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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: redrumloa on January 19, 2004, 05:44:25 AM

Title: Weird A2000 problem.
Post by: redrumloa on January 19, 2004, 05:44:25 AM
Quick question. Anyone experienced this problem with an A2000?

The computer turns on, goes through what looks like a normal color cycle on screen, but then fails and reboots. It does this continuously. Every now and then I get a blue color and every now and then i get a green color, but usually it cycles normal but fails and reboots.

I am suspecting a weal or faulty power supply at this point, but it's late and I'm going to sleep:-) Has anyone experienced the same?
Title: Re: Weird A2000 problem.
Post by: zipper on January 19, 2004, 11:32:28 AM
Years ago with A500, with loose chip(s). Bad Agnus contact.
Title: Re: Weird A2000 problem.
Post by: Lemmink on January 19, 2004, 12:41:07 PM
I would point to the Agnus too.
I have an A2000 with a broken Agnus socket here and it shows a similar behaviour.
Title: Re: Weird A2000 problem.
Post by: redrumloa on January 19, 2004, 01:39:29 PM
Just swapped Agnes chips, no luck:-(
Title: Re: Weird A2000 problem.
Post by: Cass on January 19, 2004, 01:57:14 PM
Quote

goes through what looks like a normal color cycle on screen, but then fails and reboots. It does this continuously. Every now and then I get a blue color and every now and then i get a green color, but usually it cycles normal but fails and reboots.


I got similar symptoms when I was trying to softkick (3.1) my A600 (2.05) with chip ram only.

Did you make any hardware modifications/upgrades? Fitting a 3.1 chip on a A2000 might require some modifications (If you're planning to do this, let me know to give you the right instructions).

This is a hw case but you might give a look to the ROM sockets and check the ram chips.

I hope this to be of some help...
________
Full Melt Hash (http://trichomes.org/hashish/full-melt-hash)
Title: Re: Weird A2000 problem.
Post by: redrumloa on January 19, 2004, 02:38:29 PM
Quote
Did you make any hardware modifications/upgrades? Fitting a 3.1 chip on a A2000 might require some modifications


Nope, affraid not. This is a unit that had a toaster and KS1.3 ROM, but has been sitting in storage for many years. The only modification I did was to replace the battery, even though it looked fine when I got the box.

Quote
I hope this to be of some help...


Yup, sure is. I don't work on these every day so any suggestions are good, thanks:-)
Title: Re: Weird A2000 problem.
Post by: zipper on January 19, 2004, 03:28:39 PM
Have a precise look at your Agnus socket. There was a bunch of 500s with crappy ones, prone to cracking (yes, I have a cable tie round the socket...) - perhaps yours is a good one but maybe oxidised.
Title: Re: Weird A2000 problem.
Post by: mikeymike on January 19, 2004, 03:29:58 PM
Does the power light flicker oddly?  I had similiar behaviour happen on an A500 with an aging PSU.
Title: Re: Weird A2000 problem.
Post by: Markus_Bieler on January 20, 2004, 08:40:05 PM
Quote
The only modification I did was to replace the battery, even though it looked fine when I got the box.


 - Swap the CIA chips.
 - Change the denise-chip
 - Disconnect the keyboard

- Could be bad 1488 or 1489 (little chips near the serial port, sadly soldered directly on the board.