AL-800H Instruction Manual
24
Periodic Maintenance
The high voltage present on various parts of the amplifier will attract dust and dirt. The high voltage areas
at the bottom of the plate choke and the plates and insulators of the air variable capacitors should be kept
dust free. These areas should be inspected periodically, especially if the amplifier is operated in a dusty
environment. These areas may be inspected by unplugging the line cord and waiting a few minutes for the
power supply capacitors to discharge. The high voltage should then be checked with the internal
multimeter by placing the meter switch in the HV position.
WARNING:
High voltages can kill!!! Accidental contact with the voltages in this amplifier can be
lethal!
For your personal safety please observe the following precautions:
1.
NEVER
defeat the interlock.
2.
NEVER
remove the cover with the amplifier connected to the power line.
3.
ALWAYS
allow the capacitors to discharge for several minutes
after
unplugging the amplifier and
before
removing the cover.
4. ALWAYS
select the high-voltage (HV) function of the Multimeter to check the high voltage potential.
Do
not
remove the cover if voltage is indicated.
5. ALWAYS
ground the tube anodes (outer metal surface) to the chassis before touching anything inside
the amplifier.
6. ALWAYS
be cautious of heat. Many components inside the amplifier operate at high temperatures.
7.
NEVER
make any unauthorized component or circuit modifications to this product. The
only
acceptable source for modifications is Ameritron or a source approved by Ameritron. Unauthorized
modifications almost certainly will
increase
the risk of equipment failure or personal injury.
The cover should be removed and a low value (40 to 500 ohm) two-watt or larger resistor should be secured
to the chassis. The other end of this resistor should be connected to the tube anode with an insulated clip
lead.
CAUTION:
NEVER ground the anode directly to the chassis without a series resistor. Component
damage may occur from the current surge.
NOTE:
T
his resistor is a safety device that must be installed when beginning service work and
removed when the work is finished.
Dust and dirt can be blown out of the amplifier with a shop vacuum or a high-pressure air hose. A soft
bristle brush dipped in alcohol can be used to clean particularly dirty areas. If the amplifier is operated in a
dusty environment, a non-conductive low- restriction foam air filter can be placed over the ventilation
holes on the left side of the cabinet near the filter capacitors. Placing an air filter over these air inlet holes
will substantially reduce the amount of dust entering the cabinet. Most hardware stores stock suitable air
filter material that are used as replacement filters for window air conditioners.
