add 1 MB onboard ram to A500 Revision 6A MB

[klx300r]

Tenacious wrote:
@ klx300r

You sucked the solder out of the MB?

Certainly, solder the chips back in.  Try to alternate between chips to prevent overheating any one of them.

Good Luck!

ya i initially was gonna solder 4 new 256 drams into the empty sockets on the 6a mb but now i'm gonna go on the safe route and just leave my 512 trap door expansion in and allocate that to chip ram so that i get a 1mb chip ram total an hopefully keep my RTC working...my supram500rx and a590 will take care of the fast ram.

saying that I understand I have to open jumper 7A and do something else to jumper 2..(can anyone confirm what I must do to jumper 2 please...i checked aminet with no concrete answers there...thanks for the help :pint:

[klx300r]

EXCELLENT :-D  Just finished the mod and it worked great !!! got a bit of a scare when I first booted it up & got greeted by a green screen but I troubleshooted the problem as being some extra flux on the board sooo after a good cleaning all was fine and peace was restored back in my Amiga land :lol:

thanks very much for your help :pint:

[klx300r]

eslapion wrote:
Woaaa... what is this thread exactly about?

Did you want MORE than 1MB chipRAM or did you simply want to add 512k onboard and go from a 512k total ram Amiga 500 to one with 1MB chip?

I have an Amiga 500 here with 512k and the same MoBo revision. I also have piles of 256kx4 DRAM chips that are exactly the same type and I was asking myself exactly what I should do to expand the 500 to 1MB and make sure its all chip ram.

BTW, the Agnus chip in there is 8372A which does support 1MB chip.

eslapion! dude yur everywhere man :-D  anyhow to make a very long story short YES you are able to get 1 mb chip ram with a 8372A agnus by basically cutting 2 jumpers and soldering 1 i.e see JP7a and JP2 & see link above...this mod allocates the trapdoor 512 k to chip memory rather than fast...