Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: jedcooper on September 08, 2012, 09:03:06 PM

Title: 2MB RAM for Amiga 500 Repair help
Post by: jedcooper on September 08, 2012, 09:03:06 PM
Hello!

Got a Roßmöller 2MB expansion in a A500.
http://amiga.resource.cx/exp/search.pl?product=&company=ro%DFm%F6ller#a2mb500 - A2MB-500
Unfortunately some cables aren't soldered on their position anymore.
The manual says how to solder them, but only for normal Agnus chips. I have a 8375.
What now?

!!BTW!!: Are there known issues DF1 external drives not working anymore with 2MB RAM adaptor or is it only because of wrong jumper setting/missing cables?

The RAM works, but no external drives.
Title: Re: 2MB RAM for Amiga 500 Repair help
Post by: Zac67 on September 08, 2012, 10:16:06 PM
Unless you've got an A500+ (2 MB Agnus) the pinout is always the same.
Most 2 MB slow RAM expansions only work with the initial 512 KB chip/512 KB slow mem config, but this one seems to be fine with 1 MB chip when jumpered appropriately.

The problem with the external drive is pretty strange. The internal is working AOK at the same time? This should only be happening if you connect any of the jumper cables to the wrong pins...
Title: Re: 2MB RAM for Amiga 500 Repair help
Post by: jedcooper on September 08, 2012, 10:22:17 PM
Drive DF0 internal alone working fine.
it was something like accessing DF1 then BOTH drives were accessed at the same time on same tracks I guess. weird

for the RAM issue: so i follow the manual for the big fat agnus mentioned 8372 (which is compatible to built-in 8375)?#

Cause disk access iirc has to do with the gary, and this RAM expansion uses the gary I thought the issue might come from not yet connected/soldered cables maybe?