Quote Originally Posted by HenrikOlsson View Post

Fit a 1k-2k resistor then verify the operation in steps.
1) Measure the voltage at the PIC output, it should be either 0 or 5V (or close to it). If it's not then something is wrong.
2) Measure the voltage at the base of transistor, it should be either 0 or 0.6V (or close to it). If it's not something is wrong.
3) Measure the voltage at the collector of the transistor, it should be 5V when the transitor is OFF and close to 0 when the transitor is ON.

If it doesn't work please do the above measurments and report the results.

/Henrik.
Fitted a 1.5K resistor

1) - Voltage out when the pin goes high = 4.52v
2) - Base of transistor voltage measured 0.73v
3) - Voltage at collector when PIC pin was HIGH was 0.03v and 5.01v when PIC pin was LOW

Still the relay contacts didn't switch.

Thinking it might be the regulator as I'm using a 200mA version of the 7805 I changed this for a traditional 1 amp version - still no change.

As the new relays are DIL footprint (16 pin DIL) and I am using sockets, I removed the relays and inserted the pins of the original relay into the contacts on the DIL socket. This relay also has a coil of 68 ohms so would be drawing similar current of around 80mA ? - The contacts changed over just fine. Last test was to attach two wires to the coil and plug this into the DIL socket - still no change, but plugging the coil directly across the 5v switched it hard...

I'm going to re-breadboard the hardware with the DIL relays and see if it switches OK just to rule out a fault on the stripboard (my eyes are not what they used to be - so I could have a dry joint or short somewhere !) - but I don't hold up much hope as any such issues should of resulted in the same thing happening with the original relay when tested with the stripboard.....