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LUKas007 · 26 July 2002, 19:08

My A2000 has 8372A Agnus... When I set j101 to 1-2 the Ami has 512KB Chip, when j101 is set 2-3 then Ami has 1MB Chip. So I think this jumper is for downward compatibility with older Agnus revisions.
I've downloaded one scanned page from A2000 manual describing some jumpers and j200 is described as:
This jumper is used to set the light-pen port number. In the 2-3 position, the light pen input will be the FIRE input of the mouse/joystick port 0. With the jumper in the other position, the light pen input will be the FIRE input of mouse/joystick port 1.
The j300 is:
This jumper determines the time base used for the 50/60Hz CIA timer chip. In the normal posistion, the 50/60 TICK clock, based on AC line frequency, is used as a time base. In the alternate position, the verticle sync pulse from the video section is used. The system will not operate properly without one of these clocks.
The copy (as html format) is at: http://www.titan.co.nz/amigaak/AA060161.htm

so the settings on http://www.amiga-hardware.com/a2000.html are a little messed up...
Anyway, jmmijo thanks for posting.

P.S. I dont exactly understand the meaning of the j300

heh...

26 July 2002, 19:08	#5
LUKas007 Registered User Join Date: May 2002 Location: England Age: 45 Posts: 159	My A2000 has 8372A Agnus... When I set j101 to 1-2 the Ami has 512KB Chip, when j101 is set 2-3 then Ami has 1MB Chip. So I think this jumper is for downward compatibility with older Agnus revisions. I've downloaded one scanned page from A2000 manual describing some jumpers and j200 is described as: This jumper is used to set the light-pen port number. In the 2-3 position, the light pen input will be the FIRE input of the mouse/joystick port 0. With the jumper in the other position, the light pen input will be the FIRE input of mouse/joystick port 1. The j300 is: This jumper determines the time base used for the 50/60Hz CIA timer chip. In the normal posistion, the 50/60 TICK clock, based on AC line frequency, is used as a time base. In the alternate position, the verticle sync pulse from the video section is used. The system will not operate properly without one of these clocks. The copy (as html format) is at: http://www.titan.co.nz/amigaak/AA060161.htm so the settings on http://www.amiga-hardware.com/a2000.html are a little messed up... Anyway, jmmijo thanks for posting. P.S. I dont exactly understand the meaning of the j300 heh... Last edited by LUKas007; 26 July 2002 at 19:16.