Back to the 2D3 electronics page

Schematic

Parts

*      omit if the PC synchronisation option is not required.
**    not required if RTC option is fitted.
***  RTC option only

Layout

Construction

Construction using my PCB is quite straightforward but there are a few points worth a mention. If  the  RTC chip option has been bought as part of a kit it is best fitted before any other construction, details are here.

1. The two boards are supplied joined together. They can be separated by flexing them along the scored line. As you bend the board you will hear a tearing sound as the glass fibres break. continue to flex the board back and forth until the two halves separate.
2. The board is finished in standard PbSn. It is not lead free. Use lead/tin solder.
3. The MOSFET's tab should be soldered to the board. For best heatsinking try to get the solder to flow right underneath the whole of the tab. This is best done before soldering the leads.
4. The crystal MUST be fitted with an insulator or spaced 1-2 mm from the board.
5. The easiest way to fit the tubes is to slide the insulator to the ends of the leads leaving only 1-2 mm showing. The tube can then be fitted making sure the anode lead is in the hole closest to the rear of the board. The anode can be identified by the white insulation inside the tube.
   Bruce Nadig who built one of my kits suggested an alternative method: "What I did was leave the anode wire at its full length. I then cut the wires immediately adjacent on either side about 2 to 3 mm shorter. The wires next in the circle were then cut about 2 to 3 mm shorter than the first two wires that I cut. I continued on in this pattern until I reached the wires at the front of the tube. These wires would be the shortest. I then installed the longest wire (the anode wire) into its hole. Following that, I installed the two next longest wires. I continued this until all wires were installed. I found this to be easiest for me."