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Boards

Board beyond saving: transplant to a new board

When corrosion from a battery or capacitors has eaten traces and vias all over the board, there is an alternative to throwing the machine away: build a new board made by the community and move the original chips onto it. The machine stays the same, with its own case, keyboard and chips.

Difficulty: WorkbenchTime: 8 h

Machine
Original boardReAmiga 1200Kickstart68EC020BudgieGaylePaulaLisaAlice

0 OK, 0:1

Illustrative diagram: the chips sit elsewhere on the real board.

⚠ Before you start

  • Commodore's own chips are no longer made. A chip damaged while removing it from the old board may have no replacement: this is bench work, not a first soldering experiment.
  • Before fitting any chip to the new board, check with the multimeter that there is no short between 5 V and ground.
  • Work with antistatic protection: the original chips cannot be replaced.
ferramentas.txt

Tools

  • Hot air station and fine-tip soldering iron
  • Flux, desoldering braid and isopropyl alcohol
  • Magnifier or microscope
  • Multimeter
  • Antistatic wrist strap
  • The new board made from the project files, and the parts from the bill of materials (BOM)

When it makes sense

A broken trace or a handful of eaten vias can be repaired with wire, and repairing the original board is always the better choice. A transplant makes sense when corrosion has reached many vias and the inner layers of the board, when the board is cracked, or when earlier repairs make it impossible to tell what connects to what.

This is exactly what the ReAmiga project was born for: its author, John Hertell, started by redrawing the A3640 CPU card of the Amiga 4000, which tended to die from capacitor leakage damaging traces and vias. The aim, he says, is not to make new machines but to save what can still be saved from the old ones.

What moves from the old board to the new one

The chips you can no longer find new are the ones that move: Commodore's own chips, the processor and the Kickstart ROMs. On the Amiga 1200 these are Alice, Lisa, Paula, Gayle and Budgie; on the CD32, Akiko, Alice, Lisa and Paula. Everything else on the new board is new: resistors, capacitors, common logic and connectors.

  1. 10Photograph the old board on both sides and note its revision before removing anything.
  2. 20Remove the socketed chips first. Soldered ones, such as the Amiga 1200's QFP processor, come off with hot air and flux, without forcing the legs.
  3. 30Clean each chip's legs with braid and alcohol, and keep them on antistatic foam, labelled.
  4. 40Keep the old board: it can serve as a reference and may one day be repaired.

Building the new board

Each project comes with the files to have the board made and the list of parts. The ReAmiga project also has a tool, the Locator, that shows where each part goes on the board: pick a value and it lights up every position where it belongs.

  1. 10Solder the passive parts and common logic first, following the bill of materials for the revision you had made.
  2. 20Before the original chips, check with the multimeter that there is no short between 5 V and ground and, with the power supply connected, that the voltages at the sockets are right.
  3. 30Fit the original chips last, paying attention to the orientation of each one.
  4. 40Read the revision notes: some boards have parts that are only fitted on one variant, or jumpers that must be closed.

The ReAmiga projects

There are boards for the Amiga 1200, Amiga 3000, Amiga 4000 (revision D, CR) and CD32, and a 68030 CPU card for the Amiga 4000. The 4000 and CD32 boards were made with Róbert Tihanyi. Some add small improvements to the original board: on the ReAmiga 1200, for example, a VGA output, still at 15 kHz, and a Kickstart switch.

The files are open, but the project has no formal licence. The author asks that anyone who changes the project keeps it open, accepts boards being sold as a hobby, asks anyone doing it as a company to contact him first, and refuses rebranding. He only gives support to people who buy boards from him, and warns that it is a hobby project with no warranty whatsoever.

A machine on a new board still has its original chips, but the board is no longer Commodore's. If you sell it, tell the buyer.

When to bring it to us

If your board has corrosion in its vias and inner layers, bring us the machine before deciding. We first check whether the original board can still be repaired, which is always the better choice, and explain what each route involves.

Request a repair

Applies to

These guides are for information. Working on old electronics carries risks: do it at your own risk, with the machine unplugged, and never open power supplies or CRT monitors. If in doubt, bring the machine to us.