
Connect the negative lead of the ohmmeter to pin 4 of J10 (-V). This should also read at
minimum of a few hundred ohms. If it doesn’t read 0 Ohms, then your power supply
rails are not shorted together. If you get a reading of 0 or 1 or 2 Ohms in any of these
checks – STOP! Fix the problem; then move on.
Now, check to see that +V and ground will make it to the Digital Board. Connect the
positive lead of the ohmmeter to pin 1 of J10 and connect the negative lead to pin 1 of
J11. There should be zero Ohms or really, really close to it. If so, your positive rail will
make it to the Digital Board, taking for granted your cable is well constructed. There’s
always something to worry about.
Connect the positive lead of the Ohmmeter to pin 3 of J10 and the negative lead to pin 2
of J11. If it reads zero ohms or something tantamount to zero ohms, your Digital Ground
signal should make the trip between boards.
For those who have installed W1 on the Analog Board, connect the positive lead to pin 2
of J10 and the negative lead to Pin 2 of J11. If you get zero ohms or something
ludicrously close to it, your W1 jumper is well soldered and good to go analog ground
and digital ground are connected together at this point.
Check the IC Positive Power Pins
Next up, it’s another drill you just performed with the Digital Board. It’s time to check
the positive supply pins of all the ICs. Connect the positive ohmmeter lead to pin 1 of
J10 and check the pins in Table 8-3.
Ref Des
Device
Positive Supply Pin
U1 CD4066
Pin
14
U2 CD4066
Pin
14
U3 CD4066
Pin
14
U4 CD4066
Pin
14
U5 78L10 Pin
1
U6 TL072 Pin
8
U7 CD4051
Pin
16
U8 TL074 Pin
4
U9 TL074 Pin
4
U10 TL074 Pin
4
Table 8-3: Analogue Board IC Positive Supply Pins
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