Philips 7592, Service Manual

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upon automatic reset when content has not changed for 50 consecutive hours
By leaving SDM or SAM via the power switch, the error buffer will not be reset.
Examples:
ERROR: 0 0 0 0 0 0 0 : No errors detected
ERROR: 6 0 0 0 0 0 0 : Error code 6 is the last and only detected error
ERROR: 9 6 0 0 0 0 0 : Error code 6 was first detected and error code 9 is the last detected (newest) error
The contents of the error buffer can also be displayed by use of the “blinking LED” procedure, if no picture is available. See
explanation of “The blinking LED procedure “below.
Error code definition
In case of non-intermittent faults, clear the error buffer before starting the repair, to make sure “old” error codes are not present.
If possible check the entire content of the error buffers. In some situations an error code is only the result of another error code
(and not the actual cause).
Note: a fault in the protection detection circuitry can also lead to a protection.
Error 0 = No error
Error 1 = X-ray protection, E/W protection and/or Beam
X-ray protection, E/W protection and/or Beam; set is switched to protection; error code 1 is placed in the error buffer; the LED
will blink 1 time (repeatedly). If this happens, isolate each circuit to determine the cause. These circuits are:
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x-ray protection – PROTN
If this protection is active, the most likely cause is the LOT. Detection via pin 3 of the signal processor – item 7301.
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EW protection – PROT-UP
If this protection is active, the causes could be one of the following:
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bad contacts of:
- horizontal deflection coil
- linearity coil 5417
- S-correction capacitor 2418/2419
- flyback capacitor 2414/2416
- line output stage
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short circuit of:
- flyback diode 6414
- EW transformer (bridge coil) 5478/5479 or 5474/5475/5476 (item number depends upon the model version)
- EW driver 7470
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High beam current protection - Beam
As the name implies, what causes this protection is a high beam current (bright screen with flyback lines) which is too high.
Check for the presence of the +200V supply to the CRT panel. If the voltage is present, the most likely cause is the CRT
panel or the picture tube. Disconnect the CRT panel to determine the cause. If the +200V voltage is not present, check
R3840 at CRT-panel and R3445 & D6445 on the main chassis.
Error 2 = Vertical protection - VFB
If this protection is active, the cause could be one of the following (most likely in the vertical output stage):
- 7501 is faulty
- poor contact or open circuit of deflection coil
- +13V-VERT and/or -13V not present
Error 3 = Reserved