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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: EugeneNine on August 25, 2016, 04:03:55 AM

Title: A2000 battery damage green screen
Post by: EugeneNine on August 25, 2016, 04:03:55 AM

Hello all,

I picked up an 2000 a couple weeks ago after not having an Amiga for many years.  I found it did have battery damage so I removed the battery first

I then found the 68000 had one pin not in the socket making me think someone was swapping parts possibly trying to fix it or another.  I pulled the 68000 out and could see one pin of the socket was in bad shape so I have removed the socket.

Here you can see some of the damage (phone blurred a bit)
(http://i306.photobucket.com/albums/nn275/eugenenine/Misc/KIMG0456.jpg) (http://s306.photobucket.com/user/eugenenine/media/Misc/KIMG0456.jpg.html)
Since the socket was bad anyway I did a destructive removal.  Ripping the plastic off makes it easier to desolder one pin at a time rather than having to get all 68 loose at the same time.

I resoldered in a new socket but still get a green screen at power on.  Looking for some more troubleshooting info.

Title: Re: A2000 battery damage green screen
Post by: Acill on August 25, 2016, 04:56:56 AM

Typically a green screen is a chip ram issue. Check all traces for breaks. If you have a microscope it helps a lot.

Title: Re: A2000 battery damage green screen
Post by: hese7 on August 25, 2016, 06:59:22 AM

Quote from: EugeneNine;812936

Looking for some more troubleshooting info.

Already given:
http://eab.abime.net/showpost.php?p=1107581&postcount=16

Title: Re: A2000 battery damage green screen
Post by: EugeneNine on August 26, 2016, 05:33:18 PM

I suppose the Amiga world is quite a small world :)  
I did see the suggestions in the other board.  Typically I might hit two or more boards of interest expecting to have different audiences and therefore different experiences or other suggestions.  in this case it appears to be the same audience :)

I did manage to find a scan of a schematic but its pretty small, wish I had kept my Sams photofacts copies I made in college.

Title: Re: A2000 battery damage green screen
Post by: orange on August 29, 2016, 02:11:40 PM

perhaps this photo I made : http://www.amiga.org/gallery/index.php?n=2390
could be of some help.

Title: Re: A2000 battery damage green screen
Post by: EugeneNine on October 07, 2017, 07:57:47 PM

Well, I finally got a few minutes to look at it.  Found no continuity between D1 and D2 and the U105 and U106 buffers.  It seems the traces erode right at the vias.  So i jumpered across those but still a green screen.  My guess then is a couple more of the vias closer to the battery, I need to trace those out.

Also the schematics I found online have different ram chips than my board.

Title: Re: A2000 battery damage green screen
Post by: Acill on October 07, 2017, 08:49:29 PM

Quote from: EugeneNine;831431

Well, I finally got a few minutes to look at it.  Found no continuity between D1 and D2 and the U105 and U106 buffers.  It seems the traces erode right at the vias.  So i jumpered across those but still a green screen.  My guess then is a couple more of the vias closer to the battery, I need to trace those out.

Also the schematics I found online have different ram chips than my board.

Dont forget to do jumps on back of board too when you have a broken VIA. Thats what they are after all.

Title: Re: A2000 battery damage green screen
Post by: EugeneNine on October 07, 2017, 10:11:38 PM

The traces seemed to have broken right next to the via.  I have continuity between the 68k and the buffers now on all the data lines, the trace on the back tests ok.

I tested between the 68k socket and the via on the left of the wire and had connection.  Then from the via on the right side of the wire to the buffers had connection so from the via to via where the wire is there was no connection until I soldered the wire.