Troubleshooting Visually

Most RC2014 problems can be diagnosed by looking at it.

I appreciate that some of these items may sound blatantly obvious, and I don’t mean to teach you to suck eggs – but it is worth running through this list just to ease your mind.

Without power applied

  • Take a look at every soldered joint.  They should be bright and rounded, and not touching adjacent joints.
  • Are the modules plugged in to the backplane with Pin1 all lining up?
  • Are the main 4 (CPU, ROM, RAM, Serial I/O) modules in slot 3,4,5&6?
  • Are the correct value resistors and capacitors fitted?  Check the individual assembly guides for visual confirmation.
  • Are the correct ICs in the correct sockets?  Note that 74LSxx and 74HCTxx chips are interchangable on the RC2014, with the exception of the clock module, which needs the HCT variety.
  • Is the orientation of the ICs correct?  The notch on one end of the chip should line up with the notch on the silkscreen or the dog-leg on the chip outline
  • Are the IC pins all seated cleanly in the sockets?  Make sure none of the pins are bent underneath the chip.
  • CPU Module – Are the 3 links for BUSRQ, WAIT and NMI in place.  (Either wire links soldered in or header pins with jumpers)
  • ROM Module – Are the 3 jumpers in place between A13-0, A14-0 & A15-0?  This selects bank 0 on the ROM which has BASIC on it.
  • Serial I/O Module – If powering from FTDI connection, is the 5v jumper in place?  If you have MAX232 for RS232 connection, are the capacitors orientated correctly?  Note that with the MAX232 in place, RC2014 will only accept input from the RS232 connection, and should be removed to use FTDI.
  • Pi Zero Terminal Module – Are the jumpers in place to select Pi as the input and output?  Have you soldered the Tx and Rx link on the backplane to enable the slot that it is plugged in to?  Note – The Pi Zero module needs to be used in addition to the Serial I/O Module, it isn’t a replacement for it.
  • Backplane – If you are using slot 1, 2, 7 or 8, have you soldered links or put jumpers on the backplane to bring the signals through to these slots?
  • If powering with 5v from the barrel jack socket, have you soldered a link in place of the regulator?
  • If powering with >5v from the barrel jack socket, have you installed a 7805 regulator and capacitors?  Are the caps orientated correctly.  Have you ensured the back of the 7805 isn’t touching the solder pads underneath it?

 

 

Plug everything in

  • Is power being applied to the RC2014.  The green LED on the backplane should illuminate if it is.
  • Does the reset button kick the RC2014 in to life?
  • If connected to the FTDI connection on the Serial I/O Module, do you have your terminal software (PuTTY, Screen, Teraterm, Minicom, whatever) set to the right com port, speed of 115200bps, 8 data bits, no parity, 1 stop bit.  Carriage returns need a line feed (look for CR+LF setting)
  • Pi Zero Terminal Module – Does the Pi display the “waiting for serial 115200-8-n-1” message?  Push the RC2014 reset button – any different?