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flea

C

captain

Still lazy after all these years
hi all, i bought a flea project to try and have just started to put it together, I didnt realise how small the surface mount resistors are, i lost two in the carpet immediately. Any tips on soldering these to the board, i didnt realise how bad my eyesight was! they came colour coded in packets but i could find no reference to the colour against its value

thanks
 
Crock clips used to clamp tweezers and the tweezers clamp around the board, I use all sorts of things really, extra pair of hands via the missus. Some times blue tack can help if put in the right place, I work under a strong eye glass that straps to my head to aid sight, looks real weird but it works well. There is no way I could use 0805 with unassisted vision and very bright light.
Running some flux on the board first, not plumbers flux though else the copper rots over time.
Were you using the Flea?

Tony
 
thanks tony, the aim is to put it in my 3.5cd, but it feels a long way, i need to get some more resistors first, an eyeglass will be a help, i used a flux pen. i cant seem to match the colour codes on the resistors either i seem to have a couple spare too, i think i will get it all out again tomorrow
 
Just measure the resistors with a mulltimeter, to my knowledge they are not colour coded, they are marked with digits, there again I have never tried to look.
Make sure you get those tiny parts on first.
I also use a vacuum holder, quite cheap but still a little too large for 0805 size.
I also use my normal size chisel edge iron tip and resist the temptation to get small tips out, but really it’s whatever works for you.
Home territory for the Flea in the CDP
Make sure you follow Martins instructions and check the load currents by measuring across the parallel pair of 1R resistors, it is easy for a high bandwidth AD797 to get oscillating, but again should be at home in DCP clock duty.
Twist all wires tightly

Tony
 
These parts are not critical, captain. You can use a single 'normal' 1ohm resistor, bend and crop the leads and solder the leads to the pads if that is easier for you.
 
I use a large hatpin mounted in the croc clips of a "Second hand" device, which also has a magnifying glass attached. It just takes a bit of patience to align the pin onto the centre of the SMD, but despite being intimidated initially, I now find it quite easy.

Or, you could try my even easier alternative :-

soldering-SMDs.jpg
 
thanks martin i was wandering if i could subsitute, im sure nostalgia will kick in with my plea's.for all the long term modders, i feel strong again though not as strong as deutsche fc
 
Fine. Just use one, 1 ohm resistor - about 10p at Maplin - and fold it to solder to the pairs of pads at each end of the pairs of SMT resistors in the pic handily posted above :)

Or if you can just bridge the pads the traces would connect, like this:

1ohm.jpg
 
Tip for soldering SMDs is to use a pair of tweezers to hold the part in place, put some solder on the iron tip and tack one end of the part, solder the other end properly, go back to the previously tacked end and solder properly. A flux pen helps to.
 
I'm quite shaky but I manage ok usually

Pre-solder the two pads first - it doesn't need a lot.
Then place the resistor on top and gentle press with something small - tweezers.

Touch each pad with the soldering iron, the resistor will probably pop down a little because you are pressing it down.

Same works for op amps, so far anyway
 
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