A500 ROM Switcher Woes

[Huxley_D]

So in my ongoing "upgrade the A500 beyond any semblance of sanity" project, I've tackled the ROM options. I bought a ROM switcher used on eBay, and (to his credit) the seller was upfront about the fact that the switcher hadn't worked well in his A600, so I rolled the dice and bought it anyway. I've also purchased a brand-new licensed ROM 3.1 chip from AmigaForever. Here's what happens:

* With the original ROM 1.3 chip on the motherboard, everything works as normal
* With the ROM 3.1 chip on the motherboard, I get a jittering purple garbage display for a moment, and then a blank purple display forever
* With the ROM 3.1 chip in the ROM switcher (by itself), I get the classic "Insert Disk" animation but the floppy drive doesn't respond to any inserted disks and I can only get this far if I have the jumper on the switcher enabled (if the jumper is left off, I only get a blank screen)
* With both the ROM chips (1.3 and 3.1) in the ROM switcher, I get a blank screen on power-on, though the LED on the switcher's LED will turn on / off when I hold the CTRL-Amiga-Amiga keys

Other than just assuming the ROM switcher is FUBAR and needs to be replaced, any suggestions on next-steps here? It seems odd to me that the 3.1 chip doesn't work by itself on the motherboard...

Thanks!

Huxley

[Huxley_D]

Revision 5 and earlier A500 boards are wired up incorrectly for 512k roms, so the upgrade roms were sold with a wire between two pins. If you have a Revision 6a and later require you to remove the wire.

I imagine all your problems are related to this somehow.

Oh, interesting! Looking at the ROM chip I bought (here's the URL: http://amigakit.leamancomputing.com/catalog/product_info.php?cPath=40_99&products_id=157 ) made me assume it would be plug-n-play, but now that I'm looking at my A500's motherboard I see that it's a Revision 5 board. The ROM I received from the link above doesn't have any wires jumping any of the pins, but the label does specify that it's for the A500/A600/A2000. Oddly, the chip didn't come with any real installation instructions, other than a folded-up sheet of paper explaining that it needs to be inserted backwards in certain German A2000's. Nothing at all about the A500, shorting pins, etc.

Weird. I suppose your suggestion would account for why it seems to work when its installed in the switcher with the "512k" jumper enabled though... I just wish it would actually boot - it totally ignores any bootable disks I insert (I can hear the floppy drive periodically checking though), even when I've held both mouse buttons down and manually selected the floppy drive as the first boot device.