Sanyo VHR-279E Service Manual page 4

2. Head Output Drop Warning Display
Display. panel
Head output drop warning display (Tape counter "1st digit of Minutes." position)
Head playback output voltage check
Cassette Used
Cassette
with normal
playback
output
Recorded
cassette
(with tabs)
Rental
cassette
(without tabs)
Warning
Display
"L" blinking
"L" blinking
"L" blinking
Envelope Detection Output Voltage
Envelope detec- 4y
tion output
(IC301 Pin 85 or
C3016 HOT side:
see Fig. 2-1-1)
Switching pulse
(TP 183: see Fig.
2-1-1)
Envelope detec-
tion output
(IC301 Pin 85 or
C3016 HOT side:
see Fig. 2-1-1)
Switching pulse
(TP 183: see Fig.
2-1-1)
Envelope detec-
tion output
(1C301 Pin 85 or
C3016 HOT side:
see Fig. 2-1-1)
Switching pulse
(TP 183: see Fig.
2-1-1)
Envelope detec-
tion output
(1C301 Pin 85 or
C3016 HOT side:
see Fig. 2-1-1)
Switching pulse
(TP183: see Fig.
2-1-1)
CH-1 CH-2
- ¥ More than
-¥ More than
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
¢ One video head is clogged
* One video head has worn out
When the average outputvolt-
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 voltage 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.