A2000 mainboard jumper settings

LUKas007 · 24 July 2002, 23:33

Ello

I'm looking for the default settings of jumpers on A2000 mainboard (at the moment I use rev6.2B), especially j101, j200, j500... Is there anyone who could tell me exactly the purpose of these three jumpers or better every jumper of the A2000 mainboard?

jmmijo · 25 July 2002, 00:10

Here you go, try this link out, scroll down a bit for the info you want

http://www.amiga-hardware.com/a2000.html

LUKas007 · 25 July 2002, 00:48

Thanks

Heh, but if I ask a question here it means that I've checked out the net before... I mean I would like to have someone's own words description of the jumpers, as I dont understand decription of the j101 and j200 from the pages on the net... besides there are more jumpers on the A2000 mainboard than the pages on the internet decribe...
Btw, the pages on the net dont specify the default configuration

as I put my A2000 together using three damaged units, messed up with the jumpers and don't remember now what were standard settings...

jmmijo · 25 July 2002, 01:15

J101 determines the CHIP ram addressing, are you using the OCS or ECS chipset, meaning have you the original or the enhanced Agnus chip installed?

Not sure, then look at the chips part number on top; if it's an 8370/8371 then it's the OCS Agnus only supports 512K chip ram. If the number is 8372/8372A then it supports 1MB of chip ram. If the number is 8372B then it supports 2MB of chip ram. Any of the 8372 series Agnus chips could be considered part of the Enhanced Chip Set. This should help determine what the J101 config should be. Not sure what the default setting should be however

Now to determine the addressing, the easiest way would be to use SysInfo which will show you this info. This way you can see where the address is and compare it to the current J101 config and write it down for future reference

If you swap around the J101 config and then boot up the machine and run SysInfo again, this address should have changed, if indeed you have one of the ECS Agnus chips!

The J200 jumper determines the machines clock settings to either NTSC/60Hz or to PAL/50Hz. I like the line frequency setting better but of course I'm not sure which way this is either

It's been a few years since I've had an A2000, I wish I could give you some more help on this

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...

Hanzu · 04 August 2016, 10:42

Quote:

Originally Posted by LUKas007

... or better every jumper of the A2000 mainboard?

I know this is an old thread, but so is Amiga and this thread still appeared to my search when I wondered the same things as the OP and I would like to clear some doubts with this and also explain J900 which puzzled me:
http://www.amigawiki.de/doku.php?id=...:a2000b#jumper

breech · 14 October 2017, 11:39

Quote:

Originally Posted by Hanzu

I know this is an old thread, but so is Amiga and this thread still appeared to my search when I wondered the same things as the OP and I would like to clear some doubts with this and also explain J900 which puzzled me:
http://www.amigawiki.de/doku.php?id=...:a2000b#jumper

The source is Dave Haynie himself, but noone queried him on jumper J900 unfortunately. Can anyone here think of a use of it?

Quote:

J101 Select A19/A23 for second Agnus RAM bank select
J102 Enable NTSC mode on ECS Agnus, disable test on 512K Agnus
J200 Select port 0/port 1 lightpen
J300 Selects LINE/VSYNC TICK source
J301 Enables 3.5" 880K ID code for DF1:
J500 Enable for decoding of $00Cxxxxx as RAM
J900 Enable Chip RAM slowdown during DMA

On the same topic, I have a Pal rev 4 which is OCS - except for the 1mb fat Agnus. when i jumper it for NTSC i can select 1mb or 512k no problems but when I jumper it for PAL + 1mb get a grey screen. Anyone know what i'm doing wrong?

Maybe i should restore the Fat lady 8371 because I've kept a note that it ships as 512 but is 1mb capable.

Malakie · 13 October 2021, 03:02

Hi,

Anyone know what CN606 on the A2000 mainboard is? Is it power? Is there a power connector like that on the main board that can be used for devices with the small power plug like floppies have? I have a small HD that can use that type power connector so am wondering if there is a way to do so on the A2000 mainboard if possible.

Jope · 13 October 2021, 07:00

It has the interrupt signals on it, not a power connector.

You would have to take power from a zorro slot if you want a sturdy power rail.

Malakie · 13 October 2021, 16:46

Quote:

Originally Posted by Jope

It has the interrupt signals on it, not a power connector.

You would have to take power from a zorro slot if you want a sturdy power rail.

So there is no power connector I can use like you find on PC mainboards then... well shit.

Jope · 14 October 2021, 06:54

A regular PC motherboard won't have power outlets either, only inputs.

I've seen some non-standard power outlets in brand name PCs over the years, but it's not really something you can guarantee to find on every motherboard.

24 July 2002, 23:33	#1
LUKas007 Registered User Join Date: May 2002 Location: England Age: 45 Posts: 159	A2000 mainboard jumper settings Ello I'm looking for the default settings of jumpers on A2000 mainboard (at the moment I use rev6.2B), especially j101, j200, j500... Is there anyone who could tell me exactly the purpose of these three jumpers or better every jumper of the A2000 mainboard?

25 July 2002, 00:48	#3
LUKas007 Registered User Join Date: May 2002 Location: England Age: 45 Posts: 159	Thanks Heh, but if I ask a question here it means that I've checked out the net before... I mean I would like to have someone's own words description of the jumpers, as I dont understand decription of the j101 and j200 from the pages on the net... besides there are more jumpers on the A2000 mainboard than the pages on the internet decribe... Btw, the pages on the net dont specify the default configuration as I put my A2000 together using three damaged units, messed up with the jumpers and don't remember now what were standard settings... Last edited by LUKas007; 25 July 2002 at 00:55.

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.

13 October 2021, 03:02	#8
Malakie Registered User Join Date: Jan 2020 Location: Wisconsin, USA Posts: 194	Cn606 Hi, Anyone know what CN606 on the A2000 mainboard is? Is it power? Is there a power connector like that on the main board that can be used for devices with the small power plug like floppies have? I have a small HD that can use that type power connector so am wondering if there is a way to do so on the A2000 mainboard if possible.

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25 July 2002, 00:10	#2
jmmijo Junior Member Join Date: Jan 2002 Location: PDX Age: 62 Posts: 2,395	Here you go, try this link out, scroll down a bit for the info you want http://www.amiga-hardware.com/a2000.html

25 July 2002, 01:15	#4
jmmijo Junior Member Join Date: Jan 2002 Location: PDX Age: 62 Posts: 2,395	J101 determines the CHIP ram addressing, are you using the OCS or ECS chipset, meaning have you the original or the enhanced Agnus chip installed? Not sure, then look at the chips part number on top; if it's an 8370/8371 then it's the OCS Agnus only supports 512K chip ram. If the number is 8372/8372A then it supports 1MB of chip ram. If the number is 8372B then it supports 2MB of chip ram. Any of the 8372 series Agnus chips could be considered part of the Enhanced Chip Set. This should help determine what the J101 config should be. Not sure what the default setting should be however Now to determine the addressing, the easiest way would be to use SysInfo which will show you this info. This way you can see where the address is and compare it to the current J101 config and write it down for future reference If you swap around the J101 config and then boot up the machine and run SysInfo again, this address should have changed, if indeed you have one of the ECS Agnus chips! The J200 jumper determines the machines clock settings to either NTSC/60Hz or to PAL/50Hz. I like the line frequency setting better but of course I'm not sure which way this is either It's been a few years since I've had an A2000, I wish I could give you some more help on this

13 October 2021, 07:00	#9
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	It has the interrupt signals on it, not a power connector. You would have to take power from a zorro slot if you want a sturdy power rail.

14 October 2021, 06:54	#11
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	A regular PC motherboard won't have power outlets either, only inputs. I've seen some non-standard power outlets in brand name PCs over the years, but it's not really something you can guarantee to find on every motherboard.

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