Apple1 Prototypecard    Page No.:A17
 
         
      In the second step after i started with the design of the slotexpansionboard - and after i discovered that at the slotedgeconnector the + 12 Volt and - 12 Volt only were present as non stabilized power i revised the availiable amount of power at this point. By definition of the transformator delivered with the original Apple-1  there would only be 1 Ampere availiable. In fact i also had prepared the slotexpansion-board to be able to get the 12Volt positiv and negativ also by choice from an external powersupply but there still was the question open about the use of the expansioncards in different slots. If the card would be inserted in the "on board" slot, that slot would still offer only unstabilized power, because the stabilization would only regulate the power at the slots of the slotexpansion itself. So i decided to also offer the opportunity of populating a stabilization on the card itself - if it was desired to use it within the "on board" slot.

 

In fact at the slot only the +5 Volt is oīffered as stabilized voltage and the -5 Volt is not availiable at all. So i added the opportunity to get that voltage "droping out" from the -12 Voltage branch. In case the card should be used in the slots of the slotexpansioncard there would still be the possibility to hardwire bridges to the +12 Volt regulation and the -12 Volt regulation - but still populating the - 5 Volt, if that powersource would be needed as stabilized voltage.

In the first version for testing purposes i only made a simple trace for proof of the functions, but for the cards that will later be offered for ordering, od course there will be extended thick traces to offer a lot of short wiring from "power-source-rails" of + 5 Volt, - 5 Volt, + 12 Volt and - 12 Volt  to the electronics soldered in the card. And if the options of stabilizing the voltages on the card are used - there is enough space left remaining - to use coolingsinks for the voltageregulators.

Some of the possible uses of the prototypecard might be projects like a PIA-card fot control of a printer with parallelport to printout listings, or a prototypecard with a SIO chip to control either modem or serial printer or the version with the PIA to control external devices with optocopling ICīs or relais. The card permits the freedom to keep off all that kind of experiments or interfaces from the mainboard and the different projects are only limited by the phantasy of the user.

If using wirewrap connectionlins at the 2 rows above of the socketconnectionpads itīs also possible to examine the signals at the slot with "homebrew" connectioncables at an oscilloscope.

  
   
Frontside / populationside  Backside / soldering side
       
  
     
 
     
 ACI  Size compare to expansioncards
 
 		  
         
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