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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).

To Exposed Metal 

Parts on Set

0.15 F

1.5 K 

Ω

AC

Voltmeter

(0.75 V)

Earth Ground

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.

*If a +B overcurrent is detected, stoppage of the vertical deflection is detected simultaneously.  The symptom that is diagnosed first by the 

mircrocontroller is displayed on the screen.

**Refer to Screen (G2) Adjustments in Section 2-4. of this manual.

 

+B Overcurrent 

 

2 times

 

I-Prot 

 

 

4 times

 

IK (AKB)   

 

5 times

 

*One flash count is not used for self-diagnostic.

Turn off the power switch on the TV main unit or unplug the power cord from the outlet to stop the STANDBY/TIMER LAMP from flashing.

The units in this manual contain a self-diagnostic function. If an error occurs, the STANDBY/TIMER LED will automatically begin to flash. The number 

of times the LED flashes translates to a probable source of the problem. A definition of the STANDBY/TIMER LED flash indicators is listed in the 

instruction manual for the user’s knowledge and reference. If an error symptom cannot be reproduced, the Remote Commander can be used to review 

the failure occurrence data stored in memory to reveal past problems and how often these problems occur.

When an error occurs, the STANDBY/TIMER LED will flash a set number of times to indicate the possible cause of the problem. If there is more than 

one error, the LED will identify the first of the problem areas.

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

Power does not turn on 

+B overcurrent (OCP)* 

I-Prot

IK (AKB)

Does not light

2 times

4 times

5 times

2:0 or 2:1

4:0 or 4:1

5:0 or 5:1

• Power cord is not plugged in.
• Fuse is burned out (F601). (A Board)

• H.OUT (Q505) is shorted. (A Board)
• IC1751 is shorted. (CV Board)

• +13V is not supplied. (A Board)
• IC545 is faulty. (A Board)

• Video OUT (IC545) is faulty. 

(A Board)

• IC001 is faulty.  (A Board)
• Screen (G2) is improperly adjusted.**

• Power does not come on.
• No power is supplied to the TV.
• AC Power supply is faulty.

• Power does not come on.
• Load on power line is shorted.

• Has entered standby state after horizontal raster.
• Vertical deflection pulse is stopped.
• Power line is shorted or power supply is stopped.

• No raster is generated.
• CRT Cathode current detection reference pulse       

output is small.

For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confirmed, it is possible to bring up past 

occurrences of failure on the screen for confirmation.

In standby mode, press buttons on the Remote Commander sequentially, in rapid succession, as shown below:

Display  

  Channel  5      

 Sound Volume  -  

 Power ON

Numeral “0” means that no fault was detected.

Numeral “1” means a fault was detected one time only.

Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen during repairs. When you 

have completed the repairs, clear the result display to “0”.

Unless the result display is cleared to “0”, the self-diagnostic function will not be able to detect subsequent faults after completion of the repairs.

To clear the result display to “0”, press buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:

Channel  8 

  ENTER

To quit the entire self-diagnostic screen, turn off the power switch on the Remote Commander or the main unit.

Occurs when an overcurrent on the +B (135V) line is detected by pin 72 of IC001 (A Board). If the voltage of pin 72 of IC001 (A Board) is less than 1V 

when V.SYNC is more than seven verticals in a period, the unit will automatically turn off. 

Occurs when an absence of the vertical deflection pulse is detected by pin 78 of IC001 (A Board). Power supply will shut down when waveform interval 

exceeds 2 seconds. 

If the RGB levels* do not balance within 2 seconds after the power is turned on, this error will be detected by IC001 (A Board). TV will stay on, but 

there will be no picture.

*(Refers to the RGB levels of the AKB detection Ref pulse that detects 1K).

Note that this differs from entering the Service Mode (Sound Volume  + ).

A BOARD

IC001

Y/CHROMA JUNGLE

A BOARD

IC545

V. OUT

A BOARD

IC001

SYSTEM

A BOARD

IC002

MEMORY

IK-AKBIN

FROM

CV BOARD

IC1751 PIN 5

I-HLDWN

FROM

A BOARD

IC561

PIN 7

72

O-LED

REF

I-Prot

IO-BDAT

BDA

DISPLAY

51

3

78

79

53

5

Chassis Assembly

Claw

6 

Screws +BVTP 4X16 TYPE2 TT(B)

Rear Cover

A Board

KB Board

CV Board

1

Unplug  KB  Board    and  2  pin  woofer  connector  and  move  out  of                      

the way.

2

Press on catch tab to release A Board.

3

Disconnect remaining cables to allow A Board to be removed.