Varta strikes again! (Amiga 2000 Help)

[cbmeeks]

So I decided to start restoring my Amiga 2000. I knew that a Varta battery had leaked years ago (I removed it long ago) but the damage was already done.


Not until today have I seen the true damage. I removed the CPU, ROM and a few of the resistor packs.


Before I did that, all I got was a black screen.


Anyways, I believe the alkaline has been neutralized so now I'm in clean and repair mode.


When looking at pic below, you will notice the left pin of the CPU that is circled makes a solid connection to the bottom pin of RP900. But then that same pin appears to go to the via over to the right. But it doesn't.


I scraped some solder mask off and if you look real close, the pad in the middle (bottom of RP900) appears to be connected to the copper to the right. But it isn't that I can tell. However, that bit of copper DOES make continuity to the via to the right.


My eyes tell me that all three of those should be connected. The pin of the CPU, the bottom pin of RP900 and the via on the right.



I have the schematics for the Amiga 2000 REV6 but my board is a REV4.1.


So, do you think I am correct? If so, I can fix the trace.


However, without the true schematics, I'd hate to make a mistake.

Thanks!

[Vypr]

The Service manual you can download here: http://www.retro-commodore.eu/downlo..._Main_Unit.pdf has the schematics for the Rev4 A2000.

If I'm reading the schematic properly, The pin on the CPU you have circled is Pin 64 of the CPU which is D5. It should connect to the pullup resistor pack at pin 10 of RP900 (the pin you have circled) and then feed off to Pin 6 of U603.

I would first check that is correct by checking continuity of the via to that pin, if it is a jumper wire can be put on pin 10 of the RP00 and the via.

[cbmeeks]

Getting a "file not found" on that URL. Perhaps a typo or maybe an old server?

Thanks!

[jasonsbeer]

Originally Posted by cbmeeks

My eyes tell me that all three of those should be connected. The pin of the CPU, the bottom pin of RP900 and the via on the right.

Your eyes do not deceive you. You should have continuity as you describe. I've been working on a rev 4.4 board and I think I've gone through everything so many times, I have the schematics memorized. In fact, I was looking at that trace just last night.

Here is a link for the service manual with rev 4.x schematics.

http://www.retro-commodore.eu/downlo..._Main_Unit.pdf

[Argo]

This Jan Beta video may be of some help

[ Show youtube player ]

[cbmeeks]

Originally Posted by Argo

This Jan Beta video may be of some help

[ Show youtube player ]

That video is what inspired me to finally get the A2000 off my shelf and start repairing it. GadgetUK also did a great series recently on the A2000.

Originally Posted by jasonsbeer

Your eyes do not deceive you. You should have continuity as you describe. I've been working on a rev 4.4 board and I think I've gone through everything so many times, I have the schematics memorized. In fact, I was looking at that trace just last night.

Here is a link for the service manual with rev 4.x schematics.

http://www.retro-commodore.eu/downlo..._Main_Unit.pdf

Thanks, I knew I wasn't crazy. I will fix that break today, hopefully. That is, after all of these work deploys I have to do...ugh.


OK, I'm still getting a "File not found" error when I click that link. Anyone else have that error? Could someone please post it as an attachment or maybe know another download?

[Vypr]

Try thisd link, you should find a working link on this page
http://www.retro-commodore.eu/amiga-...=506&width=700

You're looking for the Amiga 2000 Service Manual Main Unit document

[cbmeeks]

Thanks, that link worked.