Hi,
I have an NEC 1545v LCD which has worked fine for a month and a half, but recently it has a strange problem. It will run fine, but then start turning on and off for a while. If I turn it off and straighten all the connections it will start up fine, but this keeps happening after a random amount of time. Does anybody know what I could do to fix this? Is a fuse blown or something?
Thanks!
I have an NEC 1545v LCD which has worked fine for a month and a half, but recently it has a strange problem. It will run fine, but then start turning on and off for a while. If I turn it off and straighten all the connections it will start up fine, but this keeps happening after a random amount of time. Does anybody know what I could do to fix this? Is a fuse blown or something?
Thanks!
You really need to troubleshoot it to learn the cause. Take it one step at a time.
What do the status lights tell you? Power on/off? Signal on/off?
Did you note whether or not the monitor powers off completely or goes black due to the backlighting turning off? If so, go to the first step.
Does the monitor display a “no signal” message? If so, it is due to a signal loss, go on to the next step.
First Step; if the monitor uses a plug in power supply converter, rig up a method to check the output voltage while the monitor is running (you will probably have to access the power supply board in the monitor and make your connections there). Note the voltage when the monitor begins shutting off. If there is a significant drop in supply voltage, make a note of it. And check the converter box to see if it is abnormally hot. This could indicate a failing power supply, or an excessive current draw. If there is a significant voltage drop, you will then need to test the current draw. You will have to get creative here, but the easiest way would be to buy a female jack that matches the one on the monitor, and a male plug that matches the power supply plug. Wire them together with a short length of speaker wire, but cut the positive side wire in half at the middle and strip back the insulation about a half inch on each side of the cut.
Now you can plug this test jig in between the power supply and the monitor and hook the test leads of your VOM to the cut positive wires to get your current draw.
Make a note of what it is when the monitor cuts off. If the current draw significantly increases, you can rule out the power supply as the cause, and look further into the monitor.
Likely suspects are the power supply board in the monitor, and the high voltage power supply board for the backlights.
If all of this checks out good, go to the next step.
Next Step; check for continuity on all pins of the cables. Use a continuity tester (a decent VOM [volt ohm meter] with have one) or ohm meter to check for an unbroken signal path from each pin of the connector to the corresponding one on the other end.
If all of that checks out, go to the first step.
If you are still having trouble and cannot locate the source, you may have to ask yourself if you should refer to a qualified professional for repair. If you still want to slug it out, I will do what I can to help.
Dean Schumann
Audio Technician
Capitol Radio & TV
360-956-3666
2513 East Fourth Ave.
Olympia, WA 98506
What do the status lights tell you? Power on/off? Signal on/off?
Did you note whether or not the monitor powers off completely or goes black due to the backlighting turning off? If so, go to the first step.
Does the monitor display a “no signal” message? If so, it is due to a signal loss, go on to the next step.
First Step; if the monitor uses a plug in power supply converter, rig up a method to check the output voltage while the monitor is running (you will probably have to access the power supply board in the monitor and make your connections there). Note the voltage when the monitor begins shutting off. If there is a significant drop in supply voltage, make a note of it. And check the converter box to see if it is abnormally hot. This could indicate a failing power supply, or an excessive current draw. If there is a significant voltage drop, you will then need to test the current draw. You will have to get creative here, but the easiest way would be to buy a female jack that matches the one on the monitor, and a male plug that matches the power supply plug. Wire them together with a short length of speaker wire, but cut the positive side wire in half at the middle and strip back the insulation about a half inch on each side of the cut.
Now you can plug this test jig in between the power supply and the monitor and hook the test leads of your VOM to the cut positive wires to get your current draw.
Make a note of what it is when the monitor cuts off. If the current draw significantly increases, you can rule out the power supply as the cause, and look further into the monitor.
Likely suspects are the power supply board in the monitor, and the high voltage power supply board for the backlights.
If all of this checks out good, go to the next step.
Next Step; check for continuity on all pins of the cables. Use a continuity tester (a decent VOM [volt ohm meter] with have one) or ohm meter to check for an unbroken signal path from each pin of the connector to the corresponding one on the other end.
If all of that checks out, go to the first step.
If you are still having trouble and cannot locate the source, you may have to ask yourself if you should refer to a qualified professional for repair. If you still want to slug it out, I will do what I can to help.
Dean Schumann
Audio Technician
Capitol Radio & TV
360-956-3666
2513 East Fourth Ave.
Olympia, WA 98506
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