As many of you know the solder joints for the key switches on the Scorpius M10 are very bad. I had one of the keys on my M10 quit working so this was the first time I have had the displeasure of actually taking a look at them.
Having worked as a SMT and Through hole process engineer for many years (before the dot com bust) I can make an educated guess as to what their problem is. And I can say this much they need to fire their current process engineer.
From some tail tell signs on the board it looks like they are doing a two stage process.
1) Place all parts except the key switches and the mounting plate I would image and run that over the wave solder machine. Most of these solder joints look halfway decent. They do have an issue where the daughter card is mounted to the board as I can see signs that they did a little rework on some of them. I bet due to bridging. The pins are awful close together for wave solder work. But it is more cost effective to just rework them than it is to move to another process for that one part.
2) Mount the key switches and backing plate to the board. With out a scope it is hard for me to determine the exact process here, with a good scope I could tell you for sure which one. Any ways at this point they are doing one of two things:
a) Using a selective soldering machine
b) Hand soldering the joints
My bet is with option b because of the inconsistency of the joints. The number one cause of the solder joint inconsistency is lack of heat control in particularly the lack of preheating the board and switches before doing the hand soldering. To get a really good hand solder you have to heat both the board and the part. If you don't you get the kind of solder joints I'm seeing on the back of this board.
Actually after taking a look at this
http://www.cherrycorp.com/english/switches/key/mx.htm which states that the switch can be exposed to a 500F wave solder for 5 secs. I wonder why they are not wave soldering the whole board. Oh I forgot I bet they are using a lead free solder which means the wave solder is going to be 600-700 depending on the formulation they are using but still I bet you could wave these boards you would just have knock the exposure time down a little so the switch pins don't over heat.
Oh well I'm just ranting I really hate to see this kind of sloppy work. I tried to take some pictures of the issues and maybe explain what the cause for those issues are but I could not get the right lighting for taking some good shots. I will try to get some good shots of the joints during the weekend if anyone is interested. But I have to warn you I may be Monday before I can actually get them posted as I'm going on a cub scout camp out this weekend.
