[[Category:CPC Internal Components]]
'''Links''' - Amstrad has used a number of LKs (Links) on CPC mainboards and on peripherals like DDI-1 and CPC+ Cartridges. The LKs are simply a piece of wire that is (or is not) installed between two soldering points.
== LK1,LK2,LK3 - Manufacturer ID ==
LK1,LK2,LK3 connect to [[8255|PPI]] Port B, Bit1-3. The links select the manufacturer name (which is displayed by the BIOS in the power-up message). These LKs exist on all CPC mainboards (in CPC Plus/GX4000 /Costdown schematics they are named LK101,LK102,LK103). By default, LK1-LK3 are not installed (except, [[Amstrad]]). Other combinations are LK2 is installed in german Scheider [[Schneider]] models), and LK1+LK2 in australian [[Awa]] models. For more info see [[LK-selectable Brand Names]].
== LK4 - Screen Refresh Rate ==
LK4 (LK104 on Plus/GX4000/Costdown) connects to [[8255|PPI]] Port B, Bit4. The link tells the BIOS whether it should set-up the [[CRTC]] for 50Hz or 60Hz refresh rate.
Default is LK4 not installed (50Hz).
It might be installed in US models, there isn't too much known about whether CPCs were exported to USA.... One source says that the CPC6128 was initially sold ''only'' in USA... Another source says that Indescomp (spanish distributor) produced CPCs with ''Indescomp International U.S.A.'' stickers.
The 60Hz setting may cause compatibility problems with various non-BIOS software. And, due to a BIOS glitch, even with BIOS-based software (see [[Media:S968ap13.pdf|SOFT 968 Appendix 13 (XIII) (Hints Tips and Workarounds)]] for details).
== CPC6128:LK5,LK6,LK8 - Disable 128K RAM Banking ==