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IBM 5153 Color Display Service Manual (Sams)

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The IBM 5153 Color Display Service Manual (Sams) is Howard W. Sams & Co.'s Computerfacts service data for the IBM 5153 Personal Computer Color Display, the CGA monitor sold with the IBM PC and XT. The hosted scan has 20 pages, several of them fold-out sheets. It is a third-party publication, not an IBM manual, and it is the only document on the wiki that gives component values for the 5153; IBM's Options and Adapters section has a specification and one logic diagram with no parts list.

Contents

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  • Schematic of the complete monitor with designators and values, split across the main board, CRT socket board, power supply board and AC input board, with the high-voltage range printed on it.
  • Waveforms and DC voltages at test points. Sams took the waveforms with a triggered scope and an RGB pattern generator, and the voltages from ground, except those the schematic marks as measured from isolated ground.
  • Terminal guides, resistance measurements, GridTrace location guides and a placement chart for each board, with photographs of the boards.
  • Troubleshooting aid (a symptom chart) and troubleshooting text for the power supply, horizontal, vertical, sync and raster circuits.
  • Preliminary service checks and disassembly instructions.
  • Miscellaneous adjustments: B+, horizontal hold, horizontal and vertical centring, colour temperature, purity and convergence.
  • Parts list: semiconductors with replacement cross-references (Sams SK and other brands), the fuse, the DC-to-DC converter transformer T802, a miscellaneous list and cabinet parts.

The notes on the schematic read: "Capacitors are 50 volts or less, 5% unless noted. Electrolytic capacitors are 50 volts or less, 20% unless noted. Resistors are 1/2W or less, 5% unless noted."

What this manual does not contain

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  • A tabulated capacitor list. Capacitor values are printed on the schematic only, so a recap list has to be read from the drawing, using the notes above for anything unmarked.
  • Coverage of any monitor other than the 5153.
  • IBM's own service procedures. The fault-finding is Sams' generic method for the circuits it traced.

What it settles

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  • High voltage range at the CRT anode: 20.5 kV to 21.5 kV.
  • B+ adjustment: connect a DC meter to TP91, low side to ground, and adjust B+ Adjust Control R851 for +115 V.
  • Power supply checks: AC line fuse F801 (4 A 250 V slow-blow in the parts list); if it has blown, check bridge rectifier diodes D801 to D804. Check for 120 V AC at the output connector of the AC input board, and check coil L804 if it is missing. Then disconnect the DC output connector from the power board and check for 115 V across it.
  • The troubleshooting text expects 153 V at the cathode of D801 and 115 V at the cathode of D815, measured from isolated ground.
  • Colour controls: blue drive R506, green drive R536; red, blue and green background R577, R517 and R547; screen control R999B; horizontal hold R409.
  • Manufacturer part numbers for the CRT (type 370RKB2-TC14, supplied with yoke, 8529290), degaussing coil (8654275), power cord (8529158), signal cable (8529334), front and rear covers (8529285, 8529286) and knobs (8529287 to 8529289).

Pages that cite this document

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Download: IBM 5153 Color Display Service Manual (Sams).pdf

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