need to solder and resolder atleast 40 times on smd pads?

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ton88

Joined Nov 10, 2019
17
Short version i have 20 IC's i need to remove from there current pcbs and solder them onto a programming board and solder them back onto there pcb they came from, would you think the smd pads on the programming board would last or should i be concerned about damage to the programming board pads?

i didnt make them configurable i didnt account for this when i designed the pcb and didnt put any dip headers to any i2c,spi,etc pins,iam stuck with soldering wires onto a TQFP-E 128 pin 14x14 @ 0.4mm pitch which my soldering skillset is limited and i dont think i can do it 20 times.My next plan was to get a Eval board for my IC and take the IC from my pcbs and solder them into the eval board change some settings via PC software on the IC then resolder the IC back onto my pcbs.I was also thinking breadboarding everything and ditch the eval board, i would use a plastic socket programmer some voltage regs. and a arduino to send my i2c messages.Not sure which way to go with it any other ideas or input is appreciated
 

Irving

Joined Jan 30, 2016
2,196
I'd probably use low-melt solder and a good no-clean flux for the temporary connection and hot air rather than an iron for the actual joints. Use a good quality flux and wick to clean off between chips. The pads should hold up OK as long as you're gentle.
 

Ian0

Joined Aug 7, 2020
3,524
Make sure that the solder really has melted before you try to lift them off the board with tweezers. if you don't, you'll pull the tracks off.
 

MrSalts

Joined Apr 2, 2020
655
Use a test socket to program. Set up the test socket to link to your programmer with a small board that you can solder to the test socket clamp the chip in and program. If you are programming anyhow, you might want to use new chips if they are not too pricy. If they are pricy, use some good solder wick to clean up the pins before clamping them into the test socket.
Something like this - or something from a more reliable source than aliExpress.
https://www.aliexpress.com/item/745088120.html
 

dendad

Joined Feb 20, 2016
3,924
As @Irving says, use hot air.
A reasonable hot air rework tool makes SMT work a lot easier!
With one, you can handle SMT parts quite easily. I'd not be without mine.
It may be a good idea to practice on an old SMT board for a bit just the same.
Mine is a soldering iron/hot air combo from Ebay and it has had a lot of use.
There are many types and are quite cheap now.
Oh, they are great for heat shrink tubing too!
 

DickCappels

Joined Aug 21, 2008
7,905
One way around the problem, if the on-board circuitry does not prevent it and if your chip is in—system programmable is to tack wires the necessary pins on the chip and connect the other end to a programming connector.
 
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