Board PCB

[Tony]

For this you will need the entire contents of BAG 5 and the 4 base PCBs:

Unpack and sort out the components into seperate piles:

Clockwise from top LH corner:
34x 6R8 resistors
9x 2R2 resistors
4x 1K5 resistors
30g solder
3x PIC10F200 microcontrollers
9x 14V zener diodes
11x 5V1 zener diodes. Be careful not to mix these up with the 14V zeners above or there will be smoke.



Clockwise from top LH corner:
82x 3n3 ceramic capacitors
65x 2N7000 transistors
45x 33u capacitors
9x Ferrite links
65x 10n capacitors.
Nothing to worry about mixing up here.

[Tony]

I recommend leaving the partly built board until last, if you run into problems you'll then have at least one working board to make comparisons with.

Clean one of the PCBs using a polish block or emery paper as you did with the display PCBs then check for any copper whiskers.

Take 2 Ferrite links from the component pile:



Fit them in the locations marked here:





Solder in place and using a good pair of wirecutters trim the leads close to the PCB as there's only 2mm of clearance under here. Note that blunt cutters will cause damage, possibly tearing the copper from the board.

[Tony]

Take 2 2R2 resistors from the component pile:



Fit them in the locations marked here:





Solder in place etc....

[Tony]

Take 1 1K5 resistor from the component pile:



Fit it in the location marked here:





Solder in place etc....

[Tony]

Take 3 5V1 zener diodes from the component pile:



Fit them in the locations marked here:
These are polarised, make sure the band is facing in the same direction as shown.





Solder in place etc....

[Tony]

Take 2 14V zener diodes from the component pile:



Fit them in the locations marked here:
Make sure the band is facing in the same direction as shown. There is a drilling error in one place so you'll have to carefully solder the diode under the PCB.

[Tony]

Connect the board as indicated to a 12V power supply through a mA meter and switch on. The current should be around 4-6mA, if not check for solder bridges or track shorts.

If the current is OK, check the voltage across the marked diode. It should be about 5V, if it's 12V you have probably mixed the diodes up.

Switch off and disconnect the board ready for the next batch of parts.

[Tony]

Take 8 6R8 resistors from the component pile:



Fit them in the locations marked here:





Solder in place etc....

[Tony]

Take 11 33u capacitors from the component pile:



Fit them in the locations marked here:
Again these are polarised so make sure the white band is facing in the same direction as marked in the photograph.





Solder in place etc....

[Tony]

Take 21 3n3 capacitors from the component pile:



Fit them in the locations marked here:





Solder in place etc....