DM300c/DM400c/DM475 Service Manual (SV61801 Rev. D)
Personal Safety (continued)
Don't un der es ti mate the danger of shock: 1 mA (1/1000 amp) is un com-
fort able; 5 mA is dan ger ous —you may jump back and be injured; 12
mA causes hand muscles to con tract, so you can not free your self; 24
mA has proven fatal; and 100 mA (1/10 amp) is likely to be fa tal.
Use the right tools for the job. A tool which slips can cause a short—or a
shock. Don't reach into a circuit with metal tools, or while wearing rings
or a watch. Even in low voltage cir cuits, a metal object can short circuit
two terminals. When work ing on live cir cuits, use tools with in su lat ed
handles and try to keep your tool hand grounded.
Don't bypass safety devices, particularly fuses. Three-wire outlets (120
VAC) are designed to ground equipment to make it safe. If a hot wire
shorts to a grounded frame, the only result is an open fuse. If a hot wire
shorts to an ungrounded frame, the frame itself be comes hot and po-
ten tial ly dangerous. A fuse is a weak link in a circuit, de signed to break
down before any thing else does. The maximum safe cur rent in a circuit
is de ter mined by the de sign ers. Too large a fuse can pass excessive
current, dam ag ing expensive equipment.
For electrical fires, use Type C, BC or ABC extinguishers only. Don't use
soda acid or other liq uid stream extinguishers. They will damage elec tri-
cal equipment and present a shock hazard to the user.
Digital equipment can be easily damaged or destroyed by static charg-
es. Mi cro pro ces sors and other integrated circuits con tain tiny transistors
not much more than a mil lionth of an inch across, which operate at 5 to
Be extremely careful when lifting heavy equipment. Follow the guide-
a. Squat to lift and lower. DO NOT bend at the waist.
b. Keep your low back bowed in while bending over.
c. Keep the weight as close to you as possible.
d. Bow your back in and raise up with your head first.
e. If you must turn, turn with your feet, not your body.
Never jerk or twist!
g. Put the weight down by keeping your low back bowed in.
h. Keep your feet apart, staggered if possible.
Wear shoes with non-slip soles.
Get help if you need it.
Introduction • 1