Chapter 8 MDC-1810P/1820P Series
Trouble Shooting And On Board Servicing
Operation Manual
No transmit
N
Y
N
Y
N
Y
N
Y
N
Is the trigger signal on TP2
(Modulator PCB) normal?
Is any buzz heard from the
Pulse Transformer?
Is 6.3 V applied to the
magnetron heater?
Pulse length A(ns) B(ms)
SP 100
0.5
M1
200
0.67 or 0.77
M2
550
1 or 1.25
LP
1050 2 or 2.5
0 V
5 V
B
A
Waveform on TP2
Is +250 V on J2-1
(Modulator PCB) normal?
Is the Mod-HT fuse F3
normal (not blown)?
Y
Modulator PCB is faulty.
Check for cable connection
between antenna and display.
Modulator PCB is faulty.
Modulator PCB is faulty.
Internal wiring in the Antenna
unit or Power Supply in the
Display unit is faulty.
The magnetron is faulty.
N
Is +24V supply on J1-1 (IF
Amplifier) normal?
Manual tuning is faulty
Y
Internal wiring in the Antenna
unit or Power Supply in the
Display unit is faulty.
N
Y
Y
Does the voltage on J2-3 (IF
PCB) vary from 6 V to 9 V?
N
Is +5 V supply on J2-2 (IF
PCB) normal?
IF PCB is faulty.
IF PCB or LNFE module is faulty.
LNFE module is faulty.
8-16
93142112-00