Amiga Repairs: Put Down That Screwdriver!
The 16bit era Commodore Amiga computers have many of their ICs socketed, which means they can be removed easily when repairing or upgrading the machines. I’ve seen many use screwdrivers to remove the chips, and whilst this can work in a pinch, there is a high risk of damaging the chip or socket. Today I’m going to walk you through some of the tools I use instead.
Probably the most precious chip in a 16bit Amiga is the Agnus. It is essentially the memory controller and co-processor for the system. It is a socketed PLCC-84 chip and on some motherboards it is a very tight fit in the socket. Using a screwdriver to lift it can easily crack the socket which will then cause a bad connection between the socket and chip. There are cheap tools which can extract the PLCC by squeezing them such as this one. The cheaper tools can easily buckle for the tighter fitting chips and they can scratch and damage the chip.
With this in mind I went on a search to find a tool that would perfectly extract the chips. I found one by Piergiacomi in the EU (Hakko in USA) and sold by Kaisertech in the UK, who I usually order my soldering tools from.
This tool is amazing, I use it very often when testing RAMesses boards. Here is a video of it in use with a very stubborn Agnus that no other tool would pull. Despite the pop there is no damage at all to the chip or socket.
There was a period of time where I was building many Terrible Fire TF536 boards. When it comes to testing these boards I needed to pop in my known-good 68030 CPU and remove it again. The 68030 is a 128pin PGA chip and lifting it with a screwdriver is very risky. The solution is an AMP 58113-5 which is available on Mouser. Unfortunately at time of writing is is more than 3x the price of what I paid for it, and the image on their site isn’t correct. But it is a really great tool (the second tool in the top image of this post).
Not only does this tool make removing PGA chips very easy, but it is also incredibly useful for machined-pin boards such as accelerators when they need to be removed from CPU relocators without damaing the pins. Another thing I do often when testing TF536 boards.
Wera Chip lifter
Wera are well known for their screwdrivers. They are amazing and I wish I had more of them than I do (their advent calendars are awesome too!). But they also make the Wera Chip Lifter. This is very much like one of thier screwdrivers, but has a deliberately bent and forked end on it perfect for getting under and lifting ICs. This one in particular is incredibly useful for removing 68000 CPUs from their sockets and other things the tools in this post does not cover.
If you are a Wiha person instead, you are in luck! They make an almost identical one.
There is something in the design of this tool that makes it significantly easier than a screwdriver to remove an IC and it doesn’t scratch anything along the way.
Whilst the Wera Chip Lifter is a great general purpose tool, sometimes it is useful to have a specific tool when you are repeatedly removing DIP chips. Sunhayato make a range of tools for this and the GX-7 works with the large DIP chips in an Amiga.
Here is a video of it being used to pull a tight fitting Paula.
No bent pins, no damage to the socket, nice and simple. This model works on the 40 and 48 pin DIPs in an Amiga, but Sunhayato also make the GX-6 and GX-3 for smaller chips and I’ll be getting these models soon.
Amigas are very old machines with ageing sockets and chips that can all be damaged easily. This is why I really recommend using the right tool for the job to help preserve it all for years to come.