[Diy_efi] DIY-WB electrical problems

[rr]

Brian,

Having a working board will help immensely. Place the two
boards side by side and cross-check the components. Can
even use a DVM to check the resistance of one resistor then
the same resistor on the other board.

Then flip boards over to solder side and visually compare
the two. Look for solder shorts and differences between 
the boards.

On #12 below, 7.886V is close enough to 7.9 volts. Have to
keep in mind that even DVMs can be +-1%, with +- one digit
on top of that.

BobR.

Brian Renegar wrote:
> 
> I built two diy-wb units.  The first one worked perfectly.  But the second
> one is not working and seems to have some issues.  I followed the
> troubleshooting directions up through # 24, and it failed several of the
> tests.  Here's my results.
> 
> <DVM ground to J12>
> #10  Voltage at U4 pin 8 (should be 2.5V);  I got 4.433 V
> 
> #12  Voltage at U3 pin 5 (should be 7.9-8.0V);  I got 7.886V but sometimes
> it would decrease below that
> 
> <DVM ground to J7>
> #14  Voltage at U4 pin 14 (should be 0.45V);  I got -1.485V    Voltage at
> D8 pin 2 was correct though (1.231V)
> 
> #16  Voltage at U3 pin 12 (should be -4V);  I got 0.79 mV
> 
> #20  Voltage at U2 pin 5 and 9 (should be 0.45V);  I got 0.449V at pin 5,
> but -3.968V at pin 9
> 
> #22 Voltage at U3 pin 9 (should be 0V); I got 2.763V
> 
> I also got 0.4V at ISO1 pin1 and 2, but then checked again and got 0.1mV.
> 
> Any help figuring this out would be appreciated.
> Thanks,
> Brian
>

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