Sanyo VHR-757G Service Manual page 4

Head playback output voltage check
Cassette Used
Cassette
with normal
playback
output
Recorded
cassette
(with tabs)
Rental
cassette
(without tabs)
Warning
Display
Envelope Detection Output Voltage
Envelope detec-
tion output
(IC301 Pin 25 or
R3032 Mark side:
see Fig. 2-1-1)
Switching pulse
(TP 183: see Fig.
2-1-2)
Envelope detec-
tion output
(iC301 Pin 25 or
R3032 Mark side:
see Fig. 2-1-1)
Switching pulse
(TP183: see Fig.
2-1-2)
av
Envelope detec-
tion output ,
(IC301 Pin 25 or
R3032 Mark side:
see Fig. 2-1-1)
Switching pulse
(TP183: see Fig.
2-1-2)
Envelope detec-
tion output
(IC301 Pin 25 or
R3032 Mark side:
see Fig. 2-1-1)
Switching pulse
(TP 183: see Fig.
2-1-2)
t
f__ 0.5~0.95V
t
=¥ More than
0.95V
+ Less than
4 0.5V
Main Cause
When the output voltage differ-
ence of the two channels is 0.5
to 0.95V
¢ The video heads of both are
normal
When the output voltage differ-
ence of the two channels is
more than 0.95V
¢ Tracking adjustment has not
been performed accurately
'e One video head is clogged
¢ One video head has worn out
When the average output volt-
age of the two channels is less
than 0.5V
¢ Tracking adjustment has not
been performed accurately
¢ Both video heads are clogged
¢ Both video heads have worn
out
When the output voitage dif-
ference of the two channels is
more than 0.95V
¢ Tracking adjustment has not
been performed accurately
¢ One video head is clogged
¢ 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 may be less than 0.5V for some, no warning displays will be
shown.
. Cylinder rotation accumulated time display
@
* Press the STOP button on the remote control for approximately 10 seconds and the cylinder rotation accumulated time excluding
the cassette out and standby operation time will be displayed on the "Hours" display in units of 100 hours. ("33" will be displayed
for 10 seconds for 3,200 to 3,299 hours.)
¢ To erase the cylinder rotation accumulated time display, press the RESET button on the remote control during the accumulated
time display.
Display panel
Cylinder rotation accumulated display (Tape counter "Hours" display)