3- PCB Assembly - Nixies

Tony
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3- PCB Assembly - Nixies

Post by Tony »

Take the 2x nixies (1x IN-19B and 1x IN-14) out of their packing and straighten the wires, spreading them out slightly to match the diameter of the socket. If any are uneven or slightly longer than the others you can trim them a little to match - but not too much. They're already cut to approximately the right length before being packed.

Note the white ceramic paint on one of the wires inside the tube, at the back. This is the anode and must face directly to the back of the PCB when fitted. Ignore the short wire stub at the front of the IN-19, it's a second anode which isn't counted as a real pin and can be removed if preferred.

Take the numerical nixie tube from the pack of 2:

Starting with that anode wire, fit it into the topmost hole of the socket in the V5 position, follwed by one wire in sequence into each hole. Make sure the white-topped anode lead is still in the correct place, it's easy to slip one place whilst fighting (or fitting) it in. Push it down carefully into the socket pins until it sits on top of the LED - this acts as a spacer holding it above the PCB in the correct place. (You can fit them in any order you're happy with, I usually work from right to left).

This is shown on the thermometer PCB but the sockets are used in an identical way in the clock:

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Take the 3x IN-14 nixies out of their packing and straighten the wires as before. Fit one into the socket for V4, next to V5 and fit the IN-19B tube into the V3 socket, follwed by the remaining 2x IN-14 nixies in V2 and V1. You should now have 2 pairs of numerical tubes separated by a symbol tube in the centre.

Once you're certain they're in the right places and are vertically aligned you may wish to solder 2-3 of the wires into the socket pins to prevent them being dislodged, though in everyday use they will stay in the sockets as the 13 wires combined have quite a tight hold.
Tony
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Joined: Tue Jul 24, 2012 8:05 pm

Re: PCB Assembly - Nixies

Post by Tony »

Nearly time for another power test: Fit the 20nH coil (copper wire spool) into the position marked Coil L1.

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This is probably a good time to mention from this point, DO NOT TOUCH the board whilst powered and allow 30-60 seconds after switching off before handling it, it's generating 180V+. It's at a low current it will still bite and could be dangerous in the wrong circumstances (Note the wrong circumstances are probably when you'll touch it).

Connect the mA meter again to the space marked for R13. Connect the USB power supply and switch on, watching the meter. This time if everything is working the current should be between 250-300mA and the blue LEDs and nixies will light up - if not switch off quickly and recheck everything, mostly around T12,C6 and the resistors/transistors behind the nixies.

If everything went OK you should now have a display similar to 00+00 with flashing decimal points and a colon cycling between + and -. Now finally fit the 'polyfuse', a light brown resin disc marked 'XF030' and let it run for a while.

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Tony
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Joined: Tue Jul 24, 2012 8:05 pm

Re: PCB Assembly - Nixies

Post by Tony »

The final component is the memory backup battery. Power down the clock and wait about a minute. Take the 0.47F capacitor out of its packing and bend the pins so they're pointing down, at 90 degrees to the base, ready to insert into the PCB. FIt it into the place marked C2, the band on the case top is the negative and faces the front.
Later kits will have different shapes/sizes of capacitor but are fitted in the same way.

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Tony
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Re: PCB Assembly - Nixies

Post by Tony »

Reserved.
Tony
Site Admin
Posts: 955
Joined: Tue Jul 24, 2012 8:05 pm

Re: PCB Assembly - Nixies

Post by Tony »

Before building it into the case, cut a piece of heatshrink sleeving about 1/2" long and slip it over the IR LED D1. The idea is to form a light pipe between it and the case lid to prevent reflections confusing the detector.

If you have the BUTTON version, this step can be ignored.

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