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2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:34 am
by Tony
The exact order of assembly will depend on the preference of the builder but with SMD components and this PCB it may prove easier to cover as many pads as possible to make placing the smaller components a little easier. I would start with the 3-legged beasties.
A soft heatproof work mat will help as you'll be soldering onto both sides of the board alternately. Apologies for the slightly hairy PCB!.
Start with the MMBTA92 transistors which provide the nixie anode switching. These will be marked '2D, on a black antistatic strip of 5 3-legged plastic squares':
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 5:54 pm
by Tony
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 5:57 pm
by Tony
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:02 pm
by Tony
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:07 pm
by Tony
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:11 pm
by Tony
The 2x 75V zener doides now, these are copper coloured glass cylinders with metal ends on a black antistatic plastic strip of 2. Make sure they're fitted with the black polarity band facing the same way as shown in the photograph:
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:27 pm
by Tony
Now a modification before going any further. See the post here for further information:
viewtopic.php?t=155&f=36
It's under the resistor in the previous pictures but you can see where the PCB has been cut. Cut through this track as it's now connected to the HV supply by that resistor.
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:30 pm
by Tony
Now that's done we need to add the resistor that replaces it. You need the 2x 470r (marked 471) resistors on a paper strip of 2x black rectangles:
Form a bridge using solder or a wire offcut between these 2 pads:
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:31 pm
by Tony
Followed by the HV ceramic capacitors. These are large beige rectangles which are on a clear plastic strip of 2:
You'll need to put some hot glue or similar on these once the clock is finished and working as they tend to buzz due to the piezoelectric effect of the ceramic material.
Re: 2 - PCB Assembly
Posted: Fri Dec 01, 2017 6:33 pm
by Tony
One small 91r resistor, this supplies 3.9v to the IR receiver. It's on a cream paper strip of one and marked '910' :