Hi everyone,
New guy here. Been lurking and reading for awhile now and all I can say after looking at some other forums out there is WOW! The people and information here is fantastic! The forums here have helped me fix a couple of things already (computer PSUs that I thought were ready for scrap heap.) Just a little FYI about me, I was a electronics tech. about 30 years ago, (back in the good old days of analog). Trouble shot and repaired TV sets, amplifiers, radios things like that. I got out of it about the time the digital revelution took over. I have still stuck with some of it as a hobbiest and have built things and fixed things here and there.
I can usually trip, stumble and muddle my way through fixing things but I am stuck and need some help. My son recently got an Acer AL1916W A monitor. When he got it the backlights would not come on. The display worked, you could see it with a flashlight. The power light lit up green but no backlights. We checked online at svereal forums and settled here do to the vast information. After reading the forums related to this monitor we opened it up. It has the DAC19m005 power board in it. We found several bad caps, the FETs were bad and the fuse F200 was blown. We got a rebuild kit for this power board that has Nichicon HE caps (with exception of 47uf 50v cap that was not in with the kit and a low esr one is on order now), 2 new FETs and a replacement fuse.
After replacing all the parts, except 47uf cap, we plugged it in. The power light flashed green and the back lights flashed for an instant then went off. We hooked it up to a pc in case it needed a signal to startup and got no joy.
If we unplgged the monitor and plugged it back in it would flash (backlights and power light but that was it. We opened up the monitor and I began checking voltages. Fuse F200 was not blown to my suprise. The 12v supply had 13.86 volts on it and the 5v supply had 5.02. With the power board diconected from the logic board these voltages held steady. We connected it back up to the logic board and plugged it in. The 12v supply jumped to 13.86 volts been then slowly dropped to 2.2 volts. The 5v supply came up to 5.02 volts and then slowly dropped to 0.1 volts. (To me it seems like the power supply shut down when connected to the logic board and the voltage drop I was seeing was the caps discharging).
While double, maybe tripple checking voltages while pluging and unpluging the monitor my meter probe slipped and I belive I shorted the 12v supply. When I did this the power light came on orange and 12v supply shot up to 15.1v and the 5v supply came up to 5.02 volts and held. No back lights came on. We again hooked to pc and still nothing.
We pulled the power board again and found that fuse F200 had blown and the 12v supply was at 15.01 volts. If a momentarily jumped f200 the voltage goes back down to 13.86.
Things I have checked so far, FETs appear to be good by meter, secondaries on CCFL transformer are 652 ohms and 655 ohms, primaries are suppossed to be .3 ohms but my meter wont read that low, but does show continuity. On U200 I have no voltages anywhere. Looking at the spec sheet for the 3713 chip it shows pin 10 being vdd. I beilive it may be looking for a signal from the logic board though to turn it on.
Anybody got any ideas or have a schenatic for this? I will get photos uploaded as soon as I figure out how to resize them.
New guy here. Been lurking and reading for awhile now and all I can say after looking at some other forums out there is WOW! The people and information here is fantastic! The forums here have helped me fix a couple of things already (computer PSUs that I thought were ready for scrap heap.) Just a little FYI about me, I was a electronics tech. about 30 years ago, (back in the good old days of analog). Trouble shot and repaired TV sets, amplifiers, radios things like that. I got out of it about the time the digital revelution took over. I have still stuck with some of it as a hobbiest and have built things and fixed things here and there.
I can usually trip, stumble and muddle my way through fixing things but I am stuck and need some help. My son recently got an Acer AL1916W A monitor. When he got it the backlights would not come on. The display worked, you could see it with a flashlight. The power light lit up green but no backlights. We checked online at svereal forums and settled here do to the vast information. After reading the forums related to this monitor we opened it up. It has the DAC19m005 power board in it. We found several bad caps, the FETs were bad and the fuse F200 was blown. We got a rebuild kit for this power board that has Nichicon HE caps (with exception of 47uf 50v cap that was not in with the kit and a low esr one is on order now), 2 new FETs and a replacement fuse.
After replacing all the parts, except 47uf cap, we plugged it in. The power light flashed green and the back lights flashed for an instant then went off. We hooked it up to a pc in case it needed a signal to startup and got no joy.
If we unplgged the monitor and plugged it back in it would flash (backlights and power light but that was it. We opened up the monitor and I began checking voltages. Fuse F200 was not blown to my suprise. The 12v supply had 13.86 volts on it and the 5v supply had 5.02. With the power board diconected from the logic board these voltages held steady. We connected it back up to the logic board and plugged it in. The 12v supply jumped to 13.86 volts been then slowly dropped to 2.2 volts. The 5v supply came up to 5.02 volts and then slowly dropped to 0.1 volts. (To me it seems like the power supply shut down when connected to the logic board and the voltage drop I was seeing was the caps discharging).
While double, maybe tripple checking voltages while pluging and unpluging the monitor my meter probe slipped and I belive I shorted the 12v supply. When I did this the power light came on orange and 12v supply shot up to 15.1v and the 5v supply came up to 5.02 volts and held. No back lights came on. We again hooked to pc and still nothing.
We pulled the power board again and found that fuse F200 had blown and the 12v supply was at 15.01 volts. If a momentarily jumped f200 the voltage goes back down to 13.86.
Things I have checked so far, FETs appear to be good by meter, secondaries on CCFL transformer are 652 ohms and 655 ohms, primaries are suppossed to be .3 ohms but my meter wont read that low, but does show continuity. On U200 I have no voltages anywhere. Looking at the spec sheet for the 3713 chip it shows pin 10 being vdd. I beilive it may be looking for a signal from the logic board though to turn it on.
Anybody got any ideas or have a schenatic for this? I will get photos uploaded as soon as I figure out how to resize them.
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