MiniROM Stacking instructions

• Additional precrimped wire for the MiniROM Molex connector
• Non-shorting single deck rotary switch
• Knob for rotary switch
• Stepped drill bit and drill
• Soldering iron (temperature controlled or 25W)
• No clean solder - I suggest Kester 245
• 26 AWG wire strippers
• Flush diagonal cutters
• A clean, flat, static-free work surface

Pin 6 of the small molex connector on the MiniROM is an external ROM enable/select line. Pin 6 is non-functional until the solder jumper SJ1 on the bottom of the MiniROM is moved from the two pads closest to the SJ1 label to the two pads furthest from the SJ1 label. We will NOT be changing the solder jumper for the MiniROM on the bottom of the stack.

The following instructions assume you are using a single deck non-shorting rotary switch. You could also use a SP3T three position ON-ON-ON toggle switch if you only want to support 3 ROMs.

1. Remove the A/B ROM select switch S1 from the front panel of the Miniwave.
2. Desolder the three wires from the switch.
3. Using a stepped drill bit increase the size of the hole in the front panel for the A/B select switch to accept the rotary select switch.
4. The wire connected to S1-1 at the rear edge of the Miniwave selects socket U10. Solder this wire to position 1 of the rotary switch.
5. The wire connected to S1-3 selects socket U9. Solder this to position 2 of the rotary switch.
6. The wire connected to S1-2 is ground. Solder this to the common connection of the new switch.
7. For each additional MiniROM you stack in U9 do the following:
   • Using a soldering iron move the solder bridge on SJ1 on the bottom of the MiniROM to the side away from the SJ1 label.
   • Insert the spare wire into position 6 of the Molex connector that connects to the MiniROM.
   • Solder the wire connected to pin 6 to the next available position on the rotary switch.