In Case Of Difficulty - Heathkit mMATIC SA-5010A Manual

This part of the Manual will help you locate and correct any difficulty which might occur in your
µMatic Memory Keyer. This information is divided into three sections. The first section, "General",
contains suggestions in the following areas:
A. Visual checks and inspection.
B. Precautions to observe when bench testing.
C. How to determine the area of the µMatic Memory Keyer in which the difficulty is
located ("How To Troubleshoot Your Keyer").
D. Locating and correcting both the cause and the effect of a difficulty
("Repairing the Keyer").
The second section consists of a "Troubleshooting Chart". This chart calls out specific problems
that may occur and lists one or more conditions or components that could cause each difficulty.
The resistor R numbers, capacitor C numbers, transistor Q numbers and diode D numbers are
identified in this chart by the same number that are used on the Schematic Diagram. X-Ray Views
are also provided to help you locate the component and test points.
PRECAUTIONS FOR BENCH TESTING
1. Be cautious when testing solid-state circuits. Although transistors and integrated circuits have
almost unlimited life when used properly, they are much more vulnerable to damage from ex-
cessive voltage or current than other circuit components.
2. Be sure you do not short any terminals to ground when making voltage measurements. If the
Probe slips, for example, and shorts out a bias or voltage supply, this could cause damage to
one or more transistors or diodes.
3. Do not remove transistors or integrated circuits while the µMatic Memory Keyer is turned on,
since this could damage the keyer.
HOW TO TROUBLESHOOT YOUR KEYER
If you know which area your trouble is in, apply the "Visual Checks" to that area.
You may also go directly to the Troubleshooting Charts to see if the difficulty you are having is
listed in one of the "Problem" columns. If your difficulty is listed there, check the "Possible Causes"
listed for this problem and apply the "Visual Check" listed to the area of difficulty.
REPAIRING THE KEYER
When you make repairs to your keyer, make sure you eliminate the cause as well as the effect of
the difficulty. If, for example, you find a damaged resistor, be sure you find out what it was
(wiring, error etc.) that caused the resistor to become damaged. If the cause is not eliminated, the
replacement resistor may also become damaged when you put the keyer back into operation.

IN CASE OF DIFFICULTY

GENERAL
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