DON'T FORGET TO SOLDER THE TAB! it acts as a heatsink connection to the PCB and the 2-legged transistors use it as a third termina.
PCB assembly and testing
Re: PCB assembly and testing
Fit T12 (the square black plastic 3 legged part), bending the end 3mm of its legs down 90 degrees to fit in the holes. Make sure it lies flat on the PCB and solder the tab on the top first, then the three legs. Some kits may be supplied with a surface mounted version only having 2 legs - don't worry as the tab provides the third connection.
DON'T FORGET TO SOLDER THE TAB! it acts as a heatsink connection to the PCB and the 2-legged transistors use it as a third termina.
DON'T FORGET TO SOLDER THE TAB! it acts as a heatsink connection to the PCB and the 2-legged transistors use it as a third termina.
Re: PCB assembly and testing
Fit X1 (DHT11, the blue plastic box) with the silver label facing the PCB as shown.
Re: PCB assembly and testing
Now a tricky part - the surface mounted IC4 (small 8 legged black resin square). Only 7 of the pins are soldered and make sure the dimple in one corner faces the bottom right of the PCB as shown. The latest batch of ICs have a bevelled edge to indicate the side with pin 1, with that edge facing you pin 1 is the front leftmost:
Re: PCB assembly and testing
Almost time for the first live test - fit IC1 and IC2 into their sockets as shown:
Re: PCB assembly and testing
Now carefully inspect the board for solder bridges, dry joints and long leads which may have shorted. Check all the components are in the correct places again.....
Now connect a multimeter on a mA range to the holes on either end of the space marked for R28. Connect the USB power supply and switch on, watching the meter. If everything is working the current should be below 30mA and one blue LED will light up - if not switch off quickly and recheck everything.
If it's working after a few seconds more LEDs will light up in different patterns, Waving your hand slowly over the IR LED should cause the patterns to change as different display modes are selected. That's the main part of the PCB built, now the nixies need to be fitted.
A tip to make this a little easier: Starting from the anode wire which is left at full length, cut each wire a little shorter than the last in a spiral pattern. When you feed the wires through the PCB holes this will allow you to position one at a time, rather than trying to feed all 13 through at the same time.
Now connect a multimeter on a mA range to the holes on either end of the space marked for R28. Connect the USB power supply and switch on, watching the meter. If everything is working the current should be below 30mA and one blue LED will light up - if not switch off quickly and recheck everything.
If it's working after a few seconds more LEDs will light up in different patterns, Waving your hand slowly over the IR LED should cause the patterns to change as different display modes are selected. That's the main part of the PCB built, now the nixies need to be fitted.
A tip to make this a little easier: Starting from the anode wire which is left at full length, cut each wire a little shorter than the last in a spiral pattern. When you feed the wires through the PCB holes this will allow you to position one at a time, rather than trying to feed all 13 through at the same time.
Re: PCB assembly and testing
Take the 2x nixies (1x IN-19A and 1x IN-19b) 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, it's a second anode which isn't counted as a real pin and can be removed if preferred.
Take the IN-19b 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:
Now repeat this with the nixie marked IN-19A, in the V4 socket.
Take the 3x IN-14 nixies out of their packing and straighten the wires as before. Fit one into the socket for V3, followed by V2 and V1. You should now have 3 numerical tubes on the left followed by the IN-19A and with the IN-19b on the right.
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 if bumped though in everyday use they will stay in the sockets as the 13 wires combined have quite a tight hold.
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, it's a second anode which isn't counted as a real pin and can be removed if preferred.
Take the IN-19b 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:
Now repeat this with the nixie marked IN-19A, in the V4 socket.
Take the 3x IN-14 nixies out of their packing and straighten the wires as before. Fit one into the socket for V3, followed by V2 and V1. You should now have 3 numerical tubes on the left followed by the IN-19A and with the IN-19b on the right.
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 if bumped though in everyday use they will stay in the sockets as the 13 wires combined have quite a tight hold.
Re: PCB assembly and testing
Nearly time for another power test: Fit the 33uH coil (copper wire spool) into the position marked Coil L1.
This is probably a good time to mention from this point, DO NOT TOUCH the board whilst powered, 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 to the holes on either end of the space marked for R28. Connect the USB power supply and switch on, watching the meter. This time if everything is working the current should be between 300-350mA and one blue LED and one nixie 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, after a few seconds 4 of the nixies should light up, followed by a changing display pattern every few seconds. Now finally fit R28 and let it run for a while before building it into the case.
***R28 is a polyfuse (mustard disc marked f030, may look like a capacitor)
This is probably a good time to mention from this point, DO NOT TOUCH the board whilst powered, 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 to the holes on either end of the space marked for R28. Connect the USB power supply and switch on, watching the meter. This time if everything is working the current should be between 300-350mA and one blue LED and one nixie 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, after a few seconds 4 of the nixies should light up, followed by a changing display pattern every few seconds. Now finally fit R28 and let it run for a while before building it into the case.
***R28 is a polyfuse (mustard disc marked f030, may look like a capacitor)