Hi Res Version of Motherboard Front (1752 x 940)
Hi Res Version of Motherboard Back (1752 x 940)

MegaRamHD is an IDE controller and fast RAM expansion connects to the side expansion slot of A500/A500+. It can be expanded with up to 8MB of 16-bit fast ram using standard 30-pin SIMM modules. It also allow you to connect one IDE hard drive (low profile, 1 inch height max). Elsat.device is installed in the MRHD's ROM and doesn't allow you to connect more than one IDE device. This limitation can be fixed with a special patch, probably available on Aminet. Hard drives formated with the MegaRamHD CAN'T be read with standard amiga scsi.device & vice versa because it doesn't use the standard RDB format.

The MegaRAM has a pass through for other units

Jumpers

 JP2 JP1    JP2 JP1     JP2 JP1     JP2 JP1
 
  o   o      o [o]          [o]  o      [o] [o]
 [o] [o]    [o][o]          [o] [o]     [o] [o]
 [o] [o]    [o] o            o  [o]      o   o

  2 MB       4 MB            8 MB           AMNESIA

2 MB = one pair of 1MB SIMM's
4 MB = two pairs of 1MB SIMM's
8 MB = one pair of 4MB SIMM's
AMNESIA = memory switched off  

Thanks to Gary Bliter