Amiga 500 rev5 - Kickstart 3.1 upgrade issues

Hi, I'm trying to upgrade my Amiga 500 revision 5 board to Kickstart 3.1. I have the chip, and have attempted to do the modification for 512k ROMs (pin 1 -> 31, pin 31 -> 21) and the system just shows a blank screen when powered on (no keyboard lights either). System is fine as it boots normally when my 1.3 ROM is put back in.

I've had trouble finding well explained, illustrated info on this process, so I suspect I have made an error somewhere. I've also found contradictory information: some sources say to literally connect pin 1, 31, and 21 all together (which wouldn't make sense as it would ground them all wouldn't it? I think is incorrect) -- others say to solder to pin 1, insert the other wire in pin 31 on the socket, and then solder a wire between pin 21 and the original, now lifted up pin 31. I think that's the correct way but I can't figure out if it's possible to do cleanly without soldering to the actual board instead of just the chip. Regardless, I actually tried both of these and the system doesn't do anything.

Can someone illuminate me on all this? I have to be doing something wrong here...

[Viserion]

I used A500 rev5 Kick3.1 Upgrade

Get a socket to do the soldering on. It's easier, and is easier to reverse should you want to in the future.

As you can see in the link I provided you should bend pin 31 up so it has no contact with the socket.

Then solder the pins.


I needed the 3.1 rom for an another Amiga, so I removed the 3.1 rom and inserted a 1.3 rom instead(mine had originally a 1.2 rom).

I still have the socket I modified so I could change again.

Tried to find it so I could take a better/bigger picture for you, but don't remember where I put it.

Anyway, I succeeded using the link above

[Jope]

The wording on that page is a bit difficult to follow, but it is the correct procedure. It's worth taking a look at the picture of the socket near the top of the page, it'll be clear then what goes where.

It's definitely a good idea to have the intermediate socket in there if you can fit one vertically.

Thanks. Good to see a definitive link. Turns out it was exactly what I was doing in the end, but my soldering at some point didn't turn out right. I was pretty much stuck soldering directly because I don't think I have enough vertical real estate to add an intermediate socket, as I have a kipper2k RAM/CF expansion immediately above it (why I needed Kick3.1 in the first place!) Regardless, redid it and now the system is up and running!

Side question: In the future once I get a 1MB Agnus I may look at modding it for 1MB chip RAM using the trapdoor RAM. I have a 512k trapdoor RAM card in there now, but it's not an A501 (instead one that I -think- is called a PPS EXP 512 but I'm having trouble being certain). Would such a modification still work or do I need a genuine A501 to use trapdoor as chip?

[Jope]

It makes absolutely no difference what brand of trapdoor expansion you have. :-) If it works fine as $C00000 RAM, it will work fine as chip RAM.

2016 edit: some older slower trapdoor cards have been shown to be unstable as chip RAM! The newer four chip models should all work fine.

[dirkies]

Hello lads
I bought a kick 3.1 rom from AmigaKit for my A500 (40,63 for A500/600/2000), but I can't get it to work. Maybe I am doing something wrong, but I think I did all the correct things.

A) this is a REV 5 A500 so need to do some mods first
B) connected pin 1 with pin 31 on mainboard
C) connected pin 21 with pin 31 on the kickstart chip
D) pin 31 of kickstart chip bent upwards so it does not connect with mainboard

all that happens is a yellow screen and red power led blinking as with a guru (although no guru appears, just yellow screen >cpu error?)

putting original kick 1.3 chip back in will make A500 power up without any issue.

Could it be this 3.9 chip is not ok? How can I test that? And since I need to do the mod, will Amigakit replace it if it is broken? Not gonna buy another one just for testing sake...

Any suggestions welcome!

[dirkies]

here is my modified chip. No dice. And I have a kipper2k 508 too, cannot put socket inbetween.

https://drive.google.com/file/d/0BwT...Ylk/view?pli=1

Pin 31 is bent up. I used a slide-on connector instead of soldering on pin 31 just to be able to take it off easily in case I would put chip in later revision A500.

So what do I wrong?

[Jope]

It definitely looks right.

To test: stick it in a rev6 or an A600? I take it you don't have an EPROM reader to read it with?

[dirkies]

No. Only have an a4000 besides my a500. I will contact Amigakit and hopefully they'll send me a new one.

[dirkies]

Now it gets weird. Amigakit got the chip back and they say it works

I did the same wire mod on a spare 2.05 ROM and that works just fine on the same A500.

Any ideas why the 3.1 ROM remains stuck on a yellow screen while a 2.05 ROM works fine? Is there any known issues with a 3.1 ROM on an old full OCS A500? (no addons installed btw, it is a "naked" A500)

[Solo761]

What kind of chips Amigakit uses for these kicstarts? OTP ROMs or EPROMs? Could it be chip's speed is the issue? I think people recommend at least 120ns chips for A500, some people had success with 150ns ones, but some didn't. And when tried in A2000 same chips, that didn't work in A500, worked fine.

Although I don't remember how this error manifested itself, yellow screen, guru errors or some other screen color.

[dirkies]

they came back to me saying they use AMD 150ns chips, adding that I am the first customer where they do not seem to work. The chip that was sent back works on their A500s, but they do not have rev5 machines to test it seems.
Question is now what the next step will be...

[dirkies]

ok, so I will get a refund for my KS ROM, now the question is where can I get a working 3.1 ROM for my Rev5 A500, as they seem to be out of stock everywhere.
Maybe a chip I could flash, but would be silly to buy all the eprom flash equipment for just a single use!

[Jope]

This makes me want to try to burn a 3.1 ROM and install it in a Rev 5. :-D I happened to order some new EPROMs lately, so maybe I'll give it a try.

[kipper2k]

i have a few rev 5's, i'll try a few different chips to see what happens here

[Zippy Zapp]

I remember back when I was sent a 2.04 ROM by Commodore, if I recall it had jumper wires already installed for older revisions of the 500. Mine happened to be a Rev 6 so I had to cut the wire. But my friends was a Rev 5 and he had to leave it be.

Seems odd that a 2.05 will work but not the 3.1 with the same mod.

On a side not what type of EPROMS do you buy to test these things out and where do you buy them? Does Digi-key carry these? I am purchasing a USB programmer and was told that with an adapter it can work for Amiga ROMS. I bought it for programming C64 ROMS.
Would be nice to make patched ROMS and for testing...

[Jope]

Digikey probably doesn't have them, the 27c400 hasn't been manufactured for quite some time.

Damn it, I forgot to try the 3.1 ROM in a Rev 5. Perhaps this weekend.

[Zippy Zapp]

Bummer. So are they getting hard to come by? Or is there replacements?

[Jope]

HK chip brokers always have them on eBay. Shipping times are quite reasonable too.

[kipper2k]

I just done some testing on my Rev 5 A500 with the modded KS3.1 chip.

So with the modded (27C400) KS3.1 chip same as the picture of the Amigakit KS the computer gave me a Green screen.

I took out the already installed 8371 Agnus and replaced it witha 8372A Agnus and up comes the nice purple splash screen.

What Agnus do you have in the computer you are trying to get working ?