Fault Finding Guide
Repairing a sound mixing console requires specialist skills, but basic Fault Finding is within the scope of any user if a few basic rules are followed.
lGet to know the Block Diagram of your console (see page 29).
lGet to know what each component in the system is supposed to do.
lLearn where to look for common trouble spots.
The Block Diagram is a representative sketch of all the components of the console, showing how they connect together and how the signal flows through the system. Once you have become familiar with the various component blocks you will find the Block Diagram quite easy to follow and you will have gained a valuable understanding of the internal structure of the console.
Each Component has a specific function and only by getting to know what each part is supposed to do will you be able to tell if there is a genuine fault! Many `faults’ are the result of incorrect connection or control settings which may have been overlooked.
Basic Troubleshooting is a process of applying logical thought to the signal path through the console and tracking down the problem by elimination.
lSwap input connections to check that the source is really present. Check both Mic and Line inputs.
lEliminate sections of the channel by using the insert point to
lRoute channels to different outputs or to auxiliary sends to identify problems on the Master section.
lCompare a suspect channel with an adjacent channel which has been set up identically. Use PFL and AFL to monitor the signal in each section.
Insert contact problems may be checked by using a dummy jack with tip and ring shorted together as shown below. If the signal appears when the jack is inserted it shows that there is a problem with the normalling contacts on the jack socket, caused by wear or damage, or often just dirt or dust. Keep a few in your gig tool box.
Wire Link
Dummy Insert Bypass Jack
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