Beko K1 CHASSIS, Service Manual

2

1. 

SAFETY INSTRUCTIONS

. 

GENERAL GUIDELINES

1.

It is advised to insert an isolation transformer 

in the AC supply before servicing a hot 
chassis. 

2.

Potentials as high as 33KV are present when 
this receiver is in operation. Operation of the 

receiver without the rear cover involves the 

danger of a shock hazard from the receiver 
power supply. Servicing should not be 

attempted by any one who is not competent 

with the precautions necessary when working 
on the high voltage equipment. Always 

discharge the anode of the tube. 

3.

When servicing observe the original lead 

dress in the high voltage circuits. If a short 

circuit is found, replace all the parts which 
have been overheated or damaged by the 

short circuit. 

4.

Always use the manufacturer’s replacement 

safety components. The critical safety 
components marked with 

 on the 

schematics diagrams should not be replaced 

by other substitutes. Other substitute may 

create the electrical shock, fire or other 
hazards. Take attention to replace the 

spacers with the originals. Furthermore where 
a short circuit has occurred, replace those 

components that indicate evidence of 

overheating. 

5.

After servicing, see that all the protective 

devices such as insulation barriers, insulation 
papers, shields and isolation R-C 

combinations are correctly installed. 

6.

When the receiver is not being used for a 

long time of period of time, unplug the 

power cord from the AC outlet. 

7.

After servicing make the following leakage 

current checks to prevent the customer from 
being exposed to shock hazard. 

LEAKAGE CURRENT COLD CHECK

1.

Unplug the AC cord and connect a jumper  
between the two prongs of the plug. 

2.

Turn the receiver’s power switch on. 

3.

Measure the resistance value with an 

ohmmeter, between the jumpered AC plug 
and each exposed metallic cabinet part on 

the receiver, such as screw heads, aerials, 
connectors, control shafts etc. When the 

exposed metallic part a return path to the 
chassis the reading should be between 

4Mohm and the 20Mohm. When the exposed 
metal does not have a return path to the 

chassis, the reading must be infinite. 

LEAKAGE CURRENT HOT CHECK

1.

Plug the AC cord  directly in to the AC outlet. 

Do not use an isolation transformer for this 
check. 

2.

Connect a 2Kohm 10W resistor in series with 

an exposed metallic part on the receiver and 
an earth, such as a water pipe. 

3.

Use an AC voltmeter with high impedance to 

measure the potential across the resistor. 

4.

Check each exposed metallic part and 

check the voltage at the each point.  

5.

Reverse the AC plug at the outlet and repeat 
each of the above measurements. 

6.

The potential at the any point should not 

exceed 1.4 Vrms. In case a measurement is 
outside the limits specified, there is the 

possibility of a shock hazard, and the receiver 

should be repaired and rechecked before it 
is returned to the customer. 

HOT CHECK CIRCUIT

    AC-Voltmeter

TO INSTRUMENTS
EXPOSED 
METALLIC PARTS

Water pipe
  (earth)

          2 K Ohm

                              Figure 1 
 

X-RAY RADIATION WARNING 

The primary source of X-ray radiation in this receiver 
is the picture tube. The chassis is specially 

constructed to limit X-ray radiation. For continued X-

ray radiation protection, replace the tube with the 
same type of the original one. 

CAUTION  
AFTER REMOVAL OF THE ANODE CAP, DISCHARGE THE 

ANODE OF THE PICTURE TUBE AND THE ANODE CAP TO 

THE METAL CHASSIS, CRT SHIELD, OR THE CARBON 
PAINTED ON THE CRT WITH A HIGH VOLTAGE PROBE 

AND MULTIMETER (SELECT VDC) AND THEN SHORT 

CIRCUIT DIRECTLY TO DISCHARGE COMPLETELY