JVC KV-V8 Service Manual Download

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1-6

1.6.3

EMG content description

Note:

EMG contents “E08/E09” are for the model with Dynamic Drum (DD).

Table 1-6-3a

When the mechanism mode cannot be changed to an-
other mode even when the loading motor has rotated
for more than 4 seconds in the loading direction, [E:01]
is identified and the power is turned off.

When the mechanism mode cannot be changed to an-
other mode even when the loading motor has rotated
for more than 4 seconds in the unloading direction, [E:02]
is identified and the power is turned off.

When the take-up reel pulse has not been generated for
more than 4 seconds in the capstan rotating mode, [E:03]
is identified, the pinch rollers are turned off and stopped,
and the power is turned off. However, the reel EMG is
not detected in STILL/SLOW modes.

When the drum FG pulse has not been input for more
than 3 seconds in the drum rotating mode, [E:04] is iden-
tified, the pinch rollers are turned off and stopped, and
the power is turned off.

When the eject operation does not complete in 3 sec-
onds after the start, [E:05] is identified, the pinch rollers
are turned off and stopped, and the power is turned off.
When the cassette insertion operation does not complete
in 3 seconds after the start, the cassette is ejected. In
addition, when the operation does not complete within
3 seconds after the start, [E:05] is also identified and the
power is turned off immediately.

When the capstan FG pulse has not been generated for
more than 1 second in the capstan rotating mode, [E:06]
is identified, the pinch rollers are turned off and stopped,
and the power is turned off.However, the capstan EMG
is not detected in STILL/SLOW/FF/REW modes.

When short-circuiting of the SW power supply with GND
has lasted for 0.5 second or more, [E:07] is identified,
all the motors are stopped and the power is turned off.

When DD tilting does not complete in 4 seconds, [E:08]
is identified, the tilt motor is stopped and the power is
turned off.

When the DD FG pulse is not generated within 2.5 sec-
onds, [E:09] is identified, the tilt motor is stopped and
the power is turned off.

When the supply reel pulse has not been generated for
more than 10 seconds in the capstan rotating mode,
[E:0A] is identified and the cassette is ejected (but the
power is not turned off). However, note that the reel EMG
is not detected in the SLOW/STILL mode.

1. The mechanism is locked in the middle of mode transition.
2. The mechanism is locked at the loading end due to the encoder position

reading error during mode transition.

3. Power is not supplied to the loading MDA.

1. The mechanism is locked in the middle of mode transition.
2. The mechanism is locked at the unloading end due to the encoder posi-

tion reading error during mode transition.

3. Power is not supplied to the loading MDA.

1. The take-up reel pulse is not generated in the FWD transport modes (PLAY/

FWD SEARCH/FF, etc.) because;
1) The idler gear is not meshed with the take-up reel gear;
2) The idler gear is meshed with the take-up reel gear, but incapable of wind-

ing due to too large mechanical load (abnormal tension);

3) The take-up reel sensor does not output the FG pulse.

2. The supply reel pulse is not generated in the REV transport modes (REV

SEARCH/REW, etc.) because;
1) The idler gear is not meshed with the supply reel gear.
2) The idler gear is meshed with the supply reel gear, but incapable of wind-

ing due to too large a mechanical load (abnormal tension);

3) The supply reel sensor does not output the FG pulse.

3. Power is not supplied to the reel sensors.

1. The drum could not start or the drum rotation has stopped due to too large

a load on the tape, because;
1) The tape tension is abnormally high;
2) The tape is damaged or a foreign object (grease, etc.) adheres to the tape.

2. The drum FG pulse did not reach the System controller CPU because;

1) The signal circuit is disconnected in the middle;
2) The FG pulse generator (hall device) of the drum is faulty.

3. The drum control voltage (DRUM CTL V) is not supplied to the MDA.
4. Power is not supplied to the drum MDA.

1. The cassette cannot be ejected due to a failure in the drive mechanism of

the housing.

2. When the housing load increases during ejection, the loading motor is

stopped because of lack of headroom in its drive torque.

Housing load increasing factors: Temperature environment (low tempera-
ture, etc.), mechanism wear or failure.

3. The sensor/switch for detecting the end of ejection are not functioning normally.
4. The loading motor drive voltage is lower than specified or power is not sup-

plied to the motor (MDA).

5. When the user attempted to eject a cassette, a foreign object (or perhaps

the user's hand) was caught in the opening of the housing.

1. The capstan could not start or the capstan rotation has stopped due to too

large a load on the tape, because;
1) The tape tension is abnormally high (mechanical lock);
2) The tape is damaged or a foreign object (grease, etc.) is adhered to the

tape (occurrence of tape entangling, etc.).

2. The capstan FG pulse did not reach the System controller CPU because;

1) The signal circuit is disconnected in the middle;
2) The FG pulse generator (MR device) of the capstans is faulty.

3. The capstan control voltage (CAPSTAN CTL V) is not supplied to the MDA.
4. Power is not supplied to the capstan MDA.

1. The SW 5 V power supply circuit is shorted with GND.
2. The SW 12 V power supply circuit is shorted with GND.

1. The absolute value sensor is defective. (The soldered parts have separated.)
2. The pull-up resistor at the absolute sensor output is defective. (The soldered parts

have separated.)

3. Contact failure or soldering failure of the pins of the connector (board-to-board) to the

absolute value sensor.

4. The absolute value sensor data is not sent to the System Controller CPU.

1. The FG sensor is defective. (The soldered parts have separated.)
2. The pull-up resistor at the FG sensor output is defective. (The soldered parts have

separated.)

3. Contact failure or soldering failure of the pins of the connector (board-to-board) to the FG sensor.
4. The power to the sensor is not supplied. (Connection failure/soldering failure)
5. The FG pulse is not sent to the System Controller CPU.
6. The tilt motor is defective. (The soldered parts have separated.)
7. The drive power to the tilt motor is not supplied. (Connection failure/soldering failure)
8. The tilt motor drive MDA - IC is defective.
9. Auto-recovery of the DD tilting cannot take place due to overrun.

1. The supply reel pulse is not generated in the FWD transport mode (PLAY/

FWD SEARCH/FF, etc.) because;
1) PLAY/FWD or SEARCH/FF is started while the tape in the inserted cas-

sette is cut in the middle;

2) A mechanical factor caused tape slack inside and outside the supply

reel side of the cassette shell. In this case, the supply reel will not rotate
until the tape slack is removed by the FWD transport, so the pulse is not
generated until then;

3) The FG pulse output from the supply reel sensor is absent.

2. The take-up reel pulse is not generated in the REV transport mode (REV

SEARCH/REW, etc.).
1) REV SEARCH/REW is started when the tape in the inserted cassette

has been cut in the middle;

2) A mechanical factor caused tape slack inside and outside the take-up

reel side of the cassette shell. In this case, the supply reel will not rotate
until the tape slack is removed by the REV transport, so the pulse will
not be generated until that time;

3) The FG pulse output from the take-up reel sensor is absent.

3. The power to a reel sensor is not supplied.

FDP

CONTENT

CAUSE

Presupposing the presence of the control pulse output in the PLAY mode, when the value obtained by mixing the two V.FM output
channels (without regard to the A.FM output) has remained below a certain threshold level for more than 10 seconds, [E:C1] or [E:U1]
is identified and recorded in the emergency history. During the period in which a head clog is detected, the FDP and OSD repeat the
“3-second warning display” and “7-second noise picture display” alternately.

EMG code : “E:C1” or “E:U1” / FDP : “U:01” / OSD : “Try cleaning tape.” or “Use cleaning cassette.”

The head clog warning is reset when the above-mentioned threshold has been exceeded for more than 2 seconds or the mode is
changed to another mode than PLAY.

EC1 or EU1:
Head clog warning

E0A:Supply Reel

Pulse EMG

E07: SW Power

Short-Circuit

EMG

E06: Capstan FG

EMG

E05: Cassette Eject

EMG

E04: Drum FG

EMG