- The LaST Upgrade -


Fitting Guide by Jonathan Whiteside

July 30, 2016 - Last updated August 3, 2016


The tools. I used a fairly standard set of small side cutters, temp controlled soldering iron, small forceps (For removing the old PLCC pins), flux, desolder braid, plastic levers (iPhone screen removal tools) and a large eraser. More on that later.

One thing that isn't visible is the illuminated hands free magnifer, which is essential for the fine soldering.

Total work time for this was about 4-5 hours for me, bearing in mind the TOS switcher had already been installed, and I had already preassembled the booster. Personally, I'd do the TOS switcher first and make sure it works before you move on to the booster.


Starting PLCC removal using the pin method suggested by exxos in his instructions. It works, so use it.

All pins lifted. Again, the instructions from exxos worked up to this point. I tried lifting the socket after snipping the leads, but no movement at all.


Since the socket wouldn't lift, I decided to cut it into smaller pieces as per exxos. This is the first 'Gotcha' for me. The socket didn't cut into smaller chunks, it disintergated into small pieces leaving this very tough baseplate behind.

This is where you MUST use plastic tools, or you'll destroy the tracks on your mainboard. This is where the 2 blue plastic levers came in. I had to trim the pins a second time, then work my way around the edge with the levers to lift the baseplate.


It's desolderin time!! Baseplate off, pins ready to desolder.


Follow the instructions by exxos for this part.

TIP:- I used small forceps with serrated jaws for manipulating the pins, as they were easier to handle than the needle nosed pliers I own, which lost grip as the jaws were not serrated. exxos has already mentioned the "Gotcha" around the power pins, take your time, they do take longer to desolder.


This shot is all pins removed, but solder is still present in the thru holes. Again, the PLCC removal guide by exxos is good up to here.

TIP:- TAKE YOUR TIME, rushing will just hurt your chances of a good job.


My next TIP comes here, cleaning the solder from the thru holes. I used 1.5 mm solder wick, and rather than put flux on the board, my flux was quite thin, so I DIPPED the wick into the flux. Get your soldering iron right in the middle of the hole, and on top of the wick. Be paitient, it takes a second or two, but the solder will melt, and the flux in the wick will help it flow, and you'll see the wick turn silver. Don't be tempted to re use wick, it won't work, just regularly trim the used parts away and discard.

TIP:- If a hole doesn't clear of solder right away, move on so that you are not constantly heating the same part of the board, which can damage the tracks and vias.


All cleaned up! I had a few holes that half cleared, the TIP here is to refill the holes with fresh solder, then use the wick again to empty them. Hold the board up to the light to confirm they're clear.


After trimming the pin strips, I dropped them in to the mainboard as a trial run.


TIP:- Here is where the eraser comes in.Put 2 of the inner pin strips into the booster board, then push the whole thing into the eraser, making sure the pins are well aligned. Solder the 2 end pins of each strip. Repeat until all of the pin strips are held in by just 2 solder joints at each end, as this will give you a little wiggle of the pins so you can get them into the mainboard.


Insert the booster, and hold it in place with tape or blu-tac, and solder just 4 of the outside row of pins at the ends.

TIP:- good alignment is critical here, before you move on to soldering the rest of the pins, so just soldering a few will give you a chance to wiggle things around. When you're happy it's all in a good position, solder the rest of the pins on the mainboard side, then the rest on the booster side.


All soldered in, awaiting final wiring.


Wired up to run at 8 Mhz.

All wiring completed, with a switch for 8/32 Mhz and Tos 1.62/2.06. Just need to mod the case for the switches.

Just to the left of the yellow clip, you can see the 1.44 Mb fdd mod, also from exxos, that I installed at an earlier date.


Booting up to TOS 2.06 at 8 Mhz


Booting with TOS206 with 32MHz enabled.