understand this stuff well enough to know where to go from here. Would anyone be willing to help me out?
He told me that his wife saw the backlight flicker a couple of times, then the monitor wouldn't turn on anymore. I checked and found fuse F702 on the power supply board open; it's on the ~7v output. As a quick test, I ran the monitor with a multimeter in place of the fuse to see what the current draw was and everything worked fine (it drew about 1.5A). Since everything looked good there, I replaced F702 with a 5A pico-fuse (matched rating of the old one) and turned the monitor back on. I saw the same thing the owner reported, and some smoke from the general area of D652 (near the primary filter cap); this time F702 did not blow, but the monitor won't turn back on anymore.
I figured I'd also recap the power supply when I ordered the fuse, so I replaced the secondary filter caps (Elite) with Panasonic FM and the primary filter cap (also Elite) with this Panasonic ED as other info I've read about this monitor suggests that people have problems with it. After replacing the fuse, I replaced D652 (Fuji Electric YG971S6) with this close-looking one even though I think it's still working properly (didn't want to chance it with the smoke and all, didn't help though).
At this point, I measure about 19v on both sides of F701 and about 7v on both sides of F702 so I think the power supply is working properly. The monitor still won't turn on, so I'm thinking there's a problem in the display board. On the bottom of that board I found F9 (surface-mount, clear, labeled TP, near the input connector from the power supply) open and FD7 shorted. I'm having trouble figuring out what these things are. I'm assuming that F9 is a fuse of some sort, but it's not a type that I'm used to seeing and it doesn't have any indication of what rating it's supposed to have. Based on the logo, I think that FD7 is a diode of some kind manufactured by General Semiconductor (now owned by Vishay?), but the markings S4 57A haven't helped me figure out exactly what it is.
At this point I'm out of things to check (without checking every surface-mount component, of which there are a lot) and I'm having trouble finding information. Other people seem to have issues with the power supply on these monitors, but I think this one is okay. Elektrotanya doesn't have a service manual, I don't see parts on eBay, and I don't understand this stuff well enough to know where to go from here. Would anyone be willing to help me out?
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