JVC TV-20F242 Service Manual page 49

Tape loading is OK, but unloads
immediately
Whether does a
cylinder rotate or not?
YES
Whether does a head
switching pulse appear
for TP1002 or not?
30 Hz
YES
Whether is a reel
sensor pulse signal
by IC1001 79th pin
and 80th pin or not?
NO
Investigate a reel sensor.
Whether it takes UNREG
NO
12V for CP1005 2nd pin
or not?
When playback, it
takes 1.3V for 5th
pin of CP1005?
Exchange a cylinder unit.
Whether is PG pulse
NO
signal inputed by IC1001
90th pin or not?
Exchange IC1001.
YES
NO
YES
NO
YES
NO
YES
Investigate a power supply
circuit.
Whether does DC 5V pulse
depends on IC1001 76th pin or
not ?
YES
Investigate R1053
andR1028.
NO
49