I scored a heavily modded A500 ... but....

[IvanEBC]

Hi Guys.

Scored two Amiga 500 last weekend.

One stock standard visually, found it had kickstart 1.2 so the 40 original games i scored with it, only 9 worked. Figuring ks1.2 may be part of the problem i went to look at the 2nd Amiga 500 and found quite a few interesting bits internally.

First.... there was ... this chip. He did mention about a 68010 that was a bit perfect upgrade (no idea what that means) so it has been mounted on top of a 68000 and its connected to a switch so you can switch between them (not live probably).
http://www.users.on.net/~ivanw/IMG_3251.JPG

The other is a Multivision500 which sits on a raised socket and Denise now lives in a high rise apartment. I wanted to remove this sucker for testing but Denise is all soldered into place. So i left it there.
http://www.users.on.net/~ivanw/IMG_3250.JPG

The internal floppy was recabled to be external and sit in an external casing holding original DF0 with an external floppy. It was quite the setup.

Anyways. it is kickstart 1.3, for all intents and purposes, the Amiga looks like it boots and works. But no disc (even a working one i tested only an hour before) just won't boot. I get a double "seek" noise as it looks at the floppy, then fails nothing.

I tried the motorola switch in both positions, and i even removed disassembled the external floppy housing and tried both floppy drives connected directly back to the motherboard, and both floppys react the same way - two clicks, doesn't boot. 1.3 Kickstart hand stays there.

Maybe there's something i'm missing here in terms of a chip that controls floppy reading that needs a clean (this AMiga is pretty dirty and scrubbing the top case hasn't done a great deal of help)? or maybe i really am just lucky to find two bad floppies and i have to disassemble the working ks1.2 machine just to test that out?

I'm in need of a bigger desk.

Thanks

Ivan

[KronusOfChaos]

Try swapping the 2 CIA chips in it and see if the floppy starts working. One of the CIA's could be bad. and By swapping you might see something else have issues, but your floppy works. Or ou could swap the cia's from the other 500 and see if it works with those. If it does work then one of the two cia's are bad.

[IvanEBC]

yeah cool, i hope the other is socketed cause i'm only a novice solderer.

I actually have a gotek i can use thats not connected so i might quickly try that as well.

Thanks for your time.

[KronusOfChaos]

Yes the CIA's are socketed they are the 2 that are labeled 8520. You might already know that if so sorry for repeating...lol...So very easy to remove. And if you have a gotek then that makes testing a bit easier since you can connect to the motherboard's fdd connection.

If you need more help pop me an IM.

[André]

Not sure if this is related to the issue that you're seeing but the stacked chip in the first image (with the switch attached) is a CIA [labelled CSG 8520] not the 68000 [or 68010].

[Jope]

The stacked chip looks like a boot selector. The internal floppy boots in one switch position and the external floppy boots in the other position.

Could be a CIA issue, could be a Paula issue..

The second board is an internal flickerfixer/scandoubler.

[hooverphonique]

yes, the first photo looks like a boot selector, as Jobe said.

are you sure Denise is soldered? hard to see in the photo, but it looks like it's "just" heavily oxidized..

[happymondays]

It is definitely a boot selector, I have a similar one. The internal floppy drive might have died and the boot selector may serve the purpose of having the external set to DF0.

[ChrisUnionNJ]

From my look of the pic the Denise is in a socket..

[IvanEBC]

ok.

Boot selector switch - Perfect you are right. The internal floppy was moved to the an outside casing that actually held TWO drives (one being the internal). So half my issues might have been it was looking for the wrong drive. Oh thats a can of worms, if i connected a single drive back to the internal port only, what's that switch going to do, would it interfere with "normal" internal DF0 setup and requires two drives connected externally to work correctly? Hmmmm

Again, correct, Denise is socketed, so i can likely remove that and place that back into the original position, i don't really want that extra board. Someone stacks i think 2 x empty socks on top of each other to give it height, so should be easy enough to undo.

Cause i was having issues though - i took the 1.3 kick rom from the modded Amiga and moved it into the 1.2 kick Amiga and found half my non working games, worked again. So having a spare 1.2 kick rom, i placed it into this modded amiga but she gurus when turning on .. bugger, made it WORSE lol, but at least i have one good Amiga.

Maybe if i put denise back, it'll help cause maybe the multivision needs 1.3.

But i think the floopy thing is still going to cause me issues with the mod thats done, i just can't place the internal back inside and have it work like a regular Amiga.

Ivan

[IvanEBC]

I think i'm giving up on this for now.

I put Denise back into her original socket, and for simplicity sake, connected the Gotek to the floppy cable - and it bootup up, informing me no virus on bootblock, so i know it works, forgot to connect a mouse, so turned it off, without actually connecting the mouse, i turned it back on again and that was it... nothing... Just a flashing red power light. I didn't unplug or even touch anything - i might have tried moving the gotek for to 000 (selector.adf)

I then thought - i'll do the same with the CIA, removed the top chip and placed it back into original position so not more selector, i didn't need that feature as i have several other floppies i could use, or even the gotek. Still nothing, just Gurus. Removed the gotek, and it booted to the 1.2 rom hand, but turn it off and back again, and no rom hand... grr, it just picks and chooses what works and when.

I might put it aside for spare parts.

Ivan