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Building an 1806 Screamer II

August 12, 2017


There are the board changes I need to make to accommodate the 74HC132 replacing the 4093 and the CY27C256. The 74HC132 is needed for the higher clock speed and the changes are the same ones I made before. For the CY27C256 ROM It’s basically the same but I’m cutting the trace in what I think will be an easier spot and I’m not initially rewiring pin 1 (VPP) because the data sheet says it’s a “don’t care” unless it’s actually 12V.

Next Steps:

  1. make the trace cuts noted in red
  2. install the small components – resistors, jumpers,capacitors
  3. install the sockets
  4. cut the wide memory chip socket (U2) to allow the narrow(U8) chip to go in
  5.  install socket pins for the narrow chip and resonator
  6. install the 30 pin connector
  7. test all the +V and gnd points for correct voltages
  8. install the resonator and 74HC132 – see if it clocks at 4MHZ, 6MHZ and 8MHZ
  9. install the other ICs checking for smoke
  10. 10 see if the processor will execute code from the wide memory
  11. install the 8 pin connector
  12. try it with the olduino board at 4MHZ.

 

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