DOWNLOAD Sony KF-E42A10 / KF-E50A10 (serv.man7) Service Manual ↓ Size: 13.15 MB | Pages: 127 in PDF or view online for FREE

These servicing instructions are for use by qualifi ed service personnel only. To reduce the risk of electric shock, do not perform any 
servicing other than that contained in the operating instructions unless you are qualifi ed to do so.

An isolation transformer should be used during any service to avoid possible shock hazard, because of live chassis. The chassis of 
this receiver is directly connected to the AC power line.

!

 SAFETY-RELATED COMPONENT WARNING!!

Components identifi ed by shading and ! mark on the schematic diagrams, exploded views, and in the parts list are critical for safe 
operation. Replace these components with Sony parts whose part numbers appear as shown in this manual or in supplements 
published by Sony. Circuit adjustments that are critical for safe operation are identifi ed in this manual. Follow these procedures 
whenever critical components are replaced or improper operation is suspected. 

After correcting the original service problem, perform the following 
safety checks before releasing the set to the customer:

1.  Check the area of your repair for unsoldered or poorly soldered 

connections. Check the entire board surface for solder splashes and 
bridges.

2.  Check the interboard wiring to ensure that no wires are “pinched” or 

touching high-wattage resistors.

3.  Check that all control knobs, shields, covers, ground straps, and 

mounting hardware have been replaced. Be absolutely certain that 
you have replaced all the insulators.

4.  Look for unauthorized replacement parts, particularly transistors, 

that were installed during a previous repair. Point them out to the 
customer and recommend their replacement.

5.  Look for parts which, though functioning, show obvious signs of 

deterioration. Point them out to the customer and recommend their 
replacement.

6.  Check the line cords for cracks and abrasion. Recommend the 

replacement of any such line cord to the customer.

7.  Check the B+ and HV to see if they are specifi ed values. Make sure 

your instruments are accurate; be suspicious of your HV meter if sets 
always have low HV.

8.  Check the antenna terminals, metal trim, “metallized” knobs, screws, 

and all other exposed metal parts for AC leakage. Check leakage as 
described below.

The AC leakage from any exposed metal part to earth ground and 
from all exposed metal parts to any exposed metal part having a 
return to chassis, must not exceed 0.5 mA (500 microamperes). 
Leakage current can be measured by any one of three methods.

1.  A commercial leakage tester, such as the Simpson 229 or RCA 

WT-540A. Follow the manufacturers’ instructions to use these 
instructions.

2.  A battery-operated AC milliampmeter. The Data Precision 245 

digital multimeter is suitable for this job.

3.  Measuring the voltage drop across a resistor by means of a VOM 

or battery-operated AC voltmeter. The “limit” indication is 0.75 
V, so analog meters must have an accurate low voltage scale. 
The Simpson’s 250 and Sanwa SH-63TRD are examples of 
passive VOMs that are suitable. Nearly all battery-operated digital 
multimeters that have a 2 VAC range are suitable (see Figure A).

How to Find a Good Earth Ground
A cold-water pipe is a guaranteed earth ground; the cover-plate 
retaining screw on most AC outlet boxes is also at earth ground. If the 
retaining screw is to be used as your earth ground, verify that it is at 
ground by measuring the resistance between it and a cold-water pipe 
with an ohmmeter. The reading should be zero ohms.

If a cold-water pipe is not accessible, connect a 60- to 100-watt 
trouble- light (not a neon lamp) between the hot side of the receptacle 
and the retaining screw. Try both slots, if necessary, to locate the hot 
side on the line; the lamp should light at normal brilliance if the screw 
is at ground potential (see Figure B).

Trouble Light

AC Outlet Box

Ohmmeter

Cold-water Pipe

Figure A. Using an AC voltmeter to check AC leakage.

Figure B. Checking for earth ground.

The units in this manual contain a self-diagnostic function. If an error occurs, the POWER/STANDBY will automatically begin to fl ash. The number of 
times the LED fl ashes translates to a probable source of the problem. A defi nition of the POWER/STANDBY fl ash indicators is listed in the instruction 
manual for the user’s knowledge and reference. If an error symptom is diffi cult to reproduced use the Remote Commander to display the record that is 
stored at the internal NVM to specify the cause of the failure.

Diagnostic Test Indicators
When an error occurs, the POWER/STANDBY will fl ash a set number of times to indicate the possible cause of the problem. If there is more than 
one error, the POWER/STANDBY will identify the fi rst of the problem areas. If the errors occur simultaneously, the one that corresponds to the fewest 
fl ashes is identifi ed fi rst.

Results for all of the following diagnostic items are displayed on screen. (No error has occurred if the screen displays a “0”.)

Panel/Lamp

Temperature

 2 times

- No picture/No sound

- Panel or Lamp temperature is too high.
- Temp sensor connector is 
  not attached securely.
  (CN7020 on HB Board, 
   CN7180 on S2 Board)

- Check ventilation

Lamp 

Cover/Position

3 times

- No picture/No sound

- Lamp is not inserted correctly (T2 board)
- Lamp cover is not closed (T1 board)
- Detection switch on the
  T1 board or T2 board is damaged

- Re-insert the Lamp
- Re-close the cover
- Change the board

Fan stopped

4 times

- No picture/No sound

- Fan (1-4) power is not rotating.
- Fan connector is not attached securely.
  Fan wires or harnesses caught.

- Clean fan to remove dust, 
  check Fan Regs on AGA Board
- Check connector CN8002 
  on AGA Board

Lamp driver

5 times

- No picture/No sound - HV regulator (Lamp driver) is not working

- Check B_12V output from 
   GTA Board
- Check the thermal fuse 
  near the lamp

Low B error

6 times

- No picture/No sound

- Low B (B_12V) is not supplied 
  (GTA Board) 

- Check AU_VCC from GTA Board
- Check the connection from the 
  AGA Board or GTA Board

Speaker Protection

Audio Error

7 times

- No picture/No sound

- K Board not working
  Fuse blown out 
   (PS3001 on K board)
  IC failure 
   (IC3005 on K board)
- K Board not connected
  Short-circuit of Audio power supply line

- Check AU_VCC from GTA Board
- Check the connection from the 
  AGA Board or GTA Board

D-OVP

8 times

- No picture/No sound

- Low B (B_12V) is over 15V
  (GTA Board) 

- Check B_12V output from 
   GTA Board

Lamp error

LAMP-LED is ON. - No picture/No sound - Lamp for the light source is burned out.

-Replace the lamp

Indicators

Screen

- One flash is not us ed for s elf- diag nosis.

Number of times LED Flash

Lamp cove r

3 times

Fan

4 times

LED ON : 0.3 sec
LED OFF : 0.3sec

LED OFF

3.0 sec

LED OFF

3.0 sec

Example

Diagnosis

Unplug the power cord from the outlet to temporarily stop the POWER/STANDBY lamp from fl ashing.

Self-Diagnostic Screen Display
For failures that are diffi cult to reproduce, or accompany occasional power off and/or picture mute, the Self-Diagnostic screen display is useful to 
specify the cause.

1.  TV must be in standby mode. (Power off).

2.  Press the following buttons on the Remote Commander within a second of each other: 

 

DISPLAY   

Channel 

5      

  Volume  -  

  POWER

 

 

 

 

NOTE:  This differs from the method of accessing service mode which is Volume  +

 

SELF CHECK

1 :

LAMP_ERROR

0

2 :

TEMP_ERROR

0

0

2 :

LAMP_TEMP

0

3 :

4 :

LAMP_ COVER

FAN_ERROR

1

5 :

LAMP_DRIVER

6 :

LOWB-ERROR

0

0

7 :

AUDIO_PROT

8 :

D_OVP

0

1

TIME    :  00105H

MODEL:  KF-E50A10

SERIAL:  XXXXXXX

"1" is displayed when an error is detected one or more times
"0" is displayed when no error has been detected

 

NOTE: To refresh the Self Check menu when all the items are not displayed, press  JUMP  on the Remote Commander. 

3.  Proceed to Viewing the Self-Diagnostic Errors.