Firstly, re-read the assembly guide and see if there’s something you have missed. You don’t have to follow the guide exactly – but if you have deviated from the guide or implemented your own ideas, just double check that you know
- Are all the ICs of the correct part type, and the correct orientation within the socket?
- Give all the joints a visual inspection – Any solder bridges between pins? Or dodgy looking joints?
- Do any of your ICs have bent pins? It is very easy to accidentally bend a pin when inserting into sockets.
- Does the power LED come on when plugged in? If so, is 5v across the power pins of each of the ICs?
- Have you checked the jumper settings?
- Have you selected the correct serial port on your terminal software? If you are using the TTL port, is it set to 115200, 8, N,1? If you are using the RS232 port, are you using 9600, 8, N,1? Are you sure your IDC-to-DB9 cable is using DTK pinout?
- Try re-seating the RAM, ROM and CPU.
- Push the reset button again. Did that work?