Advertisement
While this manual assumes that the reader has a fundamental understanding of
electronics and basic troubleshooting techniques, a review of some of the techniques used
by our staff may help.
1. Visual Inspection - A short visual inspection of the unit under test will often yield
results without the need of complex signal analysis (burnt, or loose components are a
dead giveaway).
2. Self Test - Alesis products that utilize microprocessor control contain built in test
software which exercises many of the units' primary circuit functions. Self test should
always be done following any repair to ensure basic functionality.
3. Environmental Testing - Applying heat and cold (heat gun/freeze spray) will often
reveal thermally intermittent components (Clock crystals, I.C.s, and capacitors are
particularly prone to this type of failure).
4. Burn in Testing - Leaving a unit running overnight often reveals intermittent failures
such as capacitors that begin to leak excess current after a significant amount of time.
5. Cable Checks - Wiggling cables can reveal intermittent failures such as loose cables
or poorly soldered headers. Remember to check power supply cables as well.
6. Flexing the PC Board - Poor solder joints and broken traces can often be found by
pressing the PC Board in various places.
7. Tapping Components - Sometimes tapping on a component (particularly crystals) will
cause it to fail.
8. Power Down/up - Turning the unit off and back on rapidly several times may reveal
odd reset and/or power supply failures.
9. Reset Threshold - A Variac (variable transformer) can be used to check reset
threshold levels. This can be particularly useful in helping customers with low line
problems.
10. Compressors - Using a compressor/limiter is often helpful when attempting to solve
low level noise problems, as well as assisting with DAC adjustments.
11. Sweep Tests - Sweep generators are very useful in checking the frequency response
envelopes of anti-aliasing filters.
12.
Piggybacking - Piggybacking I.C.s is particularly useful when troubleshooting
large sections of logic. This is especially true when working with older units.
C4 Service Manual
General Troubleshooting
10-22-02
V1.01
Advertisement
