First ebay Minimig sells for £214 (305 EUR / $428 US)

[McVenco]

sweetlilmre wrote:

Can't tell you how close I am to hitting 'buy it now' on the 2nd auction...

Do it! Do it! Do it! :lol:

[Gavilan]

By any chance...is the dutch guy selling this wonderful kit registered on this forum??

[amazing]

yes the guy is registerd on this forum
his name is wizard66

as soon as my parts arrive i build 3 minimigs 1 for me 2 for any intrested..

[KThunder]

amigadave wrote:
...
I am hoping the Open Source and Amiga Communities will soon surpass anything that Amiga Inc. can come up with.  That will truly serve my sense of justice, after Amiga Inc. have left us with nothing for so many years, we can then do the same to them by making our own Next Generation Amigas via Maxi-Minimig version 5.0 (due out in the first quarter of 2010).

with UAE, AROS and now Minimig i think weve had amigainc buried for years. im betting well see ocs modded to ecs and possibly rtg on the minimig with a diy 020 accelerator before too long.

[taunusand]

I take a deep bow for those who take their interest in building this projekt  :-D

And I hope this projekt finds it's way to little Denmark :-)

[Ohno]

Wizard66 said it took him about 14 hours to build. He put an awful lot of effort in it and it really shows.

Very nice work.

[whiteb]

I can vouch for the time taken on the making of the boards.

Those 0805 Capacitor's and Resistors *REALLY* take time because of their size

[JosephC]

It is such a shame that these incredibly expensive minimigs can never be upgraded to AGA due to the fundamental design flaw of 16-bit video output.   :madashell:

AGA requires 24-bit video output.  :rtfm:

[nBit7]

Those 0805 Capacitor's and Resistors *REALLY* take time because of their size

0805 (2mm x 1.25mm) Rs and Cs, Yes they are small but it should not be taking too much too individually (unless you are tring to perfectly align thenm).  Ok, I will admit it does take a bit of practice to get quick at it.  But after a few minimigs you should be quite good at it.

0603 (1.6mm x 0.8mm) are not too bad.  
0402 (1mm x 0.5mm)  now thats getting a bit hard without magnification buts its the most common size now.  
0201 (0.6mm x 0.3mm) now thats small.  
01005 (0.4mm x 0.2mm) I don't think I would even bother attempting.

I don't know what method you are using.  But the quickest method is to use an ordinary soldering iron:

1. solder a small amount of solder too one pad only
2. place the part next to the pad (such that is is over the other pad) then hold by the sides with tweezers.
3. heat the pad with the iron on the outside edge of the pad.
4. slide the component into the pre-soldered pad
5. remove iron, wait a few sounds then remove tweezers
6. solder the oppersite side.
7. add a little more solder (or flux) to the first side if needed

[koaftder]

I'd say someone with some basic skills who is familiar with smt stuff should be able to put together a minimig in about an hour.

I only took me about 5 minutes max to lay down the fpga, and thats the hardest component on the board. As small as the leads may be, you still don't need any magnification or special tools to get it on there.



flux the pads
rake the iron across the pads to build up a layer of solder
center the chip on the pads
tack down two corners
double check the centering
get a tiny solder ball on the tip of the iron, place down the iron at the start of the pad and trace it along the pad until it bumps the lead, you'll see surface tension on the solder work it way up the lead, etc.

For the chip resistors and caps, I smear some paste on both pads and build up a thin layer of solder on both of them. I then center the device on the pad, press down on it and hit one side, then i do the other and then go back and hit the first side again. Actually, I add the solder layer on all the pads for all the device before i start, that way it only takes a few seconds per device to tack them down.

[whiteb]

nBit7 wrote:

1. solder a small amount of solder too one pad only
2. place the part next to the pad (such that is is over the other pad) then hold by the sides with tweezers.
3. heat the pad with the iron on the outside edge of the pad.
4. slide the component into the pre-soldered pad
5. remove iron, wait a few sounds then remove tweezers
6. solder the oppersite side.
7. add a little more solder (or flux) to the first side if needed

For the 0805's, thats EXACTLY the way I did it.

[nBit7]

rake the iron across the pads to build up a layer of solder

If you get the boards finished by HAL (Hot Air Leveling or HASL). Then you can skip this step.   HAL is where the pads are all pre tinned and the excess solder is blown off with hot air.  This is the best finish to get for soldering too.

Personally If I put solder on the pads first I use solderwick (braid) to remove the excess.  Untherwise the IC is harder to place and may sit too high above the pads.

center the chip on the pads
tack down two corners
double check the centering
get a tiny solder ball on the tip of the iron, place down the iron at the start of the pad and trace it along the pad until it bumps the lead, you'll see surface tension on the solder work it way up the lead, etc.

It should be noted that you need a solder with a good flux for this to work well.  Or use liquid or gel flux.
Or anther way is too use lots of solder (and hence lots of flux from the solder).

[koaftder]

I don't bother wicking sub mm traces as they don't build up significantly, on larger traces, definitely. One needs to be mindful of using the braid on thin traces as if it is allowed to cool it is very easy to accidentally lift traces off the pcb.

Pre-tinned boards are definitely more convenient.

Flux is definitely important. I always apply flux to the pads  after tinning which helps prevent the part from sliding around as much and much and makes the solder adhere to surfaces much better. I recommend being minimal with the solder and liberal with the flux. It is far easier to remove the excess flux than it is to clean up gobs of solder bridges on a qfp.

One thing I have been wondering about is the method of tinning one pad, tacking it down, and then going to the other pad and applying solder. This method would appear to make sure the part is level with the board.

When I do it, I tin both pads, solder one side, then the other, and go back to the first side again. This is much faster than having to hit one side with the iron and push a wire of solder into the other side.

So the way I do it, when I hit the first side and press down, its going to tack down at a slight angle. When I do the other side it should tension the opposite side right? Thats why I go back to the first pad and hit it again, to make sure it's not in tension. Is this necessary?

[weirdami]

Funny... after all those companies failed to deliver new Amigas in all these years, the users finally decided to build them on their own....

The biggest funny is that Dennis wasn't even an Amiga user and had never done an FPGA before. MiniMig was his case study on how it all works. (From what I gather.) Had the Amiga spirit inside all along, turns out.  ;-)

[nBit7]

One thing I have been wondering about is the method of tinning one pad, tacking it down, and then going to the other pad and applying solder. This method would appear to make sure the part is level with the board.

I just solder one corner pad.  Line the chip up.  and heat that one pad (I don't worry about height at this point).  

Then go to opposite corner and gently push down (if its not lining up at this point then heat the first pad and adjust)
Then tack one of the pins down.

Go back to the first joint and heat and push.  The chip should now be level.  You may wish to push and tack the other corners too.

[countzero]

there's one thing I wonder about minimig building. PIC and the FPGA must be pre programmed. programming the PIC would not be very difficult, but how do you program the FPGA ? or is it programmed dynamically every boot by the PIC from some media ? (sd card ?)