MAG LT916s 900P Inverter Mirage Electronics AD-1700 Rev:F 200-000-170DTL1 VERSION:A
Sticker: 860-AB0190DTL1-A AD-190DTL1 J22-001 A 5083725
One by one these are dying. The symptom is that it powers off 2 seconds after turning on. The first I played with the inverter long enough and swapped enough parts to break it completely. Pictured is the second. In circuit ESR testing shows 0.03 ohms with the two Fuhjyyu 470uf 25v output parallel cap pairs and 0.05 ohms with the two single Fuhjyyu output caps. I've pulled and tested the xunda 100uf 400v input cap and its 0.75 ohm ESR looks good too. 100uf caps C10 & C11 are 0.00 ohms so are unmeasurable in circuit and the remaining caps test with good ESR.
The 3rd dead Mag LT916s has been delivered and is working but like the others the runtime will get shorter and shorter until it gets to 2 seconds where it can't be used any more. I haven't even opened it up.
Playing with the first inverter I found that the boards will shut down if you pull too much current, and those sparks and corona effects sure are nifty. One problem might be that aging lamps have increased their current draw and this board doesn't have enough headroom. Unfortunately it's not worth buying new lamps just to find out the old lamps are fine. Turning down the intensity may alleviate this problem for a while but that's hard when the runtime is 2 seconds.
I've also fixed a PC power supply by replacing all of it's bad brand good caps with good brand good caps. That might mean that there are things that go wrong with caps that push marginal circuits out of spec that our meters can't test. Unfortunately I have no 100uf 400v caps and not nearly enough 470uf 25v caps on hand to do 3 monitors only to find out that the Fuhjyyu caps aren't bad yet.
I wouldn't mind a replacement inverter board but since these Mirage units seem defective a replacement would need to be beefed up before I'd trust it. No one sells this inverter yet.
Replacement LCD screens similar to this HannStarr HSD190ME12-A00 LCD are getting dumpster prices so selling the screen isn't an option.
http://forum.electronicwerkstatt.de/...1_bz0_bs0.html
http://www.elektroda.pl/rtvforum/topic746362.html
http://www.google.com/search?hl=en&q...=Google+Search
http://www.google.com/search?hl=en&q...ay&btnG=Search
The input is regulated by an 8 pin chip IC201 203D6 PSDI and the HV inverter has a 16 pin chip IC1 TL494C and two large transistors U1 & U2 D444 (2SD444). The schematic at elektroda.pl looks nice but it doesn't match up with what I see.
BLON and BRI go directly into the inverter section. Perhaps I could defeat the cutoff circuit by cutting the BLON trace and hardwire it to something, assuming the BLON trace does something other than shut off the monitor during power save. The inverter probably has its own safety circuit independent of BLON.
Fortunately we have some sun so my pictures don't suck. The pulled solder pad near the 8 pin chip is to the 100uf cap. I haven't soldered it back in yet.
Sticker: 860-AB0190DTL1-A AD-190DTL1 J22-001 A 5083725
One by one these are dying. The symptom is that it powers off 2 seconds after turning on. The first I played with the inverter long enough and swapped enough parts to break it completely. Pictured is the second. In circuit ESR testing shows 0.03 ohms with the two Fuhjyyu 470uf 25v output parallel cap pairs and 0.05 ohms with the two single Fuhjyyu output caps. I've pulled and tested the xunda 100uf 400v input cap and its 0.75 ohm ESR looks good too. 100uf caps C10 & C11 are 0.00 ohms so are unmeasurable in circuit and the remaining caps test with good ESR.
The 3rd dead Mag LT916s has been delivered and is working but like the others the runtime will get shorter and shorter until it gets to 2 seconds where it can't be used any more. I haven't even opened it up.
Playing with the first inverter I found that the boards will shut down if you pull too much current, and those sparks and corona effects sure are nifty. One problem might be that aging lamps have increased their current draw and this board doesn't have enough headroom. Unfortunately it's not worth buying new lamps just to find out the old lamps are fine. Turning down the intensity may alleviate this problem for a while but that's hard when the runtime is 2 seconds.
I've also fixed a PC power supply by replacing all of it's bad brand good caps with good brand good caps. That might mean that there are things that go wrong with caps that push marginal circuits out of spec that our meters can't test. Unfortunately I have no 100uf 400v caps and not nearly enough 470uf 25v caps on hand to do 3 monitors only to find out that the Fuhjyyu caps aren't bad yet.
I wouldn't mind a replacement inverter board but since these Mirage units seem defective a replacement would need to be beefed up before I'd trust it. No one sells this inverter yet.
Replacement LCD screens similar to this HannStarr HSD190ME12-A00 LCD are getting dumpster prices so selling the screen isn't an option.
http://forum.electronicwerkstatt.de/...1_bz0_bs0.html
http://www.elektroda.pl/rtvforum/topic746362.html
http://www.google.com/search?hl=en&q...=Google+Search
http://www.google.com/search?hl=en&q...ay&btnG=Search
The input is regulated by an 8 pin chip IC201 203D6 PSDI and the HV inverter has a 16 pin chip IC1 TL494C and two large transistors U1 & U2 D444 (2SD444). The schematic at elektroda.pl looks nice but it doesn't match up with what I see.
BLON and BRI go directly into the inverter section. Perhaps I could defeat the cutoff circuit by cutting the BLON trace and hardwire it to something, assuming the BLON trace does something other than shut off the monitor during power save. The inverter probably has its own safety circuit independent of BLON.
Fortunately we have some sun so my pictures don't suck. The pulled solder pad near the 8 pin chip is to the 100uf cap. I haven't soldered it back in yet.
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