POLL: Best way (the proper way) to solder a diode to a circuitboard?

[hubcap]

yeah man, many ways to skin this cat.
by no means is there a "perfect" way.....even if using J-Std guidelines. Many methods work....it all depends on how anal you want to be and if its for commercial use or not...(AND if it needs to pass UL)

he could attack this in many ways, and all would be successful.

Just wish they would chime in....

 

[AZMSGT]

Both done by hand. Not a drop of flux.
Using lead free (with the exception of the reworks)
Pay no mind to the cockeyed common mode choke and the crummy rework. I was having an off day
2nd pic is a prototype and had some components that were larger than the pads so it made things tricky, but, it works.

I’m not in any place to comment anymore on anyones work. I haven't touched a PRC 2000 in 15 years.

To me, it looks like the OP tore the lands off the board when he chiseled it.

 

[hubcap]

Im considered the crazy one in the lab because I still -like- soldering.
Some of the stuff I do they call "capillary surgery"
They look at me crazy when I tell them I can do 02 and 04 pitch parts by hand.

 

[JonJ]

That’s an Orphek board. I use thermal paste on the back of the led and solder the + and -. I had the original v4s and had some leds go out. I replaced a few with no issue. They have changed to higher wattage leds in the v4 boards and the new ones seem to be better as they aren’t being maxed out like the originals.

 

[hubcap]

To me, it looks like the OP tore the lands off the board when he chiseled it.

that worries me, too.
I wasn't sure if that was a chisel or a (really clean)solder tip.....

see if they chime in and fill us in with some more details.....
looks like we have a lot of lead heads in here that can give them a hand.

 

[hubcap]

That’s an Orphek board. I use thermal paste on the back of the led and solder the + and -. I had the original v4s and had some leds go out. I replaced a few with no issue. They have changed to higher wattage leds in the v4 boards and the new ones seem to be better as they aren’t being maxed out like the originals.

since you've been down this road, are you saying that the center (underneath) needs to be soldered as well as the leads themselves? hard to tell from the pics and I don't have first hand knowledge of the LED hes questioning like you've got....

 

[AZMSGT]

OP original post to help fill in what he has done.

Best way to remove a thermally-GLUED diode from PCB circuitboard

Whats the best way to remove a thermally-GLUED diode from PCB circuitboard.....that has this form factor? Looking for a professional way to minimize damage to the circuitboard (I know the diode will be destroyed) other than just prying the sucker off with brute force using pliers

www.reef2reef.com

 

[JonJ]

since you've been down this road, are you saying that the center (underneath) needs to be soldered as well as the leads themselves? hard to tell from the pics and I don't have first hand knowledge of the LED hes questioning like you've got....

It does not. It is the contact point for the heatsink. Use some arctic silver thermal adhesive to glue it down and then solder the contacts. Make sure you have the positive/negative orientation correct before you solder the new diode on.

 

[hubcap]

Okaaaay….
NOW I see what they were getting at.

Youre exactly correct....if no SOLDER connection is needed, thermal paste would absolutely be in order to do this correctly.
(I was assuming a solder contact instead of a thermal paste transfer method.)


Thanks, @JonJ for the info!

 

[lilgrounchuck]

that old school Radio Shack (shame it folded) solder probably already has flux in it. Pull a strand off and see if its hollow.....might not even need the toothpaste.

No, it’s solid and flows all wonky without the flux.

 

[Thespammailaccount]

Gum and duct tape

 

[ZoWhat]

@hubcap
@lilgrounchuck
@JonJ
@Carlosroach

Sorry for the late response...

Yes what you see in the original pic are a few things:

1) that's a SB Reefing Light (Chinese BlkBox) Retro circuitboard with IMO waaaaay too many 14k & 20K white diodes since my tank is zoas/palys dominated

2) I'm looking to replace all the 14k/20ks with mainly blue/cyan 440/490nms

3) I bought FOUR circuitboards for three lights figuring my first attempt I'll reeeeeeeally screw the first one up. Then being better educated, the remaining three will be nicely done. If i nail the first one then I'll have a spare

4) So I've already kinda SCREWED up because in removing all those 14k/20ks...they were GLUED down with thermal.paste adhesive and wouldnt come off easily. I did it COLD by not heating up the +/- posts. I took the 1/4in chisel you see in original pic and lightly TAPPED each diode from underneath its main body. Each one POPPED off very easily and popped off cleanly. PROBLEM is, like was mentioned, did I do damage to the "pad" where the soldering happens (?). If a "pad " pops off still attached to a + or - post, is all LOST? Can it be repaired?

5) Equipment and solder and diodes

6) WHAT METHOD? I'm confused bc my poll is almost 50/50 on these two approachs

METHOD #1:
Heat up a droplet of solder and place it on the contact pad. Allow solder to cool. Once both + and - contact pads are ready, place the thermal-pasted diode so the +/- diode posts sit ATOP the cold solder. Apply heat using the tip to allow to diode post to MELT DOWN into the contact pad

METHOD #2:
Place the thermal-pasted diode on the board where the +/- contact pads have not been soldered yet. Once the diode is in place, put a droplet of solder OVER the + or - post allowing solder to slightly overflow. The result is a BUBBLE of solder where the solder contacts to post terminal and the contact pad

>>>>I have NOT started this project bc I want to see the general consensus on what method to use... or even a 3RD METHOD I'm very open minded to



.

 

[AZMSGT]

My experience is to:
Clean everything with Iso Alcohol.
Apply very small amount flux to pad
Place new component on pad
Using a wet sponge clean hot solder tip
Apply a little solder to iron tip
Touch tip of iron to pad and component lead, creating a heat bridge add just a small amount of solder as needed.
The solder should wick and your done. Quick and easy.
When finished clean everything again with Alcohol, let dry and apply conformal coating.



If you make a mistake and apply to much solder. Remove the solder using a multi stranded wire with a little flux on it. Apply heat to the wire and the solder will wick up the wire away from your mistake. There is a special braided wire to do this and other tools but the above method works in a pinch.

Yes, a circuit card can be repaired. I used to repair multi layer cards all the time. You need some trace material and you make a new pad. Then you solder it on to the old trace and epoxy it down to the board. This isn't a skill you learn over night and takes a fair amount of practice to get right.

This Manual can teach you

https://www.robins.af.mil/Portals/59/documents/technicalorders/00-25-259.pdf

The asterics are the letters A F No idea why the swear filter blocks it.