Amiga hardware info, help and support with a focus (but not limited to) North American NTSC experiences. Open to all.
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RogerWilco486
Boyertown, PA USA

by RogerWilco486 posted Wed Mar 27, 2019 10:03 am

I recently acquired an Amiga 4000 that had it's motherboard recapped by AmigaKit a few years ago. Although it worked, the horrible workmanship of the recap was so severe I just couldn't stomach leaving it be... pads torn off the board, scorch marks, replacement caps soldered so poorly the slightest pressure knocked them right off, and in the cases where the pads were gone, the caps were glued into place with glue oozing through vias into the backside.

I decided to order one of the new replica 4000 motherboards, and my initial plan was to transplant the custom chips onto it and populate the rest of the components with all new parts. But since I had to order the nearly impossible to find DB-23 sockets from Individual Computers anyway, I went ahead and ordered a completely new set of custom chips (minus the CIAs) too.

So now I have a pretty much brand new Amiga 4000 motherboard. I reused the video DAC, CIAs, and RTC chip/crystal, but otherwise everything else is new. Everything works perfectly, and I think it looks really cool too!

IMG_4863.jpg


The old custom chips are now spares-which is nice considering I have several other Amigas that use the same custom chips.

My next project will be to build another A3660, this time in red to match the new 4000 motherboard. :)
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Zippy Zapp
CA, USA

by Zippy Zapp posted Wed Mar 27, 2019 10:26 am

That is super cool, Awesome job! And the fact that it works as advertised after all the SMD work that is awesome.

How many hours did this take you? Did you start with the smallest caps/resistors or any particular order?

Thanks for sharing and that is a great option for battery destroyed boards.

Now I hope someone does a board replacement for the A2000 and a A3000.
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Signman

by Signman posted Wed Mar 27, 2019 3:40 pm

I have to say I am really impressed with your workmanship.
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RogerWilco486
Boyertown, PA USA

by RogerWilco486 posted Thu Mar 28, 2019 6:05 am

Zippy Zapp wrote:How many hours did this take you? Did you start with the smallest caps/resistors or any particular order?


I didn't really keep track but I'd say it was probably about 30 hours or so, perhaps more. Most of the components at the rear of the board near the video/floppy/kb/serial/parallel ports lack component designations--there just isn't enough room. So unfortunately I had to send quite a bit of time using the clunky Pads Viewer for the .pcb file as a map.

As for my workflow, I started on the back side of the board; resistors first, then capacitors. Then moved topside and did the same, plus the MELV diodes. SOT-3 diodes/transistors came next, SIOC ICs, PLCC ICs/sockets, and finally electrolytics--I used aluminum polymer capacitors for their long life and zero change of leaking.

Now I hope someone does a board replacement for the A2000 and a A3000.


Indeed! I've repaired a couple 2000s and one of my 3000s from battery damage...having new blank PCBs for these would have been amazing. Maybe someday someone will donate motherboards to this cause...
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obitus1990
USA

by obitus1990 posted Sat Mar 30, 2019 7:30 pm

Welcome to the club! I finished building one last summer. I am awaiting the A1K 1200/500 remakes and components to arrive, so I can build my own of each of those models, too.
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obitus1990
USA

by obitus1990 posted Sat Mar 30, 2019 7:31 pm

Zippy Zapp wrote:That is super cool, Awesome job! And the fact that it works as advertised after all the SMD work that is awesome.

How many hours did this take you? Did you start with the smallest caps/resistors or any particular order?

Thanks for sharing and that is a great option for battery destroyed boards.

Now I hope someone does a board replacement for the A2000 and a A3000.



The germans at A1K have a 2000 replica in the works, and John Hertell has the A3000 ALMOST done.
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McTrinsic

by McTrinsic posted Sun Mar 31, 2019 12:19 am

Wasn’t there an A3k daughterboard already redesigned on A1K with an icy-port or slt?
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obitus1990
USA

by obitus1990 posted Mon Apr 01, 2019 8:19 pm

Yes, the 3000 daughterboard was done by Matze, with an additional ISA slot or something.
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Mr.Toast
Roseville, CA

by Mr.Toast posted Fri Apr 12, 2019 5:27 pm

Fantastic work on all that! I've been slowly sourcing the logic chips for this build-hopefully you still have some of your supplier receipts to point me to a few odds and ends that I've been scratching my head about. Haven't laid a single bead of solder yet but that is coming soon enough. I have an A3660 that I just had to put down for a bit while I got distracted with a bunch of 8 bit stuff-but I'll be back soon enough!

Mind if I ping you on some items from the BOM in the future (when I loop back to this project)?

That is awesome work-looks sexy and certainly solves the longevity issues. My current A4000 is working but it has so much battery damage (mitigated-but likely hidden surprises lurking) that I would be happier with a complete board replacement-especially all the bodge wires I had to run to get the RAM to work. And I really want the satisfaction that you are experiencing with "I built this!". Congrats on that!
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Zippy Zapp
CA, USA

by Zippy Zapp posted Fri Apr 12, 2019 6:13 pm

obitus1990 wrote:The germans at A1K have a 2000 replica in the works, and John Hertell has the A3000 ALMOST done.

Wow, that is great news. I will buy two of those when they are available. Excellent!

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