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Author Topic: A500 doesn't work with RAM expansion... HELP  (Read 1832 times)

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Offline zonaps2Topic starter

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A500 doesn't work with RAM expansion... HELP
« on: August 05, 2007, 05:14:52 AM »
Hi,
I have an Amiga 500 and a 1084s commodore monitor since 1990,
It was stored for a long time 'til a week ago.
I plug in all and still works!, but I have to remove the trapdoor 512k RAM expansion.

Screen turns yellow at the booting sequence when RAM expansion is on the Amiga.

RAM model is MicroBotics M 501, I took the battery off 'cause it seems dead and cleaned the board, looks preety ok to me, no corrosion.

The Amiga works fine without the expansion but half of my games are useless now.

Can I do something to repair it?
Or is a problem on the Amiga motherboard?

(Pictures were taken with a cellphone and a scanner, sorry! ) :roll:



 

Offline Zac67

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Re: A500 doesn't work with RAM expansion... HELP
« Reply #1 on: August 05, 2007, 09:34:23 AM »
A 512K trapdoor expansion is hardly worth repairing; it's probably much easier to get another one.
Otherwise it's seems cleaning up battery mess isn't enough. You'd have to fix any damaged traces. A yellow screen does indicate a RAM problem (an exception takes place before the OS setup has progressed far enough to e.g. display a Guru) - I assume, you've got a 512 K chip and 512 K 'fast' config, so the OS data is put into expansion RAM - which isn't working correctly and crashes the machine.
 

Offline amigean

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Re: A500 doesn't work with RAM expansion... HELP
« Reply #2 on: August 05, 2007, 11:58:38 AM »
The underbelly of the ram expansion board does look pretty damaged to me, right underneath the place the battery sits - looks like acid damage too.

Given the dangerous nature of these chemicals, and the price of a A500 ram expansion, you'd be well advised to steer clear from repairing it and just get yourself a new expansion off ebay for a tenner...

 

Offline zonaps2Topic starter

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Re: A500 doesn't work with RAM expansion... HELP
« Reply #3 on: August 05, 2007, 06:21:36 PM »
Ok, thanks for responses, I'll get a new one from ebay, since I'm in Uruguay shipping cost always rises the price of the items.

Another problem:
I've noticed that one of the sound channels isn't working on the monitor, I'll try to disassemble later.:-?

Thanks
 

Offline Braddo

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Re: A500 doesn't work with RAM expansion... HELP
« Reply #4 on: August 05, 2007, 06:31:53 PM »
Looks pretty ok? No corrosion??

You've got to be joking!
 

Offline zonaps2Topic starter

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Re: A500 doesn't work with RAM expansion... HELP
« Reply #5 on: August 05, 2007, 07:13:49 PM »
I don't know much about electronic components and it seems to me that just the green layer is peel off.
But looking at it now you're right, looks pretty damaged.
My mistake!