SECTION IV
MAINTENANCE
4- 1 INTRODUCTORY and detergent, then recoat with the special
oil, Filter Coat No. 3, made by Research
This section contains instructions for adjust- Products Gorp., Madison 10, Wisconsin. In-
ing and servicingthe 150A Oscilloscope. The spect the air filter often when the 150A is in
150Ais constructed so that each of the major constant use.
circuit sections is physically located on a
single etched circuit board, except for the
Main Vertical Amplifier which utilizes two
4-3 REMOVING THE CABINET
separate chassis. The material in this sec-
tion is divided as the circuit sections, each
section having a complete set of adjustment The 150A chassis and panel are removed from
the cabinet by removing the four retainer
instructions, and at the rear of the manual, screws on the rear of the cabinet and sliding
a schematic and a voltage-resistance dia-
gram. The material in this section is as the chassis forward out of the cabinet.
follows :
4-2 Replacing the Air Filter 4-4 CONNECTING FOR 230-VOLT POWER
4-3 Removing the Cabinet LINES
4 -4 Connecting for 230 -Volt Power
Lines The 150A is normally shipped from the fac-
4-5 Servicing Etched Circuits tory with the dual primary windings of the
4-6 Tube Replacement Chart two power transformers connected in parallel
4-7 Isolating Troubles to Major Sec- for use on 115-volt a-c lines. The windings
tions can easily be reconnected in series for use
4-8 Adjusting the Low-Voltage Sup- on 230-volt power if desired. The primary
plies connections to both power transformers are
4-9 Adjusting the RF High -Voltage identical, and each requires the same change
in connections. To reconnect the primary
Supply
4- 10 Replacing and Adjusting the CRT windings of TZ and T3 for use on 230 volts,
4-11 Adjusting the Calibrator on each transformer disconnect the jumpers
4- 12 Adjusting the Main Horizontal which join terminals 1 to 4 and 2 to 5. Con-
Amplifier nectl0-ohm diskthermistors RT301 to T2 and
4- 13 Adjusting the Ext. Horiz. Input RT302 to T3 between terminals 4 and 5. Re-
Preamplifier place the 6-amp fuse with a 3-amp fuse and
the 150A can now be operated from 230 volt
4- 14 Adjusting the Sync Circuit
4- 15 Adjusting the Preset Sensitivity lines with no change in operation.
of the Sweep Generator
4- 16 Calibrating the Sweep Generator 4-5 SERVICING ETCHED CIRCUITS
4- 17 Adjusting the Gainand Frequency
Response of the Main Vertical Figure 4-1 illustrates how to replace elec-
Amplifier trical parts on etched circuits.
4- 18 Adjusting the 9 152A Dual Trace
Amplifier When servicing etched circuits, DO NOTpush
or pull wires in such a way as to raise the
wiring from the board.
4-2 REPLACING THE AIR FILTER
When soldering leads on the etched board,
use a 50 watt iron or smaller. Apply heat
The air -filter element in the 150A is a renew- sparingly to the leads on the part to be re-
able type. It is retained in the bottom of the placed, not to the wiring on the board.
instrument cabinet by two bullet catches, and
is removed by pulling straight down. To re- Before installing new parts, clean holes to
new the filter element, wash in warm water receive new part without forcing. Have new
4- 1 |