Megachip 500/2000 problem

Hello all,

I'm making a little monster A500 with very cool stuff include some hardware I made my own.
I also own a megachip A500/2000 solution with agnus 8375 that I would like to add this little stuff for more chip ram.The problem is that my miggy refuses to boot with this board attached,even with stand alone 8375.It only works great with 8372A.I have soldered the required pin on Gary chip,but like I said.....nothing on screen.I read from "big book" about this stuff.I says that IF amiga will not corporate with the solder solution on gary chip,I have to attach the cable to the 68k cpu.The pin number is unknown.I think that might be the same signal gary share with the cpu....
Ah!The amiga 500 rev is 6A.
Has anyone this board attached to 68k??

Thanks for your time,
Giorgos

[alexh]

RTFM

http://amiga.resource.cx/manual/MegAChip.pdf

I take it that you did not have 1Mbyte Chip RAM and needed to do steps 8 & 9?

If not then perhaps it is broken? Or NTSC? What is the number written on the top of the chip?

[DoogUK]

Originally Posted by alexh

RTFM

http://amiga.resource.cx/manual/MegAChip.pdf

I didn't notice the manual.
I have 1mb chip ram of course,this was the first thing I did for upgrating A500

It's not ntsc.Like I said,my miggy doesn't work,even with only 8375.I have 3 of these chips(PAL) and I tested all of them stand alone without any result.On an other one 6A stock mobo it doesn't work too.It might be the mobo rev because on 8A(like A500+) works fine,mounted on gary.That's why I wanted to know the 68k attach pin for megachip.But the mobo has a lot of mods and I don't want to start from the bigging
I'll test it tomorow

Thanks

[alexh]

Originally Posted by pontium

Like I said,my miggy doesn't work,even with only 8375.

It's not supposed to. Not unless it is a 1Mbyte 8375.

Originally Posted by pontium

I have 3 of these chips(PAL) and I tested all of them stand alone without any result.

What versions? Any 318069-10 ones? Want to sell one

Originally Posted by pontium

On an other one 6A stock mobo it doesn't work too.

No A500 (non plus) motherboard can use a 2Mbyte 8375 Agnus without a MegaChip (or similar).

Originally Posted by pontium

It might be the mobo rev because on 8A(like A500+) works fine

Cos it is designed to take a 2MByte 8375 Agnus.

It works!!
I soldered the megachip cable to 86k.It's very strange that worked with this.I'm a litlle bit confused.
About the other A500 rev 6A you are right.It is a stock mobo like I said,so whats the reason to corporate with this.Ah....my head

I forgot to write the revisions of agnus,but I remember a "11" parameter on one of them,or I was looking a superbuster-11 chip,because I changed one on an A4000D today.

Anyway,thanks again man for the manual and your advice!