Amiga 1200 and RAM expansion problems

Hello, I've been a member for a while, but I haven't posted anything in the forums other than interest in buying things :P.
So I'm presented with a problem now and since there a handful of people here are Amiga nuts(in a good way :D) I thought I'd share it with ya.

So I own a german Amiga 1200 with board revision 1D4 and Kickstart 3.0. The classic :D. Now the thing is, this Amiga works fine as it is. But I hate floppies and the reason I had got an A1200 was to install WHDLoad and never look back! So I had a friend give me an imagefile of his HD which has tons of WHDLoad games and I loaded it on an SD card, then put the card on an IDE to SD adapter and then straight to the Amiga. It worked fine, but of course you can't go far with 2MBs of RAM ;). Some games worked, like Turrican 2. Agony produced this weird kind of thing where the sound came out garbled and f****d up, at the very first scene, with the whole high resolution gray background thingy. After that it just crashed. It did work fine on WinUAE, but I wasn't really worried.

So I got a RAM expansion after a while, with the memory being onchip. I put it and it produced all kinds of weird problems. It would corrupt the disk and make Workbench crazy about checksum errors, games would get stuck at the start or not load at all giving me a memory address problem and others even went as far as to make the Amiga go off sync:wooha:.
Games that worked fine before didn't work with the extra RAM. It was recognised correctly on the Workbench though.

The obvious culprit is the memory. So I had a friend lend me one of his own. It produced the same errors! He also gave me a diagnostic tool on a floppy with some memory test, but it passed the test successfully 20 times! Somewhere around then, I found out another weird problem when the RAM board was installed. Some floppies would get stuck when being accessed! For example, Benefactor would hang when loading the first level. The floppy just stopped accessing the disk, but you could hear the drive spinning! So I was under the impression, that maybe the PSU had died. I tried with another one and although that problem disappeared, the rest persisted.

I finally gave up. I'm pretty sure it is the motherboard now, but if there are any solutions to this or if anybody has another idea I'd like to hear it. :lol:

The usual suspects: bad capacitors and weak power brick. Mostly the the second.

Swap the brick for another one or hack an ATX PSU from pc world and all your Amiga worries will be vanished away.

Quote:

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Originally Posted by rkauer

The usual suspects: bad capacitors and weak power brick. Mostly the the second.

Swap the brick for another one or hack an ATX PSU from pc world and all your Amiga worries will be vanished away.

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What is the power brick you're referring to? The PSU?
Like I said I tried two of them, so it doesn't make much sense.

They could easily both be dud power bricks. They are not very good pieces of hardware, probably Commodore's worst oversight.

Can you try cleaning the connector?

But one of them was tested and working on an expanded Amiga.
I'm going to try with a third, but it just sounds plain weird to me. The capacitors seemed fine, but I might have a closer look at them.

EDIT:

Hey Hell_Labs, I forgot to mention that I cleaned the connector to the best of my capability. Still didn't work :(

Screams bad memory to me but the chances on both the cards are slim.
If you've cleaned the edge connector my next look would be the power supply and then motherboard caps although i think this is unlikely as the amiga runs ok unexpanded.

Some RAM expansions require the memory to be set a SINGLE or DOUBLE sided banks - this referes to the SIMM installed - single sided or double sided.

If you have a double sided SIMM (most 8MB units are) and the card is configured as a single bank then you will get error's crashes and a lot of graphical glitches when you reach 50% of memory installed.

If you are unsure on what Adapter you have post a pic - there's some serious hardware guru's on here =D

Hey, like I said the RAM is surface mounted on the controller itself so it's not removable. For reference, it's the Power Computing: PC1204 card.

Thank you all for your replies btw, it's nice to see so many people eager to help me :)

Yeah zip rams on them.

What was the other memory expansion you tried?