The picture to the right shows all the power wiring done. It was at this point that I applied a PSU and found my dead short caused by the uncut track... After rectifying this error, the power pins to each of the IC�s were checked to avoid any fried devices once  power is finally re-applied with the wiring completed and the IC�s in place.

And another two hours later we have the picture below with the wiring complete....

To the left you can see a picture of the project with it�s power wiring done along with the decoupling capacitors and pull-up resistors. Mmm. Please ignore the THIRD resistor down in the group at the top left. Er.. it shouldn�t have been there. Pins 26 and 27 on the 2764 EPROM need to go straight to +5V NOT via a pull-up resistor. The result? The oscilloscope revealed a permanently high data bus (like an blank EPROM would give)

Some may notice though that there is something that is not meant to be there- in the form of the blue �blob� under IC6. This is in fact not on the basic project drawings, and is part of the SYSTEM CLOCK which goes to Pin 6 of the Z80 CPU.

As I�ve explained in other places on this site, the CLOCK applied to the CPU can vary in frequency; and on this occasion I happened to have a 1MHz ceramic resonator to hand (something that�s very similar to a crystal) so I used this. The Z80A in the socket would have worked with a 4MHz clock but in this circuit there is absolutely NOTHING to be gained in using it.

Well well! It actually worked when power was finally applied! (after curing the fault I�ve already mentioned.)  Note that the circuit also needs the RESET cap and diode mounted somewhere on the board. As you will see from the picture to the left, they are in the bottom RH corner alongside the blue ceramic resonator. It was about midnight when I took this and I was glad to see it finished!

The two pictures below show the extra oscillator components for anyone interested in using the circuit.

As can be seen by the picture below, the simple �Digital Clock� program used to start off this project needs NO RAM! I�ve left the socket in to demonstrate other more interesting programs that need to use the stack, and require storage outside the CPU�s own registers.