Multimeter mishap caused dmres35v to die, next step? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 2 Old 07-03-2017, 10:04 AM - Thread Starter
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Question Multimeter mishap caused dmres35v to die, next step?

My aunt upgraded her old machine and was throwing it away so i asked if I coumd have it. She said that the remote no longer worked with the unit and I determined that she was correct, the ir sensor wasnt responding in the unit.

Usually I research how to properly do a job but this time I didnt. I want to learn from my mistake and more importantly learn how to further diagnose the device to find out what was damaged by my actions.

I broke out my old multimeter and had no idea what I was doing, I set it to tbe settings pictured here (pic of the sensor + pcb) imgur.com/a/q6chb

With the device fully powered on I then probed the pins on the sensor. I probed 3 different combinations of the pins, the first probes gave readings but the two pins I probed last caused the unit to power down and no longer powered back up again.

I completely disassembled the unit to check all of the components and have not spotted any blown caps, heat marks etc. I also checked the fuse and it is good.

I now know that what I did was foolish and served no real purpose, I have learned how to properly use the multimeter now as well as safety precautions.

How can I go about trying to find what damage I caused? I assume since the ir sensor was isolated on its own pcb (which is plugged into what I believe is the power board) that I may be able to narrow down where the damage was caused?

Or am I wrong about this and it is likely not possible to fix/find the damage that was caused?

I am hoping that I may be able to learn valuable things from this which will help me track down problems in broken devices I encounter in the future.

Thank you for your time, may post more pics if deemed helpful.
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post #2 of 2 Old 07-05-2017, 11:19 PM
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This is a bit outside my area of expertise, BUT, you had the multimeter set to Ohms, 20 Meg Ohms! This means it is inserting voltage into whatever you are testing. In this case, you are likely asserting nine volts into a delicate digital circuit that is not designed for anything near that level. This could have cascaded through the logic circuits of your machine doing all kinds of damage. Again, not my area of expertise. It could be minor, but it could be toast as well.

Luke

Evil is charming and beautiful. It makes you doubt yourself. It asks for one small compromise after another until it whittles you down, and it functions best when no one believes in it.-JOA
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