My Module doesn't work

 This evenings Virtual Area Group meeting covered what needs to be done when your MERG Kit does not function after assembly.

Simon West was our presenter and informed us that almost 90% of problems is down to poor soldering techniques. A timely article from Martin Perry has appeared in the December Journal and is well worth reading.

Make sure you have done all the preliminary tests as outlined in the building instructions.

DO NOT plug in IC's until these tests have ben completed.

It is essential that the orientation of components is checked before applying power to the circuit. This is essential for diodes, electrolytic and tantalum capacitors.

Fault finding needs a logical approach and you should note down your results as you proceed.

Have a reason for doing the test and refer to the circuit diagram.

A basic multimeter is essential and does not need to cost a fortune. (About £3.50)

A very decent version is available for under £20.

Do not be afraid to contact other MERG members. There are lots of resources online showing how to solder and operate test equipment.

There is a section in the Knowledgebase area of the MERG website with a subsection on Kits.

Common problems include failure to observe anti static precautions. A good anti static wrist strap with a proper cord and / or a conductive mat with earthing point is useful but if not available you should discharge any static from yourself before touching any electronics.

If the voltage regulator on your circuit is getting hot, you most probably have a short circuit or a failed IC. Don't touch the regulator you can get a nasty burn.  Remove IC's , check solder joins for shorts between pins and power up again. Recheck the temperature.

If things are OK power off again and replace the IC's one at a time in a logical manner.

Damaged IC socket contacts are usually caused by IC pins not being correctly aligned. Pins need to be bent slightly prior to insertion. Look at the socket carefully and look for dark holes as shown below.

This may need a replacement socket or if you are very good at soldering  you can unsolder the individual pin and use a replacement from another unsoldered socket. Turn-pin sockets can be used but are more expensive.

Be aware on terminal block screws that the voltage might not be available by touching the top of the screw if it hasn't been tightened. Check at the receptacle instead.

Simon continued with a real demonstration on his CBUS test unit.

The talk will be available on MERG TV in the future if you have missed this excellent session.