KV-21M1A - Sony TV Service Manual (repair manual). Page 22

— 22 —

The identification of errors within the BE-4A chassis is triggered in 1 of 2 ways :- 1: Bus busy or 2: Device failure to respond to
I  C. In the event of one of these situations arising the software will first try to release the Bus if busy (Failure to do so will
report with a continuous flashing LED) and then communicate with each relevant device in turn to establish if a device is faulty.
If a device is found to be faulty the relevant device number will be displayed through the LED by a Series of flashes which must
be counted (See Table 1)., on fatal errors are reported with this method.

If a fatal error is found, the set will simply stay in whichever state it was when the error occurred, but if a non fatal error occurs
the set will try to continue to operate.

2

                                  Meaning

IC301 not acknowledging I  C transmission, NVM OK.

IC301 FAULT (Not OK) - flags

IC301 - No H Flyback

IC301 - Stack Overflow.

Overvoltage / Overcurrent Protection (Pin 52) high.

IC002 not acknowledging I  C transmission, IC301 OK.

IC002 and IC301 - No I  C acknowledgment.

General I  C Error (SDA or SCL being held low)

(IC301, IC001, IC002, CN001)

2

3

4

5

6

7

8

9

   

2

2

2

2

Flash Timing Example : e.g. error number 3

Stby LED

Note : Deflection System Adjustments should not be carried

out whilst using an NTSC (60Hz) signal, or if the
signal is unlocked.

ON

ON

ON

OFF

OFF