How to measure pcb test point on assembled module

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DanaFo
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How to measure pcb test point on assembled module

Post by DanaFo » Tue Jan 12, 2021 11:37 am

So, I'm about to finally power up my assembled module... in the instructions there's a test point for calibration on the pcb itself - but there's no definite info on google on how to actually use a multimeter with this. Do I put the red probe on the test point and the black probe... on the case rail? There's no obvious ground point I can see...?


Thanks!

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htor
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Re: How to measure pcb test point on assembled module

Post by htor » Tue Jan 12, 2021 12:07 pm

put the red probe on the test point and the black one to 0V (ground). you'll find ground points in several places in the circuit. for instance a resistor leg going to ground is optimal and easily accessible. or an IC power pin for instance. just pick one. if this is hard to find, you always have the power connector for the PCB which has ground pins.

DanaFo
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Re: How to measure pcb test point on assembled module

Post by DanaFo » Tue Jan 12, 2021 12:12 pm

htor wrote:
Tue Jan 12, 2021 12:07 pm
put the red probe on the test point and the black one to 0V (ground). you'll find ground points in several places in the circuit. for instance a resistor leg going to ground is optimal and easily accessible. or an IC power pin for instance. just pick one. if this is hard to find, you always have the power connector for the PCB which has ground pins.
very helpful, thank you!

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the bad producer
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Re: How to measure pcb test point on assembled module

Post by the bad producer » Tue Jan 12, 2021 2:59 pm

One thing I like to do on through hole test point pads is to get a resistor lead and bend it in half to make a little loop and solder the ends into the test point pad, this means you can easily attach a crocodile clip to the point and don’t have to worry about holding five things at the same time whilst looking at something else, I find pointy probes have a tendency of slipping and possibly causing a short somewhere!

DanaFo
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Re: How to measure pcb test point on assembled module

Post by DanaFo » Tue Jan 12, 2021 5:43 pm

the bad producer wrote:
Tue Jan 12, 2021 2:59 pm
One thing I like to do on through hole test point pads is to get a resistor lead and bend it in half to make a little loop and solder the ends into the test point pad, this means you can easily attach a crocodile clip to the point and don’t have to worry about holding five things at the same time whilst looking at something else, I find pointy probes have a tendency of slipping and possibly causing a short somewhere!
lol read my mind as I was trying it, thanks for the tip

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KSS
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Re: How to measure pcb test point on assembled module

Post by KSS » Thu Jan 14, 2021 7:10 am

Alternative for boards with TH test points is to solder in a square pin from a .100" 2,54mm male header and use one of the F-F patchcords for testing attachment. Like the M-M used on whiteboard breadboards and used with moog Werkstatt, Tangible waves modular, and Tinysizer. But female instead of male. <--available pretty much everywhere.

DanaFo
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Re: How to measure pcb test point on assembled module

Post by DanaFo » Thu Jan 14, 2021 7:11 pm

What I ended up doing was using a ground pin from the flying bus cable as the ground. But it looked like I could get similar readings from the ground pin from some of the ic's on the board.

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