Electro-Metrics EM-2115, Instruction Manual

Page: 77 / 278

EM-2115 4.0 SERVICE, MAINTENANCE, CALIBRATION
(EM2115S4-9)
a. Remove the Power Supply Module (A14) 4.2.6. Leave Connector Plugs P4 and
P3B connected to A14J4 and A15A1J3B respectively.
b. Reconnect the receiver to the AC power source.
c. Turn on the unit and measure the voltage on A13J2-d (Remote Connector). The
voltmeter should in12.0 ±0.1 VDC. If not, adjust A14A1-R7.
d. Measure the voltage on A13J2-c (Remote Connector), the voltmeter should indi-
cate -12.0 ±0.1 VDC. If not, adjust A14A1-R12.
e. Measure the voltage on A2TP-2 (RF Tuner), the voltmeter should indicate -6.0
±0.1 VDC. If not, adjust A14A1-R9.
NOTE: Adjustment A14A1-R9 adjusts the output of the -7 VDC
regulator. The -6 VDC is derived from the -7 VDC output
and must be held to the specification limits stated. The
specification range limit for the -7 VDC supply is -6.6 to -
8.0 VDC, if the -7 VDC must be adjusted above these limits
in order to obtain the -6 VDC limits, check for the follow-
ing:
1) Excessive loading on the -7 VDC regulator,
2) Excessive loading on the entire power supply,
3) Component failure comprising either the regulator in
question or other components within the power supply, mi-
croprocessor, RF Tuner, front panel, or other circuitry.
f. The +5.0 VDC regulator does not have an external adjustment. If this supply does
not meet the stated specification limit, check for the following:
1) Excessive loading on the regulator,
2) Excessive loading on the entire power supply,
3) Component failure comprising either the regulator in question or other
components within the power supply, microprocessor, front panel, or other
circuitry.
4.4.2 Detection/Metering Circuitry Adjustment/Verification