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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Abou27 on April 06, 2004, 10:32:13 PM

Title: A4000 not working with A3640
Post by: Abou27 on April 06, 2004, 10:32:13 PM

Hello all,

I am having problems with an A3640(rev 3.1) board that I bought for my A4000/030 (Buster 11 and 3.1ROMS).  I have changed jumper J100 on the MB from INT to EXT and the J100 on the processor card is set to enable MAPROM.  When I power up I just get a light grey screen.  Also, both the HD and floppy access lights come on and stay on permanently.  I am unable to get the start-up screen on reset or power-up.  I have tried switching back to the original processor card and everything works fine.  Do I have a dodgy A3640 or is there any other explanation?  I have looked at Warren Block's site but can't seem to find all the jumpers he mentions (eg. J488) :-?

Any help from one in the know would be much appreciated!

Cheers :-)

Title: Re: A4000 not working with A3640
Post by: lordnicon on April 06, 2004, 10:39:55 PM

this is something you mine want to know if you did't know.
This card works find in general however it does have a bug related to Zorro II DMA that causes some cards like the GVP Phonepak to stop working, when installed in an A3000. The PAL or GAL chip located at U209 should be -02.
http://www.amiga-hardware.com/a3640.html

Title: Re: A4000 not working with A3640
Post by: Abou27 on April 06, 2004, 10:48:52 PM

I don't have any cards added to it at the moment.  Presumably, this would only affect Zorro II cards added or as it is a DMA problem, can unexpanded systems suffer?

Cheers.

Title: Re: A4000 not working with A3640
Post by: Ilwrath on April 06, 2004, 10:50:41 PM

Quote

I have changed jumper J100 on the MB from INT to EXT and the J100 on the processor card is set to enable MAPROM.

Both J100 and J104 need to be set to EXT.  Also, I'd disable the MAPROM for testing purposes.  (Don't try to enable it until after you get the rest working!)  Also, set the ROMSPEED jumpers to the slowest (highest) settings.  Again, try speeding them up once you get the system able to boot.  But start testing at the slowest settings possible.

Quote

I have looked at Warren Block's site but can't seem to find all the jumpers he mentions (eg. J488)

Not all jumpers are on all versions of the A4000 motherboard, so I wouldn't worry about it.  My 4000D is missing several of the jumpers and connections mentioned.