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Tips on troubleshooting board PCB

Posted: Sun Sep 29, 2013 10:08 pm
by Mitb
First of all I am working with the original PCB design.

So I successfully completed the three blank board PCBs without issue and then turned my attention to the partially completed board. When it came time to do my initial power test while assembling I got 0.11 mA on the series test. This hasn't happened before on any of the other boards, and I can't see any bridges, whiskers, mustaches, etc that could be causing a short. I tested the continuity as best I could, but I thought I would ask and see if that reading is an indicator of anything for you. Also what would be my best course of action at this point?

Re: Tips on troubleshooting board PCB

Posted: Mon Sep 30, 2013 12:42 am
by Tony
If the 2R2 resistor is OK it might be a bad connection on the coil wires. What are the voltage readings round the microcontroller diodes?.

Re: Tips on troubleshooting board PCB

Posted: Mon Sep 30, 2013 1:03 am
by Mitb
The resistor is good and two of the diodes measure 46mV and one is around 60mV. The last one seems to steadily increase while I am reading it where as the first two sit steady.

Re: Tips on troubleshooting board PCB

Posted: Mon Sep 30, 2013 1:27 pm
by Tony
What is the voltage at each end of the 1k5 resistor?.

Re: Tips on troubleshooting board PCB

Posted: Tue Oct 01, 2013 4:27 am
by Mitb
It is showing 0mV.

Re: Tips on troubleshooting board PCB

Posted: Tue Oct 01, 2013 4:30 pm
by Tony
Are you sure the 2R2 is OK, do you have 12v at both ends?.

Re: Tips on troubleshooting board PCB

Posted: Sun Oct 06, 2013 8:19 am
by Mitb
Sorry about the deal getting back to you. I had to get a new fuse for my multimeter. I did recheck the 2R2 resistor and you are right, it is showing 0 volts.

Re: Tips on troubleshooting board PCB

Posted: Thu Oct 10, 2013 2:17 am
by Tony
Did replacing it help?.

Re: Tips on troubleshooting board PCB

Posted: Thu Oct 10, 2013 8:41 am
by Mitb
Yes replacing it helped but now when I run it through series to check the amps, I get .7amps and I begin to smell something burning :-(

On my next day off I am going to recheck the backside for any bridges. Any other advice for me?

Re: Tips on troubleshooting board PCB

Posted: Thu Oct 10, 2013 4:23 pm
by Tony
If it still has only one coil on, disconnect it. If it has more added now, quickly check the voltage drop across each of the 6r8 resistors, that should show which pair of transistors are in trouble.