Aiwa HV-FX780 Service Manual page 25

Pin No. Pin Name
23 A.H.S/W 30
24 V.H.S/W 30
25 CAPSTAN PWM
26 DRUM PWM
27 D.V. SYNC.
28 COLOR ROTARY
29 HEAD AMP S/W
30 COMP IN
31 CTL (+)
32 CTL (–)
33 Vss (SERVO)
34 CTL 1
35 CTL 2
36 CTL 3
37 CTL OUT
38 D.FG
39 D.PG
40 C.FG
41 Vcc (SERVO)
42 Vcc (OSD)
43 CV IN
I/O
Output for the audio head switching 30Hz to the Hi-Fi circuits is made by inputting
O
DPG, DFG signal through pin 38, 39 for switching Hi-Fi head. Refer to pin 24.
Pulses output for switching video head A and B.
- Produces PG M.M pulses internally by using inputted DPG, DFG pulses to pin 38,
39.
O - Produces video head switching 30 Hz pulses by sychronizing at edge point of first
PG. M.M.(PG monostable multivibratior)
- Produces audio head switching 30 Hz pulses by synchronizing at edge point of
second PG.M.M.
- Output pulses (PWM waveform) for controlling capstan motor speed and phase;
control feedback voltage which is inputted to the capstan motor driver IC.
O
- Output pulses (PWM waveform) for controlling capstan motor stop and drive during
slow mode.
Output pulses (PWM waveform) for controlling drum motor speed and phase; control
O
feedback voltage which is inputted to the drum motor driver IC.
Provides an output sync signal to prevent the picture from rolling upward or
O
downward, when the video track is not being scanned in the search mode.
O A pulse to control phase of color at Y/C circuit.
O Apulse for switching the HEAD SP and EP on the DRUM.
A reference signal for switching video head (SPA, SPB, EPA, EPB) on the drum in
I
search the mode.
CTL pulse is outputted at recording, CTL pulse is inputted at playback. Functions
I/O which control capstan motor phase at playback, check tape speed, Viss and Real time
counter are performed by using CTL pulse (input/output).
– Servo circuit GND in the µ-COM.
I/O Port for gain (Amp) control of CTL pulse during recording and playback.
D.FG pulse input according to rotation of drum motor.
I Produces Audio/Video Head S/W 30Hz by using these pulses. And it is used as a
comparison signal for speed control of the drum motor.
One D.PG pulse is generated for each rotation the drum motor and inputted to µ-COM.
I When producing Head S/W pulses, D.PG pulse is used as reference point, and it is
used as comparision signal when controlling drum motor phase.
C.FG pulses are generated by the rotating capstan motor and are inputted to µ-COM.
I When checking tape speed and controlling. The capstan motor phase, These CFG
pulses are used as comparison signal.
I Vcc for servo circuit in the µ-COM.
I Vcc for OSD circuit in the µ-COM.
When the OSD display function is activated both video and text are present, when in
I
the EE or PB modes.
33
Description