Nokia 920C Service Manual
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720C/920C 5-15 Troubleshooting5-1 Parts Level TroubleshootingNotes: 1. If a picture does not appear, fully rotate the brightness and contrast controls clockwise and reinspect.2. Check the following circuits.• No raster appears: Power circuit, Horizontal output circuit, H/V control circuit, and H/V output circuit.• High voltage develops but no raster appears: Video output circuits.• High voltage does not develop: Horizontal output circuits.5-1-1 No Power SupplyCheck and replace FG601, D601,IC661, IC662.Done.Repeating start? Check and replace D601, D604, D663,Q632, and Q664.NoYesIC601 Pin 1 waveform is right? Check and replace IC601,IC602, IC604.YesNoIC602 and IC604are right? Replace parts and verify voltages.YesNoNormal operation Replace Main board.YesYesNoWAVEFORMS11 544 V (IC601, #1)CH1 P-P = 544 V CH1 RMS = 332.4 VVerify voltages. |
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