STAND-BY POWER SUPPLY TROUBLESHOOTING METHOD
Contents
1. STAND BY POWER SUPPLY TROUBLESHOOTING METHOD 1 INLOW VOLTAGE MODE e discharge capacitors CP062 and CP013 e shunt resistances RP016 through RPO20 with a 10k 1 2 W resistance e power up the frame with a 12VDC input applied through the mains socket The following situation should ensue C1 period 49 767 us C1 Freq I 20 09342 kHz TP020 collector 2 00 V M 10 0 ps C1 period 49 543 us Unstable histogram TPO20base CUES 20 18449 kHz Unstable histogram 2 00 V M 10 0 us C1 period 51 439 us Unstable TP020 emitter histogram C1 Freq 19 44036 kHz Unstable histogram 8VSB 2 Volts 13 VSB 3 5 Volts 2 00 V M 10 0 ps NB If nothing happens disconnect the collector of TP020 and check the presence of about 2V6 at the cathode of the Zener diode DP019 This method also works if transistors TP021 023 026 are removed The signals are significantly dampened in case the 8 VSB or 13 VSB is short circuited 2 INNOMINAL VOLTAGE MODE 220 VAC remove module VM4000 to force the permanent working of the STAND BY power supply The following situation should ensue C1 period Ne ay ay 17 310 us C1 Freq 57 77009 kHz bu 9 90 V M 10 0 us TP020 collector 8 VSB 8 Volts 13 VSB 13 Volts VERIFICATION e Check whether TP026 is not short circuited
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