DT207 SimmStick Power Supply & RS-232 I/O

The DT207 Power Supply and RS-232 SimmStick, is simply a 1" SimmStick intended to power standalone applications.

•  Schematic

Parts List

1 x DT207 PCB

1 x 7805 +5 Voltage regulator in TO-220 case.
1 x Suitable heat sink for above Regulator.
1 x Diode Bridge D1 WO2 (or WO4 type)
1 x 2.1mm or 2.5mm DC Input plug. PCB mount.
1 x Capacitor C1 1000uf Electrolytic @25 Volts. 
     (PCB type mount.)

1 x Capacitor C2 .01uf (or .1uf) Ceramic
1 x Capacitor C3 .01uf (or .1uf) Ceramic
1 x Resistor R1 330 .25 watt Red LED 1
1 x Resistor R2 330 .25 watt for Reset Switch.
1 x 5mm Red LED. LED 1 PWR monitor

A Reset switch can be added for CPU control,
This can be a mini 2 pin TACT switch that can have a .2" or a  .3" pattern.

Serial Communications

1 x MAX-232 or equivalent.
4 x 1uf Electrolytic or Tantalum Caps for Max-232. C4 to C7.
1 x DB-9 female right angle PCB mount connector.

It may also pay to install a 16 pin socket for the Max-232, as you may choose to remove it for some configurations.

Apologies, two board faults have been found:

• The tracking isn't correct at the DC input jack. This can be simply overcome by connecting the two pins together as shown by the yellow jumper wire above. This connection can be done with the excess wire leg of a resistor that has been trimmed off. The yellow jumper is used as it can be easily seen and explained.
   
• The three holes provided for the 7805 regulator are very tight, and some regulators will be awkward to fit. This can be overcome by cutting the legs to suit the positioning of the 7805 regulator with or without a heat sink, and soldering to the top side of the board in much the same way as you would do with a surface mount device. Bend the legs at right angles before trimming, so you can gauge were to cut the legs off.

You can also use a small pair of long nose pliers to squeeze the widest part of the pins, so that they will fit through the board. Trim the legs at approximately the correct length before trying to force the pins through the board. Again, bend the legs at right angles before doing the above, so you can gauge were to cut the legs off.