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Club L/C Meter Project - Construction Notes and Photos


Construction Notes and Photographs

Read the G4HUP instructions and these notes before starting your kit.

Carefully check and sort the parts, some of the parts have very similar markings but very different values!

Ensure all the resistors and other parts are flat and neat against the board with their markings facing in the same direction - ideally reading left to right. This makes the values easier to check afterwards. The JP2 - Programming header is omitted.

No components are included in the kit for a backlight. LCD's have provision for backlight, so it could be fitted with extra parts.

R12,13 shorted for Meter operation, using link wires.

Install the M links for Meter operation using the supplied hookup wire.

33pf ceramics for the oscillator. You may need to carefully reform the leads so they fit nicely on the board.

10uf caps longer lead is positive, shorter lead negative.

The + symbol on 10uf tantalum bead caps is very small - check carefully. You may need to carefully reform the leads so they fit nicely on the board. It may also be necessary to bend them flat to the board before soldering to reduce the height.

Depending on height it might be an idea to mount the LCD display trimmer on its side.

Install the PIN headers for JP1 and single pins at TP 4 (Ground) , 3 (+9 Volts Unswitched) and TP2 (+9 Volts Switched).

After installing the passive components, install the regulator and triple check the installed components, then connect up 9 Volts to the TP4 (Ground) an 3 (+9 Volts Unswitched). Check you have 5 Volts at pin 2 on the LCD and pin 14 (5th pin down on the right) where the PIC will be. This check should stop your PIC or display from getting damaged if the 5 Volt regulation circuitry is not working correctly!

Install the PIC - NOTE points downwards, be very careful to check the cutout to ensure you have the PIC the right way round before you solder it in!

Install the Relay chip, check orientation carefully.

Spacers (to be supplied) will be needed before the LCD can be mounted.

Switches, the inductor (L1) and capacitors (C6,C7) for the oscillator are to be supplied.

Case options are being investigated.

Measured the LCD bias voltage as 335 mV, useful to know for future reference.

Terminals are soldered on last after fitting into the case. This may or may not be an issue depending on the builders case.

Extra washers and longer bolts are available if the LCD display does not clear the board.

I have sourced some splendid 1% 1nf/1000pf caps, they are big and green and marked 10000n0 - but are the correct value and price! They are for C6 and C7.


Photographs

The following photographs are for additional info and guidence only, stick with the G4HUP manual and the above notes for construction! Also note that I used a ribbon cable to connect the LCD, your LCD is mounted later directly above the board.

Parts
The Board!
Parts
The Board!
Parts
Carefully tin the link wire!
Parts
Blutack to hold the link wire in position
Parts
Wire soldered
Parts
Link wires fitted, component bridges next
Parts
About to solder component bridges
Parts
Component bridges in place
Parts
Resistors
Parts
Neatly solder them
Parts
Checking 4.7K resistor
Parts
Checking 47K resistor!
Parts
Resistors and diodes - note the bands - are fitted.
Parts
Carefully form and fit the capacitors(!) next to the crystal
Parts
Carefully form and fit the capacitors(!) next to the crystal
Parts
Carefully fit the capacitor next to the regulator IC2
Parts
I modified a header so the LCD can be connected using a ribbon cable. Standard kit will not need this!!!!
Parts
More components, then check the 5 Volt supply - before soldering in the PIC!
Parts
Fitted the PIC and ribbon cable for a quick test - Not part of the standard build!
Parts
Fitted the 82uh inductor and the other parts, pressed calibrate and it displays 0pF - Excellent!