Low B+ Error (6X) - Sony KDS-50A2000 Training Manual

Check
Lamp Lamp-ON Voltage
Driver Block JS1/pin 4
*Before Shutdown*
Does
voltage go low
2.2V to
1V?
Yes
Replace
Lamp
Driver Block
1-474-012-11
If the Lamp-On control voltage transitions from 2.2V to 1V then the TV
microprocessor is instructing the lamp driver to turn on. At this point in
the flowchart the lamp driver is receiving its 380V supply voltage and its
Lamp-On voltage, however, the lamp driver does not function (no spark
gap flash). In this case replace the Lamp Driver Board.
If the Lamp-On voltage does not go low (1V), then the problem is with the
TV microprocessor, replace the A1-Board.

Low B+ Error (6X)

Reference Figure 5-7
In most cases, a defect in the power supply output (G-board) causes
this error (6X), particularly a missing 11V output. However, theoretically
a defective TV microprocessor output (AC-Relay voltage) can also cause
this error, and therefore, consider this component when troubleshooting.
The first step is to listen for the number of relay clicks that occur at initial
TVP-23
Replace
A1-Board
No
A-1205-146-A (50")
A-1205-145-A (55")
A-1205-144-A (60")
6X Flash
Pattern
(Low B+)
TV power ON. This will possible provide clues for quick defect isolation.
0
You will be listening for zero, one, or two relay clicks immediately after
the power button is pressed. If zero relay clicks are heard then either
the AC-relay is defective or the TV microprocessor is not send the "AC-
Relay" ON command. Therefore, check the "AC-Relay" voltage test point
(Reference Figure 2-5).
G-Board
Replace
G-Board
A-1186-654-A
This will be one path to possible eliminate the TV microprocessor as a
suspect for the failure. Check for the presents of the "AC-Relay" ON
voltage on the plus side of C6400 on the G-board (Reference Figure 2-
5). This is the switched voltage from the TV microprocessor to turn on the
Main AC relay and in turn the Main Power Supply. The "AC-Relay" voltage
5. Protection Circuits
Is
0, 1, or 2
1
Relay clicks
Heard before
Shutdown
?
2
Reference
Figure 2-5
Check "AC-Relay"
Voltage at C6400
*Before Shutdown*
Is voltage
Yes
0.6V
Present?
No
Replace
A1-Board
A-1205-146-A (50")
A-1205-145-A (55")
A-1205-144-A (60")
54