Manual for V7550

Manual for V7550

Brand: LG logo LG

Category: Monitor

Document Type: Manual

Language: EN

Uploaded: Nov. 21, 2025, 8:37 p.m.

Manual Publish Date: 2003-02-01

  • Power/LED: Controls power; LED illuminates when on.
  • Right Adjustment: Navigates menus clockwise or increases adjustment levels.
  • Left Adjustment: Navigates menus counter-clockwise or decreases adjustment levels.
  • Select: Launches OSD, selects functions/adjustments, and exits menus.
  • Hot Key (Left): Displays Contrast menu without OSD.
  • Hot Key (Right): Displays Brightness menu with OSD.

Troubleshooting and error codes

ProblemTroubleshooting Steps
1. NO POWER (POWER INDICATOR OFF)CHECK FUSE OK? (F901) YES: CHECK C908 VOLTAGE? (AC120V: 160VDC, AC220V: 304VDC) YES: CHECK IC901 PIN 6 WAVEFORM (SQUARE WAVE COMES OUT?) YES: CHECK D941, D942, D951, D961, D962, D971 VOLTAGE? YES: TROUBLE IN Q903, Q952, Q951, Q942, Q941 NO: TROUBLE IN FUSE (F901) NO: TROUBLE IN D900 NO: TROUBLE IN IC901 NO: TROUBLE IN D941, D942,D951, D961, D962, D971
2. NO IMAGE (NO CHARACTER)CHECK IC302 PIN 18(5V)? YES: CHECK IC302 PIN 5, 6, 7? YES: CHECK IC302 PIN 19, 20, 21 ? YES: CHECK IC303 PIN 4 (80V) PIN 8 (12V)? YES: CHECK IC303 PIN 1, 2, 3 ? YES: CHECK R, G, B CATHODE VOLTAGE? YES: TROUBLE IN CRT SOCKET NO: TROUBLE IN P302 5V LINE NO: TROUBLE IN PC SIGNAL, P301 SIGNAL CABLE NO: TROUBLE IN IC302 NO: TROUBLE IN P303 12V LINE/ 80V LINE NO: TROUBLE IN IC303 NO: TROUBLE IN R331~R333, L311~L313 D307~D315. IC304
3. NO RASTER (NO VIDEO, POWER INDICATOR ON)CHECK POWER INDICATOR GREEN or AMBER? AMBER: DPM MODE (NO H and/or V SYNC) GREEN: CHECK D712 ANODE (-160V)? YES: CHECK G1 VOLTAGE? (-70V~-90V) YES: CHECK CDT HEAT VOLTAGE? (6.3V) YES: TROUBLE IN CDT NO: TROUBLE IN D712 NO: TROUBLE IN Q799 NO: TROUBLE IN D941, Q942, Q941
4. NO HORIZONTAL DEFLECTIONCHECK Q706? YES: CHECK B+ VOLTAGE (50V)? YES: CHECK T701(FBT) PIN 2 (60~150V)? YES: CHECK Q705 COLLECTOR WAVEFORM? YES: TROUBLE IN T701, P701 NO: TROUBLE IN Q706 NO: TROUBLE IN 50V LINE NO: TROUBLE IN Q719, Q720, IC701, D710 NO: TROUBLE IN Q705
5. TROUBLE IN H-LINEARITY (UNBALANCED OF H-LIN.)CHECK IC401 PIN 5, 6, 7? YES: CHECK Q711~Q716? YES: CHECK L703? YES: TROUBLE IN C722, C723, C726, C729 NO: TROUBLE IN IC401 (MICOM) NO: TROUBLE IN Q711~Q716 NO: TROUBLE IN L703
6. NO VERTICAL DEFLECTION (ONE HORIZONTAL LINE)CHECK IC601 PIN 3 (15V+)? YES: CHECK IC701 PIN 12, 13? YES: TROUBLE IN IC601, V-CIRCUIT NO: TROUBLE IN R603 NO: TROUBLE IN IC701
7. TROUBLE IN DPM (OFF MODE FAILURE, NO OFF MODE.)CHECK IC401 (MICOM) PIN 30, 31 (H/V INPUT) SIGNAL? YES: H/V SYNC CHECK IC401 PIN 13 WAVEFORM? (12MHz, 5V) YES: CHECK IC401 (MICOM) PIN 27? YES: SEE DPM TABLE CHECK B+ LINE (6.3V,15V+)? YES: TROUBLE IN PC NO: INPUT H/V SYNC SIGNAL NO: (DPM: 0V) NO: CHECK PC, (PC IS NOT GOING INTO DPM OFF MODE) NO: TROUBLE IN X401 NO: TROUBLE IN IC401 (MICOM) NO: TROUBLE IN Q941, Q942, Q951, Q952,
8. NO DEGAUSSING (DEGAUSS ON THE OSD MENU MUST BE PRESSED.)CHECK IC401 PIN 1 (OV)? YES: CHECK Q953 COLLECTOR (15V) VOLTAGE? YES: CHECK P902 ? YES: CHECK RL901? YES: TROUBLE IN TH901, DEGAUSSING COIL NO: TROUBLE IN IC401 (MICOM) NO: TROUBLE IN Q953 NO: TROUBLE IN P902 NO: TROUBLE IN RL901
9. NO TILT (NO ROTATION)CHECK IC401 PIN21 WAVE FORM? YES: CHECK 15V LINE AND 6.3V LINE ? YES: CHECK Q503 COLLECTOR VOLTAGE? YES: TROUBLE IN P501, TILT COIL NO: TROUBLE IN IC401 (MICOM) NO: TROUBLE IN 15V LINE, 6.3V LINE NO: TROUBLE IN Q501~Q503
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