PPC motherboard links

The PPC has seven option links on its motherboard. Some of them have jumper pins already present; others would need the jumpers soldered on to be used.

LK1-LK3: Language

LK1	LK2	LK3	Language for BIOS messages
Off	Off	Off	English
Off	Off	On	German
Off	On	Off	French
Off	On	On	Spanish
On	Off	Off	Danish
On	Off	On	Swedish
On	On	Off	Italian
On	On	On	Diagnostic mode (English messages; most of the power on self test is skipped)

LK4: Memory size

This link has a jumper on three pins. If it is on the left-hand pair of pins, then the memory size is 512k. If it is on the right-hand pair, the memory size is 640k (the extra memory chips must actually be present on the motherboard!)

LK5: Unknown

According to the service manual, this link has three pins: Ground, +5 Volts, and the NDMACS line (which runs between the bus gate array and the DMA controller). The Ground pin is marked "512K" and the +5V pin is marked "640K". Whether this is a setting that varies with memory size, or whether the service manual is in error, I do not know.

LK6,7: Builtin graphics adaptor fonts

The links affect the built-in MDA and CGA fonts.

LK6	LK7	Font
Off	Off	Normal: Codepage 437
Off	On	Norwegian: Codepage 865
On	Off	Portugese: Codepage 860
On	On	Greek

John Elliott 21 September 2003