AG-TL750E, AG-TL750B - Panasonic Provideo Service Manual (repair manual). Page 16

1-10

CP601

16E

Loading motor and drum motor do
not rotate. When a cassette tape is
not inserted, warning message “E-
01” is displayed. When a cassette
tape is inserted, warning message
“E-02” is displayed.

CP801

16C

The information is not displayed in
the front panel FDP.

CP802

17D

Operate on is impossible. Drum
motor does not rotate. When a cas-
sette tape is inserted, warning mes-
sage “E-02” is displayed.

Do not leave the unit without restoring the power supply after
the lithium battery has been replaced with the power cord un-
plugged, as this causes the backup current to flow continuously
and the lithium battery life will be reduced. Be sure to turn the
power ON after replacing the lithium battery.
The unit incorporates a function for storing the date of a lithium
battery replacement  in the memory. After replacing the lithium
battery, also be sure to execute this function by referring to “7.
BATTERY” in section 1.3.3

When the power supply to the unit has failed due to an electrical
power failure or the unplugging of the power cord, this unit uses
the lithium battery to back up the CPU (IC601 on the MAIN board)
in order to protect the clock operation and set data. Typically a
lithium battery is capable of backing up the memory data for about
2 years.When the lithium battery voltage drops below 2.85 V, this
unit displays an error message “E-10” to notify the replacement
timing. When the lithium battery is replaced with the power cord
unplugged, the CPU will be reset: In this case, the time setting of
the unit after the battery replacement is reset.

IC607 on the MAIN board is an EEPROM capable of electrical
erasure/write operations. This EEPROM stores the following
data.
(1) Hour meter data

Data as displayed under item “HOUR METER” in the SERV-
ICE MENU, and the “HOUR METER” data in the user menu.

Data of the adjustment items displayed under items “SERVO
ADJUST” and “EVR ADJUST” in the SERVICE MENU.
When EEPROM is replaced, reset the adjustment data of
the EVR ADJUST before performing all the adjustments
shown in the following tables.

1

 SERVO ADJUST

3.4.1

SW point adjustment

3.4.2

V-lock adjustment

3.4.3

Slow tracking preset adjustment

3.4.4

Skew adjustment

2

 EVR ADJUST

3.5.1

AGC level adjustment

3.5.3

Sub-emphasis input level adjustment

3.5.4

White & dark clip adjustment

3.5.5

Carrier & deviation adjustments

3.5.6

S-VHS ET SP REC FM level adjustment

3.5.7

S-VHS  SP REC FM level adjustment

3.5.8

Pilot burst level adjustment

3.5.9

S-VHS PB Y level adjustment

3.5.11

S-VHS ET SP REC color level adjustment

3.5.12

S-VHS SP REC color level adjustment

Data of the history of the last 4 emergencies as displayed
under item “EMERGENCY HISTORY” in the SERVICE
MENU.

Data set under item “FUNCTION” in the SERVICE MENU,
and setting data in the user menu.

The MAIN board has circuit protectors as shown in Fig. 1-6.

Table 1-6 shows symptoms when each circuit protector wire is
disconnected.

This unit uses a lithium battery to back up the microcomputer
(IC601 on the MAIN board). Therefore, in case the microcom-
puter runs away, simply unplugging the power cord does not
reset it but it is also required to remove the lithium battery tem-
porarily as described in section 1.2.5

T1

F1

0 1 SW REG.

0 3 MAIN

5 1
DECK
TERMINAL 

CAP. MDA

5 7

P/R

4 3

7

4

3

7

CN51

6V

12V

M12V

CN801

CN604

4

3

CP801

CP802

+5V

+12V

CP601

MDA

13,14

7, 8

DRU. MDA

5 8

CAPSTAN

MOTOR

DRUM

MOTOR

M

M

LOADING
MOTOR

M

(AL5.8V)

(AL12V)

   * For the resetting method of the EVR ADJUST adjustment

data, see section 3.3.2 (7).