ELECTRONIC EQUIPMENT REPAIR CENTRE : PANASONIC SA-AK350PL CIRCUIT DIAGRAM POWER AMP AND POWER SUPPLY

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PANASONIC AUDIO

PANASONIC SA-AK350PL

CIRCUIT DIAGRAM POWER AMP AND POWER SUPPLY

EEPROM Checksum (ROM Correction)
Purpose: To check for microprocessor firmware version and EEPROM checksum (ROM correction)

Below are the procedures for this mode.
Step 1: Enter into Doctor mode (for more information, refer to section 9.2 on the key operation to enter into this mode.
Step 2: Check for firmware version and EEPROM checksum (By pressing STOP button on main unit followed by “4” and “7” on remote control).
· When entering into DOCTOR MODE, the firmware version and checksum data of EEPROM (if applicable) will appear on FL display. Below is the information on the EEPROM IC (ROM correction) under 3 possible situations:
1. In the case that the correction point existence data is other than 0 (ie. correction file exists), EEPROM checksum display for the microprocessor shall be made after calculating checksum by summing up the content of data area from EEPROM IC.

2. In the case when no EEPROM IC is installed. It display as no display of checksum data

3. In cases that the filename is different even though a EEPROM is installed, or no correction file exists, [NG] shall be displayed (the correction point existence data is set to 0 at this condition).

Note: Microprocessor firmware refers to version number for microprocessor IC located on PANEL P.C.B.. It is subject to change which would be updated accordingly. ROM correction checksum refers to the HEX code that is displayed upon key buttons pressed if an EEPROM is loaded in the unit.

Error code Table Display
Self-Diagnosis Function provides information on any problems occuring for the unit and its respective components by displaying the error codes. These error code such as U**, H** and F** are stored in memory and held unless it is cleared. The error code is automatically display after entering into self-diagnostic mode.

CRS1 Error Code display
CRS1 Error Code display
1. The errors that occured in CRS1 Mechanism can be recalled and displayed, in the order of the occurence under self-diagnostic
for procedures to enter this mode.
· Only the first 5 errors will be memorized (in backup memory). The subsequence error shall be ignored and not memorize. For system with EEPROM as memory backup,memory space in EEPROM is neccesary.
2. To display all error code memorized In CRS1 Self-Diagnostic mode, press [SINGLE CHANGE] to display subsequence error code. It shall repeat after reaching error no. 5.
e.g.:
[1 _ _ _ _ I H M S] → [SINGLE CHANGE]
[2 _ _ _ _ I T O P] → [SINGLE CHANGE]
[3 _ _ _ _ H O M E] → [SINGLE CHANGE]
[4 _ _ _ _ L O A D] → [SINGLE CHANGE]
[5 _ _ _ _ _ U D D] → [SINGLE CHANGE]
3. To clear the error code memory
In CRS1 Self-Diagnostic mode, long press [SINGLE CHANGE] key (2s or more)

Measurement And Adjustments
Cassette Deck Section

Requirements
· Test tape (QZZCFM) (QZZCWAT)
· Normal blank cassette tape (QZZCRA)
· Digital frequency counter
· Oscilloscope
· Electrical voltmeter
· Headphone jack output jig

Setting of Unit
· VOLUME: MAX

Preparations].
1. Remove 4 screws from the mechanism unit to disassemble
2. Connect the headphone jack output to headphone jack.

Tape Speed Adjustment
· Normal speed adjustment (only during forward playback)
(Product reference value: 3,000±90Hz)
1. Connect a frequency indicator.
2. Playback the middle portion of the test tape (QZZCWAT).
3. Adjust the motor screw so that the following output level is produced.
Adjustment Range: 3,000 ± 90Hz (a constant speed)

Bias Voltage Check
1. Connect an electrical voltmeter. (Fig 12) (Fig 9 for location of test point)
2. Set the function to “TAPE” position.
3. Insert a normal blank cassette tape (QZZCRA).
4. While pressing and holding down [REC/PAUSE] button, press [TAPE( PLAY )] button to pause the recording mode. (Repeat pressing the buttons till the recording pause mode is activated.)
5. Check that the output level is within the standard range.
Standard Range: 16 ± 3M