A little late weighing in on the subject. I find desoldering braid is easy to use and removes more of the solder than the vacuum type desolder tools. It is copper braid that you hold against the solder joint with a hot solder iron. When the solder reflows, it is wicked up the braid. The surface tension of the solder is enough to pull just about all the solder out of the throught hole. Nice clean pad and hole to work with. It is cheap and available at radio shack or any other place soldering equipment is sold.
Thought I'd come back here after I had assembled my first two kits, and post some useful information.
1. For me, instead of using tape to hold down chips and other components, I just put solder in one of the end pin vias in the board, then insert say, a chip, and of course, the via with the solder in it keeps that one pin (and maybe two others) from going all the way in, then hold the IC (or whatever) from the opposite side, and touch the via with the iron, letting the pin slide in place, remove the iron and wait a couple seconds, and your part is now tacked down for you to solder the rest of the pins. A couple warnings when doing this: Make sure and touch up that first pin, as it may not have enough solder on it, secondly, if using this method for the headers, make darn sure you aren't holding the one pin you are tacking down with your other hand, or you will be reminded quickly. I'm not sure why I like this method, maybe sometimes it is because the tape doesn't always work, then you get a crooked chip.
2. If you are like me, then you ended up with at least one component that has multiple pins, with only one pin soldered down. Now I understand the importance of checking out the board before installing the high power heat sinks, but it just seemed like a lot of work to me. I ended up with one of the resistor packs not being soldered down, next to the RS485 transceiver. Instead of removing the heat sink, I just bent it over about 20 degrees, and soldered it from the top side of the board. This should work for most components, at least, the ones you can access the pins on, from the top side.
Well, I guess there weren't that many things I was going to share. I also ended up using Arctic Silver 5 for my heat sink compound, as I had a lot of it lying around, not being used, and I figured it was better than the stuff in the kit...not that they will be getting that hot, with LED lights on most channels...but oh, well.
I also found a tool that I will be trying out on the next 3 boards, called a Double Sided, Lead Bending Gauge. It allows you to make repeatable bends for those through-hole components.
Not sure how useful it would be, of course, it would have helped if all the resistor footprints on the layout were the same size, but I think the general size can be determined by eyeballing it. It should be either 0.400", 0.500", or maybe even 0.600", or maybe even half sizes in between.
The CTB16PC instructions says the resistor networks do not go in a specific direction.
The instructions state the following (page 14):
NOTE:
The orientation of resistor networks R1, R15, R16, R18 & R19 is NOT important.
jeffmill wrote: markm wrote: snip...My biggest problem: mounting the resister packs correctly (got one backwards). De-soldering an 8 pin pack is NOT FUN.
I soldered R2 in backwards and caused the board to fail. This is a very good tip! I've noticed the instructions now have a highlight about getting the orientation right on the resistor networks. Please take your time and make sure you get the parts placed in the right direction. You'll be glad you did!
This is a misleading statement, just as the statement from the manual is. R2 is bussed and must be installed in the correct orientation or damage will occur to the 8 pin comm dip.
If you look at my post closely it states R2 as the offending chip. Mr. Baldwin was at my house when the comm chip failed and witnessed this first hand.
Jeff
stanward wrote: The CTB16PC instructions says the resistor networks do not go in a specific direction.
The instructions state the following (page 14):
NOTE:
The orientation of resistor networks R1, R15, R16, R18 & R19 is NOT important.
jeffmill wrote: markm wrote: snip...My biggest problem: mounting the resister packs correctly (got one backwards). De-soldering an 8 pin pack is NOT FUN.
I soldered R2 in backwards and caused the board to fail. This is a very good tip! I've noticed the instructions now have a highlight about getting the orientation right on the resistor networks. Please take your time and make sure you get the parts placed in the right direction. You'll be glad you did!
jeff
Last edited on Thu Oct 1st, 2009 11:35 am by Jeff Millard
____________________ Evan... Are you at home resting yet? I'm very glad you're feeling better!
stanward wrote: I can't find an R2 on the board.
R2 is part of the Unit ID switch circuit on the CTB16D, its orientation is important. Orientation is not important for the other resistor SIPs. The CTB16PC does not have Unit ID switches so R2 is not present.
