Hi all,
I got hold of a defective Samsung 2493 monitor. The previous owner told me it stopped working after he heared a loud pop. He said it smelled like something had burned. Visible phenomenon when switching the monitor on: screen just stays black, no image visible with a flashlight, power led stays blue. He told me Samsung advised him the warranty had already expired, and repair just would not be cost-effective. So he had just put the 2493 aside and gotten himself a new 27" led monitor.
After opening the case it was immediately clear the careful owner hadn't told the whole truth. Judging by the solder joints all secondary caps and the TO-220 diodes and fets on the PSU (BN44-00195A) had already been replaced or resoldered. No visible damage to any components. I resoldered all through-hole components just to be sure no cold solder joints were left. Sadly without any improvement, still a black screen with solid power led.
Thankfully I have a 245B with exactly the same PSU. Swapping boards revealed that not only the PSU is defective, but the T-con as well. Who knows what other defects the previous owner didn't bother to tell me.
Thankfully the screen itself is intact, no vertical discolored lines or cracks.
Careful inspection revealed that either he or a so-called repairman had gone through the trouble of sloppily replacing ICM851 (Sanken SL8008hfe). This IC is mounted on a colling fin behind a large coil. Apparently the 'repairman' couldn't fit it with its back flat on the cooling fin, and had just vised in the retaining screw at an angle. In doing so the IC was fitted at an angle as well, so may well have overheated. Possibly the reason why the PSU had failed again.
I decided to start with fixing the PSU. Recapped it for good measure, replaced the 12n 630V MKP cap, removed all brown glue, checked both fuses and the current limiting resistors on fets QM802 and QM803 (are all OK). I left the SL8008 in for the time being, no need to indisciminately swap parts yet. Again no result, monitor still gives just a black screen with solid blue power led.
So, now there's no way around doing some measurements with my multimeter on a live PSU. Thankfully the schematic for BN44-00192A, posted in one of the other 2493 threads, is largely similar.
After fixing the PSU the T-con will need my attention. At first I suspected the fuse was shot, but it turns out to be OK. Strange. I hope the fault is not with the ceramic caps this board is littered with. It may be a shot LM1117 3,3V regulator, there are 2 of these on the T-con.
I'll post my findings here, I hope someone chimes in with suggestions and directions.
I would really like to get this monitor working again, it will make a nice father's day present for my parents. That leaves me several weeks of time to tinker with it.
re-atari
I got hold of a defective Samsung 2493 monitor. The previous owner told me it stopped working after he heared a loud pop. He said it smelled like something had burned. Visible phenomenon when switching the monitor on: screen just stays black, no image visible with a flashlight, power led stays blue. He told me Samsung advised him the warranty had already expired, and repair just would not be cost-effective. So he had just put the 2493 aside and gotten himself a new 27" led monitor.
After opening the case it was immediately clear the careful owner hadn't told the whole truth. Judging by the solder joints all secondary caps and the TO-220 diodes and fets on the PSU (BN44-00195A) had already been replaced or resoldered. No visible damage to any components. I resoldered all through-hole components just to be sure no cold solder joints were left. Sadly without any improvement, still a black screen with solid power led.
Thankfully I have a 245B with exactly the same PSU. Swapping boards revealed that not only the PSU is defective, but the T-con as well. Who knows what other defects the previous owner didn't bother to tell me.
Thankfully the screen itself is intact, no vertical discolored lines or cracks.
Careful inspection revealed that either he or a so-called repairman had gone through the trouble of sloppily replacing ICM851 (Sanken SL8008hfe). This IC is mounted on a colling fin behind a large coil. Apparently the 'repairman' couldn't fit it with its back flat on the cooling fin, and had just vised in the retaining screw at an angle. In doing so the IC was fitted at an angle as well, so may well have overheated. Possibly the reason why the PSU had failed again.
I decided to start with fixing the PSU. Recapped it for good measure, replaced the 12n 630V MKP cap, removed all brown glue, checked both fuses and the current limiting resistors on fets QM802 and QM803 (are all OK). I left the SL8008 in for the time being, no need to indisciminately swap parts yet. Again no result, monitor still gives just a black screen with solid blue power led.
So, now there's no way around doing some measurements with my multimeter on a live PSU. Thankfully the schematic for BN44-00192A, posted in one of the other 2493 threads, is largely similar.
After fixing the PSU the T-con will need my attention. At first I suspected the fuse was shot, but it turns out to be OK. Strange. I hope the fault is not with the ceramic caps this board is littered with. It may be a shot LM1117 3,3V regulator, there are 2 of these on the T-con.
I'll post my findings here, I hope someone chimes in with suggestions and directions.
I would really like to get this monitor working again, it will make a nice father's day present for my parents. That leaves me several weeks of time to tinker with it.
re-atari
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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