Pull down resistors that don't

[Born in Brum]

I am trying to build a 'virtual' version of a PICAXE test board that I use in my school with students from Y9 to Y13 (ages 13 to 18).
The outputs work fine with a variety of bits (LEDs, piezo buzzers, LCD screens etc) but the problem is with switches connected to the inputs.
I have built it exactly like the real boards (and I know they work, we have made nearly 100 now) and actually in the same way as the sample file for the AXE050 tutorial board (but as it is a sample file I can't access the properties of components to see what they have done).
The problem seems to be that the 10k pull down resistors are not pulling the voltage at the inputs low when the switch is not pressed - the voltage reamins 'high' whether the switch is pressed or not. I have made the 10k resistors 'digital' models but this has no obvious effect in this case.
I am fairly certain that this fits into the "You forgot to do this..." category but would welcome anyone offering any advice on the matter
Many thanks

PS and slightly OT if anyone knows of a real idiots guide to setting GMIN etc when you get errors (rather than flailing around in the dark guessing values) I would be very grateful

 

[Technical]

You don't have the default 'digital' 5V supply on your circuit, as you have derived 5V from an analogue model instead ( 9V / 7805) ). This is ok to do, but the digital simulation engine (for the digital resistors) does not then have a default 5V reference to work from.

So, either:
1) Change the resistors to analogue models
or
2) just drop a 5V power terminal anywhere on screen (right click>place>terminal>power). It doesn't need to be connected to anything, it just needs to be there!

Either works for us with this test program:

main:
if pin0= 1 then dohigh
low 4
goto main
dohigh:
high 4
goto main

 

[Born in Brum]

Many thanks for a very rapid and helpful reply - your suggestion works a treat.