The XA1541 mini-adaptor

Important notes

  • You definitely need BSV52 transistors and 4.7 kOhm resistors for this adaptor, different parts may make the adaptor inoperable.
  • This is a double-sided board that needs to have the two sides connected via conductive material inside the drilled holes: through-coppering.


You need the following parts to build this adaptor:

  • One solderable 25-pin male plug (PC parallel plug)
  • One printable circuit board of about 4 x 2 centimeters
  • Four BSV52 transistors
  • Four SMD 1206-style 4.7 kOhm resistors

Step 1. Build the board of the adaptor, cut it to shape and drill the holes in it, according to the board diagram (300 DPI resolution): top side and bottom side. Both diagrams show the board as viewed from that particular side. Use through-coppering to connect the two sides through the holes.

Step 2. Build the enhancer bridges, consisting of one transistor and one resistor each, onto the appropriate places. These include the following connections:

Parallel plug Parallel plug
 13, Select   1, Strobe
 12, PaperEnd  14, AutoFeed
 11, Busy  17, SelectIn
 10, Ack  16, Init

The collector of the transistor should be pointing towards the pins in the left column of the table. The base of the transistor should be pointing towards the pins in the right column of the table; this is also the place for the resistor. The emitter of the transistor should be connected to the common ground of the adaptor.

The parts should be soldered the following way onto the board. This diagram shows the top side of the board as viewed from above.

[XA1541 mini-adaptor]

Step 3. Solder and then glue the board between the two pin rows of the parallel plug. The upper side of the adaptor, the one with the electronical components, should be leveled with the longer side of the parallel plug, the one with 13 pins.

Circuit diagram:

[XA1541 mini-adaptor]

You can find the description of all parts used on the diagrams at the legend page.

Source: The Joe Forster-STA homepage