Measuring Voltages in a LCD monitor

[Solder Boy]

Hi guys tried doing a search of this topic before making this post, not sure if the question has been asked before.

I'm aware checking for proper voltage can be crucial when repairing LCD's just not totally clear on the proper way to do it.

If you have the LCD disassembled.. where do you measure for the 12volt rail etc? What is the procedure? Example: when checking voltages to the logic board.. do you keep the connector between the power/inverter board on or do you do remove it?

I read about putting the negative lead to a ground screw on the chassis, that much I understand.. just not sure where to insert the red lead.. do you insert it in the cable from the power board that goes to the logic board?

Thanks again guys!

[retiredcaps]

Re: Measuring Voltages in a LCD monitor

I'm aware checking for proper voltage can be crucial when repairing LCD's just not totally clear on the proper way to do it.

I don't know if my way is "proper" especially for a person that has only been using a multimeter for 6 months, but I'll describe what I do.

If you have the LCD disassembled.. where do you measure for the 12volt rail etc? What is the procedure? Example: when checking voltages to the logic board.. do you keep the connector between the power/inverter board on or do you do remove it?

I look for the 12V (or secondary voltages) on the connector between the power board and logic board. I find it easiest to measure at the connector. I keep the boards connected.

You can also find 12V DC on the dual diodes.

I read about putting the negative lead to a ground screw on the chassis, that much I understand.. just not sure where to insert the red lead.. do you insert it in the cable from the power board that goes to the logic board?

For GND, I usually put my black probe on the ground screw that is closest to the connector.

For the red probe, it depends. If the backside is facing me, it is pretty easy to just put the red probe on the various solder points off the connector.

If the frontside is facing me, I'll usually use the connectors themselves.

Hopefully that makes sense. If not, please ask clarification questions.

[retiredcaps]

Re: Measuring Voltages in a LCD monitor

PS. For mains voltage measurement, I *was* using 2 hands (one for red probe and one for black probe) to measure the main filter capacitor, but I recently got some aligator clips/leads and will using these in the future.

So I will clip on the aligator leads to the main filter capacitor and then hook up to my multimeter. Put it on V DC, double check my connections and only then, hit the power bar on button.

With this new method, I'm less likely to get shocked if something goes really bad.

[shovenose]

Re: Measuring Voltages in a LCD monitor

Lol unless your dmm blows up!