Amiga defect!?

[ZyBeR]

Please tell me what hardware I need to do this!

[spirantho]

I imagine any old EPROM and EPROM burner should do the trick. A simple 8K EPROM like a 2764 would work, but you may need to wire it up slightly oddly as the Amiga is expecting a 256KB or 512KB ROM, not an 8K one. I'm not sure what the pin-outs on the Amiga ROM chips are - they might be the same in which case you shouldn't need to rewire too much.

I wouldn't recommend it unless you at least understand basic logic circuits and about chip select lines and stuff... but then you're unlikely to own an EPROM burner if you don't.

Maybe someone else has actually done this...? I'm only working from a theory (though I think a good one).

[orange]

great idea, though there is some sort of check already builtin ROM, those coloured screens like green - chip ram etc..

[ZyBeR]

My problem is solved!

A friend of mine had a look at it last weekend and found out that the soldering on the pins on the 060 socket had some cracks. After re-soldering them the machine now works flawless! I have had in one for 48h without a crash (heavily modified wb + miami dx + amirc)

[Piru]

The first thing I would do is burn a simple ROM with something like (pardon my asm, it's been a while):

START MOVE.L #$0000,D0
LOOP MOVE.L ($DFF180),D0
INC.L D0
JMP LOOP

Now from memory, and it's been a long time so I've probably got the syntax/numbers wrong, but this would just increment the background colour, resulting in multicoloured strips all over the screen - if the system is working.

Too bad this is not enough. When the Amiga system is powered up the colour burst DMA is turned off, thus you won't see anything at all. So to see anything at all, the colour burst DMA must be explicitly turned on first.

Fixed code:

Code: [Select]


start: lea    $dff000,a6
       move.w #$7FFF,$9A(a6)  ; All ints off!
       move.w #$01FF,$96(a6)  ; All DMA off!
       move.w #$0200,$100(a6) ; Colour burst on!

       moveq  #0,d0
loop:  move.w d0,$180(a6)
       addq.w #1,d0
       bra.s  loop


Further, at this point the ROM appears in place of the chip memory until the ROM overlay bit is turned of from CIA... So in case you must check chip ram, you need to turn off the overlay first.

[Framiga]

@ZyBeR

whot! this is "weird" seen that you have tryed another 2 CPU board!!!

Have you checked to have the right standoff for your CPU card?

A4000T were bundled with too long standoff . . .no problem with a 3640
but with a CS or CSPPC, this could be a big problem.

There are some useful pictures here in the Gallery.

Thanks to X-ray :-)

http://www.amiga.org/gallery/index.php?n=873