Importance of soldering order?

[jpm83]

I have usually solder in first resistors then caps and after that all of the active components. My question is that can I leave the soldering of the resistors last because I haven't got then yet. Can Something go so badly wrong if I do that last, that I should wait resistors to arrive?

Janne

[gez]

You can do it anyway you like, it's just that it's easier to do it in the order you mentioned (though I tend to leave caps till last).  With all the other components in place, your resistors will be prone to dropping down a little, so when you solder and flip the board back over you might just find they're a few mm off the board.  A way round this is to tape the resitors to the board to prevent them slipping while soldering.  The order won't make any difference though.

[petemoore]

  The circuit doesn't do or 'see' anything [active circuit] until power is applied, wiring 'order' is something it won't 'remember'.

[R.G.]

The only real danger is that any MOS parts like CMOS logic or MOSFET transistors will be damaged by static electricity before you get your resistors in. Wrap the board in conductive plastic if you have it or cotton cloth if you don't and put it aside. Synthetics and plastic films that are not conductive cause static damage. Natural fibers like cotton are much less susceptible.

I solder by height. First jumper wires, then axial resistors and diodes, then ICs, then low-height caps, then higher caps. This lets me place all the parts and put a piece of cardboard over the parts to turn the board over for soldering. The cardboard keeps the parts in place without clinching the leads, and if all of the parts at one stage are the same height, the cardboard keeps them seated against the board.

[Sir H C]

I solder by height.

+1.  You can flip the board and all the resistors will keep each other in place, if you have some taller stuff on there already, then it is harder to be sure the resistors are flat to the PCB when you solder.

[StephenGiles]

This comes up frequently - I solder by section so that I test as I go. What I normally do is use the soldering sponge to hold in the components of different height when I turn it over to solder. As to leaving resistors to last..................only when there's an R in the month

[Paul Marossy]

I just start at one end of the PCB and work my way over to the other end. I usually pre-populate the majority of the PCB before I start soldering. I also always use sockets for transistors and IC chips, and they go in last, after everything is soldered in. 

[jpm83]

Thanks for answering, the issue I was a bit worried about is if the heat could damage trannies when soldering in resistors.

Janne

[gez]

Thanks for answering, the issue I was a bit worried about is if the heat could damage trannies when soldering in resistors.

If you have a tendency to solder for too long and the resistor pads are close to legs of a trannie/whatever, you can always apply croc-clips to the legs of said trannie to shunt some of the heat while you solder.

[GibsonGM]

If you're not connecting the R right to the tranny, heat should be no problem, at least any more than it would be if you'd put in the R's first and were then installing the tranny.  I apply heat to a transistor for no more than a 3-count, and allow at least a 5-count before doing it again - have never had any problems.   You can also clamp a little heatsink to the tranny legs on the top side of the board to isolate it from heat applied down below; might give a larger margin of safety if you have the room.  Some people use sockets for this reason - I always use them for IC's but not trannies. 
 

[The Tone God]

I solder by height as well.

Andrew

[WelshWonder]

I solder to height as well, it's a pain in the arse when they hang down when you flip the board over, only way to stop it is bend the legs od the smaller components to stop it, but that's more work.

For some reason though, I really enjoy soldering electrolytic caps (and got to stop myself from doing them first), don't know why, I gues cos they look the ducks nutts.