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Amstrad Mega PC Service Manual

From RetroTechCollection

The MEGAPC3H40 with Games Card / PC14DSM 14" Dual Synch Colour Monitor Service Manual is Amstrad plc's service manual for the Amstrad Mega PC. A note to engineers at the front says it covers the MEGAPC3H40 games card only, that the main CPU unit is the same as the PC7386SX, and that repairs to that section should use the PC7386SX service manual, part no. 273930 (hosted as Amstrad PC7386SX Service Manual). The note adds that the MEGAPC3H40 was manufactured under licence from Sega. The hosted PDF has 33 pages of colour scans at roughly 90 dpi, assembled into one file in 2006, and no text layer.

Contents

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There is no printed contents list. By PDF page:

  • 1: cover
  • 2: Mega PC 386SX specification
  • 3: note to engineers
  • 4: MEGAPC3H40 cabinet, IC and miscellaneous parts lists
  • 5: Mega PC exploded view
  • 6: index sheet for the games card circuits
  • 7–22: games card circuit diagrams (daughter board, Sega/PC games card, PC bus interface, games processor and video interface circuits, decoupling), Amstrad 7000-series drawings dated August and September 1992
  • 23–24: games card PCB, top and bottom views
  • 25: PC14DSM alignment procedure
  • 26–28: PC14DSM main PCB and audio PCB views
  • 29: PC14DSM main schematic
  • 30: PC14DSM cabinet exploded view
  • 31–32: PC14DSM parts lists, with the electrolytic capacitors on page 32
  • 33: lithium battery caution in several languages

What it settles

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  • The Mega PC's main board and power supply are those of the PC7386SX; the parts list gives the same part numbers (CPU PCB main 273894, power supply unit 273888).
  • The games card's main chips: MC68HC000FN8, Z80, Sega 315-5487, YM3812 and YM3014B, NJM2070M amplifiers and a 53.2034 MHz crystal.
  • The front panel's PC/Sega mode switch, reset switch and cartridge detector switch.
  • The PC14DSM alignment procedure, including the mode select signal on pin 15 (high for game mode, low for VGA).
  • The PC14DSM electrolytic capacitor list and its mains fuse (TL 2.5 A 250 V).

What it does not contain

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  • The main board, power supply and drives; see Amstrad PC7386SX Service Manual.
  • Fault-finding charts.
  • Readable component values on the games card circuit diagrams: the scan resolution is too low for them.
  • A circuit for the power supply module.

Pages that cite this document

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Download: Amstrad Mega PC Service Manual.pdf

Source: Sega Retro, File:Mega PC UK Service Manual.pdf.


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