A500 Rev5 1Mb Chip Ram Mod
 

Could someone point m towards a tutorial to modify my Rev5 A500 to 1Mb Chip Ram please?

I have dropped in a 8752A Agnus and already have a 512k trap door expansion in place.

(Google'in at the mo but keep fend Rev6a).

Thanks in advance.

At least Megachip manual has the instructions in it:
http://amiga-manuals.xiik.net/manual...Manual_ENG.rar

Perfect thank you very much.

Worked a treat. 1Mb Chip Ram!

Nice! (did it to my rev6a, then Megachipped to 2 MB).

Sweet! *pics please* ;) =)

It's buried under the KS swither in my a500T, sorry...:nutshttp://www.amiga.org/gallery/images/62/1_3018.jpg

Just to have the relevant info in this thread..

JP2 goes like in the Rev6 and for JP7, just flip the switch in your 3rd party ram expansion to disable it. If your ram expansion has no switch, then you must find the _EXRAM trace that goes from the trapdoor slot to GARY's pin 32 and cut it. Alternately you can just lift out GARY and bend out pin32 so that it no longer makes contact with the socket to isolate the signal. (no, don't bend out GARY's pin)

With my 8752A Agnus in place am I stuck in NTSCv bit hard to tell with my scart connection and plasma screen (42" Kickstart 1.3 boot screen!)

That can be alleviated by gluing a thin sliver of sticky tape on the pal/ntsc select pin before plugging the new agnus into the Rev5 A500.

Sorry for posting to an old thread, but some relevant info regarding chip RAM mods. It's also possible to add 1 MB chip RAM with no motherboard modifications whatsoever, if you are afraid you'll ruin your Amiga or have rev 3 motherboard where this mod is more difficult. Check out https://inkoovintagecomputing.wordpr...modifications/

This does require electronics skills though, but may be worth for some users. Also, it's possible to switch between chip/slow RAM and PAL/NTSC with some jumpers after this.

That is a very interesting approach. A middle ground between a regular RAM expansion and the MegAChip. If only the PLCC connectors were not so expensive :)

I tried to found how to make 1mb chip ram mod to rev 5. motherboard, but all pictures seems to disappeared.

I'm little confused, when / what situation I need to cut JP7A?

Also, I have problems to make these mods work with KS1.3 but not with 3.1. Is this normal, should Agnus 8372 just work with lower kickstarts?

MegAChip manual has the instructions: http://amiga.resource.cx/manual/MegAChip.pdf