Panasonic NE-1252, Service Manual

Page: 12 / 36

12
7 Test Mode
7.1. Component test procedure
7.1.1. High voltage transformer
1. Remove connections from the transformer terminals and
check continuity.
2. Normal (cold) resistance readings should be as follows:
Secondary winding Approx. 80
Ω
-120
Ω
Filament winding Approx. 0
Ω
Primary winding Approx. 0
Ω
-3
Ω
7.1.2. High voltage capacitor
1. Check continuity of capacitor with meter on highest OHM
scale.
2. A normal capacitor will show continuity for a short time,
and then indicate 9M
Ω
once the capacitor is charged.
3. A shorted capacitor will show continuous continuity.
4. An open capacitor will show constant 9M
Ω
.
5. Resistance between each terminal and chassis should be
infinite.
7.1.3. Magnetron
Continuity checks can only indicate an open filament or a
shorted magnetron. To diagnose for an open filament or
shorted magnetron.
1. Isolate magnetron from the circuit by disconnecting the
leads.
2. A continuity check across magnetron filament terminals
should indicate one ohm or less.
3. A continuity check between each filament terminal and
magnetron case should read open.