Sanyo DP50749-02 Service Manual

Sanyo DP50749-02 Service Manual Manual pdf 1 page image

SANYO: DP50749-02 & DP50719-00 12/28/10with PANASONIC 50" PLASMA PANEL (MD50H12NBC) p#1SYMPTOM: TV's GREEN POWER LED WILL NOT REMAIN ON 2009-9Bnote: Unplugging any power cable from the SMPS to isolate the defective PCB will not work on this Panasonic panel.Unplugging any of the power cables will cause the SMPS to shut down.a) Unplug LVDS Cable (40 pin connector) from Main to Digital "D" Bd. (D5 connector) behind Main:This will eliminate the Main Bd., and see if the SMPS will power ON automatically, and remain ON.Plug the AC Cord to power (do not push the Pwr Key on the TV) and see if the SMPS will power ON.If the SMPS powers ON and remains ON, then the Main Bd. should be tried. If the SMPS continues to shutdownthen resistance checks (#1-#12) below should be done.note: This panel has a self test mode, and unplugging the LVDS starts the self test. No raster is displayed,because a special jig is needed to activate the raster & video.b) If the Base has ever been removed from the TV, the metal leg could have cut the Flat Ribbon andPCB underneath the leg. Please see page #4.RESISTANCE CHECKS TO POSSIBLY ISOLATE DEFECTIVE PCB Location of connectors is1) Is pin #1 or #2 (60V) of (P35 connector) shorted to chassis Gnd? on page #2yes, shorted = PDP Panel N/Gnot shorted = go to step #2 Please re-install all PCB mounting2) Is Pin #5 or #6 (5V) of (P25 connector) shorted to chassis Gnd? screws whenever a board isyes, shorted = go to step #3 changed, and before re-testingnot shorted = go to step #4 the TV. The ground screws are3) Disconnect (p25 connector) needed to prevent damage to theIs Pin #5 or #6 (5V) of (P25 connector) shorted to chassis Gnd? PCB.yes, shorted = SMPS N/Gnot shorted = go to step #4 After working on TV, if it has4) Disconnect (SC20 connector) several horizontal lines or bars,Is pin #30 (5V) of SC20 connector shorted to chassis Gnd? please try reseating the flatyes, shorted = SC Bd N/G ribbons going to the SU & SD Bds.not shorted = go to step #55) Disconnect (SS23 connector)Is pin #1 (5V) of SS23 connector shorted to chassis Gnd?yes, shorted = SS Bd N/Gnot shorted = go to step #6Reconnect P25, SC20, & SS23 Connectors6) Disconnect (SC2 connector)Is TPVSUS (SC2, pin #1, 193V) on SC Bd. Shorted to chassis Gnd?yes, shorted = SC Bd. N/Gnot shorted = go to step #77) Reconnect SC2 and disconnect (SS11 connector)Is TPVSUS (SS11, pin #1, 193V) on SS Bd. Shorted to chassis Gnd?yes, shorted = SS Bd. N/Gnot shorted = Power ON TV, and check TPVSUS on SC Bd. for 193V before shutdownIf no output, = SMPS N/GIf 193V OK is before shutdown, SC Bd. may be defective (can not be sure)Reconnect SS11 Connector8) Is TPSC1 (143V) shorted to base pattern of SU/SD Bd?Base Pattern Test Points are on attached page (please do not use chassis Gnd)yes, shorted = go to step #9not shorted = go to step #11, not necessary to check #9 - #109) Disconnect SU41 connectorIs TPSC1 shorted to base pattern of SU/SD Bd?not shorted = SU Bd. may be defectiveyes, shorted = go to step #1010) Reconnect SU41 and disconnect SD42 connectorIs TPSC1 shorted to base pattern of SU/SD Bd?not shorted = SD Bd. may be defectiveyes, shorted = SC Bd. may be defective11) Measure resistance across C956 (143V across cap.) on SD Bd.. If resistance is only a few ohms, the SD BD. is defective.12) Measure resistance across C907 (143V across cap.) on SU Bd.. If resistance is only a few ohms, the SU BD. is defective.If you can not find anything wrong and you suspect the panel is shorted, you can unplug the eight flat ribbons from the panelto the buffer bds. (SU & SD) and see if the SMPS will remain ON. You can not unplug the flat ribbons to the Sustain Drive(SS) Bd. (if you unplug the flat ribbon/s to the SS Bd. the panel will shut down). If all PCBs and other connections are OK, theSMPS will power ON and have all voltages with these ribbons unplugged. If the SMPS should remain ON with the ribbonsunplugged, you should re-connect them and then verify that the SMPS still shuts down when they are connected.note: The SMPS will remain ON, if one or more of the flat ribbons are unplugged from the panel to the buffer bds. (SU & SD),if the PCBs and other connections are OK.