tkc8800

Technology and retro computer blog

Amiga 500 rescue

I recently rescued this Amgia 500 from being recycled.  It looked like it'd been dragged through a river.  It was reasonably complete and surprisingly not broken.  I also managed to get the power supply, but both cords had been cut off.  I figured it most likely wouldn't work but it'd be fun to tear it apart and see what was inside.

 

The first thing I did was brush the dirt off the top to see what was under it.  There were a couple of missing keys but it started to look reasonably good.  With most of the thick dirt off I started to take it apart.  I noticed that the warranty stickers were still in tact so it doesn't look like the machine had ever been opened before.  This was a good sign as I expected that it was complete on the inside.

 

Amiga Amiga Amiga

 

On getting the top cover off it started to look pretty bad, it was really dirty inside and the RF shield was very rusty.  I took the shield off to expose the motherboard which looked a little better.  I could see that the bottom part of the RF shield was also pretty rusty, so I figured the motherboard would be damaged.  It looked like water had leaked into this machine at some stage and sat there for quite a while.  When I removed the motherboard I was surprised to see it had survived due to the plastic insulation sheet between the motherboard and the bottom RF shield.  After a quick brush off the motherboard looked really good.  There was some surface rust on the rear connectors but that was all.

 

All the chips were in tact and it also had a memory expansion module installed.  The clock battery on the expansion module had leaked and there was some leakage on the clock circuitry.  The internal floppy drive looked reasonably good.  I removed the memory expansion card and the floppy drive.

 

Amiga AmigaAmiga

 

I removed the bottom part of the RF shield, the rust from the bottom shield had covered the bottom part of the plastic case.  With the functional bits removed I figured I'd do a quick test to see if the machine would power up.  With the cords cut off the original power supply I used an ATX power supply instead.  I looked up the pinouts for the power connector, I recall from past reading that the Amiga 500 power supply can be replaced with an ATX supply so I knew it had all the necessary voltages.  I plugged in an old Amiga RGB to scart cable that I had in a box of parts.  I haven't had an Amiga 500 for over 20 years but I managed to get an RGB/scart cable with a box of parts I picked up a while back.  Luckily I kept the cable.  I connected the cable to a small LCD TV that has a scart input and on initial power-up all that I got was a white screen.  I did a web search about Amiga's with white screens and there were several reports relating to water damage and chips not seated properly.  I re-seated all the chips but no change.  I eventually had the idea to connect the Amiga's mono video connector to the composite input on the TV and I was greeted with a workbench disk screen.  The issue with scart cable was that my LCD TV didn't support RGB through scart.

 

Amiga

 

I found this very motivating as it showed that the machine was doing what it should.  I cleaned up the floppy drive and plugged it back into the machine and on subsequent power tests I got it to the point where the drive would spin ready for a disk.  This all looked very promising.  Not having been involved with Amigas for over two decades I had no software to test it with so I started doing some web searches on getting software.  There are utilities around that will transfer software from a pc to the Amiga but these only work if you boot the Amiga with a Workbench disk first.  I borrowed a copy of Workbench 1.3 and managed to firstly boot the machine and then use it to copy the existing disk, everything worked fine.  With evidence that the machine seemed to work ok, I got stuck into cleaning the case and other parts.

 

AmigaAmigaAmiga

 

AmigaAmigaAmiga

 

AmigaAmigaAmiga

 

Once cleaned up the case came out looking really good.  I got the rust off of the RF shield and the bottom case and re-assembled everything. I also created a better power plug for the ATX supply.  I extracted four pins out of a round DIN connector and soldered them to an ATX molex lead.  Since re-assembly I've connected the Amiga to my pc and used Amiga Explorer to transfer disk images across to it.  The process worked fine.  The memory expansion card also works fine, I removed the leaky battery and cleaned up the board, it now reports an extra 512k of memory.  The Amiga boots reliably and I've since tested it with a couple of games which worked fine.

 

1st November 2015

After the success with the main machine, I tested the power supply.  I hooked up a mains cable and checked the output voltages and all voltage were fine!  I've re-attached the mains cable to the power supply and I'll need to get hold of an Amiga square 5 pin power connector to fix the cable to the machine.  These plugs are not easy to come by so I'll have to attach the makeshift version until I can get one.  The A500 was perfectly fine, aside from rigging up a power supply and cleaning nothing special was done to get this machine to work.

 

Amiga Amiga


15th November 2015

I've now replaced the missing keys and created a good makeshift Amiga power cable.  I've also added a Gotek floppy emulator which allows loading of ADF images from USB stick.  I mounted the Gotek on top of the Amiga using some double sided tape.  I passed the data and power cables for the drive through the back of the case.  I still have the original floppy installed but just un-plugged.  I think this is a much better solution than hacking up the case to fit the Gotek internally.  This way you can revert the Amiga back to it's original configuration.


Amiga Amiga Amiga

Comments (7) -

  • DesktopDynamite

    8/1/2016 6:15:33 PM |

    Hi there nice catch and good job on restoring this classic computer. I have also rusty RF shields lying around. Could you pls give me info on how you removed the rust? Did you paint it?
    Tnks.

  • Theo

    8/1/2016 7:00:06 PM |

    Hi,
    To get the rust off I used a power drill with a wire brush attachment.  It's very hard to remove the rust by hand with steel wool or something similar.  So I'd recommend using some sort of power tool.  It's also dangerous doing it by hand as these shields have very sharp edges.  Wear gloves!

  • Sergius

    8/1/2016 10:26:46 PM |

    Excellent job.
    I'm very impressed.
    Congratulations.

  • Matt Costanza

    8/2/2016 2:34:28 AM |

    This is fantastic. Amazing clean up.

  • Harlan Gerdes

    8/2/2016 4:36:24 AM |

    What revision was the motherboard? I have a version 5 and the power led blinks 10 short blinks and one long blink then repeats. It never shows anything on the monitor though. Anyway, great job on the restoration! It looks really nicely done.

    • Theo

      8/8/2016 11:37:54 AM |

      Not really sure about the revision of the motherboard.  There is one photo above where you can see the mb clearly and there's some numbers on the bottom left of the board, you may be able to tell from those.

  • DesktopDynamite

    8/8/2016 12:13:33 PM |

    It's a rev 6A motherboard.

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