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For Authorised Service Agents Only Ref No: 122923101365258BR Date: 01/10/09 TECHNICAL INFORMATION Created by Panasonic UK - Service Group Document Category: Knowledge Base Subject: TV switches on with green led blinking then goes off. Model(s) Affected: TX-26LMD70 TX-32LMD70 Problem / Issue TV switches on with green led blinking , picture appears for split second then set turns off and the cycle repeats. Solution: This is caused by a faulty P pcb. Due to R850 (820K Ohm) gone high in value Hints: When faulty: - the 24V line dips when the backlights come on and at this moment the TV will switch off and on again! This 24 v goes to the AP pcb and produces a reset signal> 24vDET> which resets the DG pcb. The drop in 24v rail was causing continuous DG pcb resets at power up and hence the Continuous power up/down cycle The regulation pin 11 if ic802 is being driven abnormally by a faulty R850 (820K) R850 provides bias to turn on Q807 and hold off Q808 Confidential Page 1 122923101365258BRREV1 If Q808 is not off it can corrupt the regulation line to ic802 ===================================== SERVICE HINTS: The PSU reverse side can be worked on by using the lead: RFKZ0171 to connect P5 > AP2 and leaving the inverter leads connected as attached ===================================== BOOT UP PROCESS OF THESE SETS: At switch on > the DG pcb gets 5v stby (FROM ic3805 on AP PCB), boots up and produces the TUNER SUB control line (3v) > pin 14, P5 connector to turn on psu IC802, and also to turn on the AP pcb sub supplies below> SUB9v (from Q3810) Q3813 > switched 24V sub5v from Q3803 after above rails come up from Ap pcb the TUNER MAIN ON line goes high (from DG pcb > AP4 pin 18) to turn on remaining rails for set operation> 16v > ic3802 (ap pcb) MAIN9V > q3811 (AP PCB) Finally the DG pcb sends out PANEL ON control signal (AP 4 pin 9) to turn on panel 12v from IC3801 > used for LCD video drive pcb failure of the above DG pcb control signals to come up indicate a possible Dg pcb fault Check AP pcb operation as per above boot up process. Sometimes AP pcb may have failed regulators causing boot up problems Confidential Page 2 122923101365258BRREV1