Philips BJ2.4U Service Manual

Service Modes, Error Codes, and Fault Finding EN 19BJ2.4U/BJ2.5U PA 5.Repair TipsIn case only one or no lamp unit at all works, probably the+12Vb (12 - 13 V) is not available or the fuse is broken. Checkfor broken MOSFETS or check if they are switched off properlyby the transistors connected to the PWM outputs of themicroprocessor.In case the Ambi Light switches off after two seconds, serialarcing or parallel arcing protection is active. Serial arcingprotection can be excluded by disconnecting the opto-coupler;check for bad solder joints on transformer or lamp units.Parallel arcing protection can be disabled by grounding pin 8 ofthe microprocessor. Usually the switching frequency (normally63 kHz) will then be too high. Possible causes are oneMOSFET of the converter has no gate drive or is broken, orthere is a short-circuit of the output of the transformer.5.3 Stepwise Start-upThe stepwise start-up method, as known from FTL/FTP sets isnot valid any more. The situation for this chassis is as follows:when the TV is in a protection state detected via the Stand-byProcessor (and thus blinking an error) and SDM is activated viashortcutting the pins on the SSB, the TV starts up until itreaches the situation just before protection. So, this is a kind ofautomatic stepwise start-up. In combination with the start-updiagrams below, you can see which supplies are present at acertain moment.Important to know here is, that if e.g. the 3V3 detection fails(and thus error 11 is blinking) and the TV is restarted via SDM,the Stand-by Processor will enable the 3V3, but will not go toprotection now. The TV will stay in this situation until it is reset(Mains/AC Power supply interrupted).The abbreviations “SP” and “MP” in the figures stand for:• SP: protection or error detected by the Stand-byProcessor.• MP: protection or error detected by the VIPER MainProcessor.Figure 5-5 Transition diagramOnActiveSemiStand-byStand-by(Off St-by)OffMains“on”Mains“off”GoToProtection- WakeUp requested- Acquisition needed- No data Acquisition requiredand no POD present - St-by requested- Tact SW pushedWakeUprequestedProtectionWakeUprequestedGoToProtectionPOD*Stand-byNo data Acquisitionrequired andPOD presentdGoToProtecOnly applicable for sets with CableCARDTM slot (POD)tion- WakeUp requested- Acquisition needed- Tact SW pushed- POD Card remove- Tact SW pushedF_15400_095.eps020206*