Wanted working A2000 Motherboard

[Darrin]

All A2000 mobo's are capable of displaying both PAL and NTSC displays. Just need a 1mb Agnus chip and you can switch between the modes using software. And IIRC, some (maybe all?) revisions of the mobo even have a system timing PAL/NTSC jumper (50hz/60hz) you can also set for which mode you prefer to be native.

Yep, my ECS A2000 has the PAL/NTSC Agnus which can be set via a jumper.  It was an NTSC board, and required a joint to be cut and then a jumper would toggle it between PAL and NTSC (I leave it set on PAL).  I'll have to check what revision the mobo is and only certain Agnus chips do both PAL and NTSC.

[Darrin]

Where do you find this jumper to switch from PAL to NTSC, and can you answer me what the switch on the back of the machine does, I thought that would switch to PAL etc

The PAL/NTSC jumper is unfortunately located under the PSU, towards the back of the mobo.  I'll have to scan online to look for the instructions I found to do the mod.  I have 2 switched on the back of my A2000:  One is the black on/off switch and the other is for my Amber Card (A2320 card installed in the video slot on the far right).  What switch do you have?

[Darrin]

here:

J102:  This jumper if available configures the A2000 for NTSC, or PAL operation. Agnus 8370, 8372A, 8372AB for example, support switching between NTSC and PAL. Rev 6.4 motherboards and possibly later revisions come with an 8375 Agnus by default which does not support switching. It was made in in separate versions for PAL and NTSC.

My board is a Rev 6.2.

There's a chance that the switch you mention may have been added by the previous owner to turn on/off DF1 or disable extra RAM:

J301:  This jumper is closed to add a second internal floppy drive, open to leave the second floppy out of the main unit box. The Amiga expects an ID bit stream from each floppy drive; this lets it determine the drive type. External floppies have this ID circuitry on board, but as it's not an industry standard capability, it has to be implemented on the A2000 motherboard to save cost on internal drives. Leaving the jumper open prevents the Amiga from seeing the ID sequence.
J500:  This jumper is used to enable the 512k of RAM at $C00000 and the real-time clock. It is normally closed; opening it will disable both this extra RAM and the real-time clock.

[Darrin]

hi Darrin,

Conflicting reports, amber monitor or extra ram I have a ram card in, but may not be functional board and card had rusted slightly until cleaned, but always powers so PSU is working, floppy drives power so some of the motherboard is functional, can only assume capacitors damaged or requires HD card. Was told in one place an Amiga HD 2000 model requires the card or battery to function, and have removed the battery.

My A2000 is missing the battery and works fine so it is not a problem (The A3000 onboard SCSI needs the battery to save it's settings).  The RAM board is either a RAM expansion card like the Supra Corp 8MB card I have, or you have a really old B2000 board (like my first Amiga 2000) where 0.5MB was on the mobo and the other 0.5MB was on a Zorro card.  An Amiga 2000HD model is simply an A2000 with a SCSI card fitted and it will work perfectly well with the HD card removed.  Some SCSI HD cards have extra RAM on them (my A2061 SCSI card has an extra 2MB and a set of jumpers where it can be configured as 2MB, 1MB, 0.5MB or 0).  Also be aware that there is a maximum RAM limit of (IIRC) 8MB you can add via the Zorro 2 slots.  Try adding more and you might find cards fail.  Also, some cards fail if you try and add the maximum 8MB and in those cases you may need to set jumpers on the RAM cards to reduce the RAM).