Jaycar MkII Teething

[allstarnz]

very insightful, thanks very much GW1.

In my first post there are two HQ pics of my board.

FYI, I am putting the probes incorrectly as below

[allstarnz]

Double-check you correctly understand IC pin numbering.

that be it. I was taking measurements across pins 7 and 8, as you can see from above.

Here is the correct info



the thing that threw me was that the other two IC's had correct readings so I thought nothing of it.

So i'm off to buy a cable tomorrow, if I can't find one lying around work.

[gw1]

Just to make it clear, so that people don't look at the photo above and get the wrong idea, here are the IC supply voltage measurement points:



You want red probe on pin 14 and black one on pin 7. The reason you were measuring 2.7V on IC2 (the RHS one above) is you were measuring pin 8, the clock signal. It's a square wave swinging between 0V and 5V, the average over time being halfway between the two.

[allstarnz]

good pointers for future reference GW1.

Got my cable today, so can have a play when I get home.

[jrmargi]

Read the post about the nail polish........i generally laquer the back of all my boards once they are working 100%...............

I feel for you man nothing worse than probs like this..........