Atlas 210x, Installation, Operation And Maintenance Manual

Page: 22 / 58

CAUTION
THE GREATEST DANCER TO THE POWER OUTPUT TRANSISTORS IS
OVERHEATING. THE BLACK ANODIZED HEAT SINK IS DESIGNED TO COOL THE
TRANSISTORS ADEQUATELY UNDER NORMAL OPERATING CONDITIONS, BUT AS
WITH ANY ELECTRONIC OR MECHANICAL DEVICE, IT IS UP TO THE OPERATOR
TO MAINTAIN NORMAL CONDITIONS, AND NOT ABUSE THE EQUIPMENT.
THE MAXIMUM SAFE TEMPERATURE OF THE HEAT SINK NEAR THE OUTPUT
TRANSISTORS IS ABOUT 150 DEC. F. THIS IS A TEMPERATURE THAT WILL BE
TOO HOT FOR YOUR FINGERS TO HOLD, SO A GOOD TEST IS TO PUT YOUR
FINGERS ON THE FINS CLOSEST TO THE TRANSISTORS. IF YOU CAN HOLD ON
WITHOUT A LOT OF DISCOMFORT, YOU'RE OK.
OVERHEATING MAY BE CAUSED BY: (A) MODULATING TOO HEAVILY, (B)
MAKING LENGTHY TRANSMISSIONS WITH SHORT RECEIVING PERIODS, OR (C)
RESTRICTION OF AIR CIRCULATION AROUND THE HEAT SINK. IF THE AIR
TEMPERATURE IS HIGH, SUCH AS ON A HOT DA Y, OR IN A HOT PARKED CAR,
COOLING CAPACITY WILL BE REDUCED. A GOOD RULE IS TO CHECK THE HEAT
SINK FROM TIME TO TIME, AND MAKE CERTAIN YOU'RE NOT RUNNING TOO
HOT. BACK OFF ON MODULATION LEVEL, OR SHORTEN TRANSMISSION TIME.
UNDER ABNORMAL CONDITIONS, A SMALL FAN MAY BE DIRECTED AT THE
HEAT SINK. THIS IS AN EXCELLENT IDEA IF SSTV OR RTTY TRANSMISSION IS
CONTEMPLATED.
19