Sanyo VHR-VX400 Service Manual page 4

2. Head Output Drop Warning Display
When the STOP button on the remote control is pressed for 10 seconds continuously 10 seconds after play starts, "L" will be
displayed blinking at the minutes position on the tape counter when the head output is lower than the specified value to indicate
an abnormality.
The cause of the abnormality maybe due to drop in the playback output caused by drop in the efficiency of the cassette used or
head clogging. Refer to "Head Playback Output Voltage Check" as a means to judge the abnormality.
I A
I
Head output drop warning display (Tape counter of "Minutes" position)
Head playback output voltage check
Warning
asaette Used
Display
Envelope Detection Output Voltage
Main Cause
Cassette
with normal
playback –
@;:E+05-0g5v Z:ZE
output
Switching pulse
normal
(TP1 83: see Fig. CH-1 CH-2
2-l-1)
Envelope detec- 4V -----------------------------------
tion output
(IC301 Pin 85 or
C3016 HOT side:
"L" blinking
see Fig.
2-l-1) ~V +G$:han
E:!!:z::
Switching pulse
been performed accurately
(TP1 83: see Fig.
CH-1 CH-2
One video head is clogged
Recorded
2-l-1)
One video head has worn out
cassette
(with tabs)
When the average outputvolt-
Envelope detec- 4V -----------------------------------
tion output
(IC301 Pin 85 or
C3016 HOT side:
"L" blinking
see Fig. 2-l-1)
OV ~,,.than z~g:;;;;;
Switching pulse
(TP183: see Fig. CH-1
CH-2
Both video heads are clogged
2-l-1)
Both video heads have worn
out
Envelope detec- 4V -----------------------------------
tion output
(IC301 Pin 85 or
"L" blinking
C3016 HOT side:
see Fig. 2-l-1) Ov k~:::~han :Z::z::
Rental
Switching pulse
been performed accurately
cassette
(TPI 83: see Fig.
CH-1 CH-2
One video head is clogged
without tabs)
2-l-1)
One video head has worn out
Some rental cassettes may have extremely low video playback outputs even when both video heads are normal.
As the average output voltage of the two heads maybe less than 0.5V for some, no warning displays will be
shown.
-J
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