BKM 68X alternative input board | CastleMania Games
BKM 68X alternative input board - CastleMania Games
BKM 68X alternative input board - CastleMania Games

BKM 68X alternative input board

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Pre-Order Note

Coupon codes may be disabled for some pre-order and exclusive items.
Pre-order ship dates are estimates and subject to change.
Orders place on/after April 25th will ship late November
(if this date is past-tense, check the support page for updates).

*the above mentioned date is not a promise, it's an estimate based on manufacturing times with an allowance of time for international and domestic shipping.

This project aims to serve as an alternative to the crazy expensive Sony BKM-68X RGB/YPbPr input card for Sony BVM-A monitors like the BVM-A14F5, A20F1, A24E1W and A32E1W (M/U/A).

The card has no aperture circuit so it can only pass the signal straight through to the monitor as it originally is (buffered and level conditioned).

Compared to the original BKM-68X, this has severely better sync handling seemingly.

The list of tested consoles that syncs fine as of revision C1. is:

  • SNES (2CHIP US) 60Hz (CSYNC)
  • SNES (2CHIP EU) 50Hz (Sync on luma)
  • SNES (1CHIP EU, SNSP-1CHIP-01) 50Hz (Sync on luma)
  • Genesis (US) 60Hz (CVBS sync)
  • Genesis 2 (US) 60Hz (CSYNC)
  • Mega Drive (EU) 50Hz (CVBS sync)
  • Mega Drive 2 (EU, DFO) 60Hz (CSYNC)
  • Mega Drive 2 (EU, DFO) 50Hz (CSYNC)
  • Master System (on Genesis through Power Base) 60Hz (CVBS sync)
  • Master System (EU, DFO) 60Hz (CSYNC)
  • Master System (EU, DFO) 50Hz (CSYNC)
  • Master System (EU, VA3, no DFO) 60Hz (59,38Hz) (CSYNC)
  • Master System (EU, VA3, no DFO) 50Hz (CSYNC)
  • Nintendo 64 (NUSJ) 60Hz (THS7314 RGB) (CSYNC)
  • PSone SCPH-101 (EU) (MM3+MFO) 60Hz (RGC CSYNC)
  • PSone SCPH-101 (EU) (MM3+MFO) 50Hz (RGC CSYNC)
  • Wii (EU) 576i 50Hz (YPbPr)
  • Wii (EU) 480i 60Hz (YPbPr)
  • Wii (EU) 480p 60Hz (YPbPr)
  • PS3 (EU) 576i 50Hz (YPbPr)
  • PS3 (EU) 576p 50Hz (YPbPr)
  • PS3 (EU) 720p 60Hz (YPbPr)
  • PS3 (EU) 1080i 60Hz (YPbPr)
  • PC Engine (White), External RGB mod (THS7374, Genesis 2 plug), 60Hz (CSYNC)
  • Analogue Nt Mini 2.0 60Hz RGBS (so CSYNC)
  • Amiga 500 RGBS (PAL) 50Hz (CSYNC)


It is generally recommended to use CSYNC signals at 75 Ohm levels.

Revision history:

C1: Minor layout changes

C: Added mounting screw brackets and shortened board for a PCB front, change switch to LFCSP version

B: Added onboard FPGA, color filter, rerouted signals.

A: Initial version

More information: https://www.immerhax.com

github: https://github.com/skumlos/bkm-68x-simple

*Designed by Martin Hejnfeltskumlos (Skumolos)