trouble with heater meater

[Troy Schenk]

hello I'm pretty new to this so I'm sorry about the simple question but I put together a kit and now it sizzles when powered on the ras pi is ok as I took it separate but not sure what I did wrong with the solder job

attached are some pics any ideas?

 

[JSiravo]

give it a good cleaning with some isopropyl alcohol. try to get 99%. 90% works as well. you have flux everywhere and it needs a good cleaning.
https://www.amazon.com/99-Isopropyl-Alcohol-Antispetic-Solution/dp/B00BWYM006

second the soldering around the 12v needs a touch up on all pins. same with the probes. you need to have a nice flow of solder on both sides.

lastly the ATmega socket was soldered in backwards and needs to be pulled and flipped around. i did the same thing on my build.

can you tell where its smoking from?

 

[Steve_M]

Based on the image below, I see the following:

Problem: Gobs and gobs of flux everywhere
Solution: Scrub the board down with some 99% isopropyl alcohol

Problem: Cold solder joints
Solution: Re-heat the joint and allow the solder to flow onto/into the pad and the leg of the component

Problem: Too much solder in places
Solution: Solder sucker or solder wick

Problem: Not enough solder in places
Solution: Re-heat the joint and allow the solder to flow onto/into the pad and the leg of the component

Problem: Leads folded over with excess solder rather than being properly trimmed
Solution: In the future, don't fold over the legs before soldering them, simply trim off the leg past the solder joint.

 

[Andy Snider]

lastly the ATmega socket was soldered in backwards and needs to be pulled and flipped around. i did the same thing on my build.

I wouldn't suggest this. Unsoldering the socket is a PITA & risks burning traces. If it's just the socket that's backwards, it's fine. Just put the ATmega in correctly per the PCB & it will work. It's just straight pins, not keyed or crossed in any way.


The sizzling sound could be flux & not that big of a deal - assuming everything works. You've got multiple issues to address to get any diagnosis.
As Steve said, you have a lot of joints that look 'cold' - not shiny, meaning the solder didn't wet the pin or pad. You want the pin & pad hot enough to melt the solder - not the iron melting the solder and just blobbing. Then it will flow where it needs to go. Clean the flux. Reapply a much smaller amount & hit each JOINT again (not the pin, not the pad, both = joint). Sometimes I watch the backside of where I'm soldering & wait until solder flows. Easy to melt stuff that way, but can help when you have a stubborn spot.
The bent over leads make it easier to hold in place to solder, but you have a lot of shorting risks from the picture. clip those & resolder.

 

[JSiravo]

I wouldn't suggest this. Unsoldering the socket is a PITA & risks burning traces. If it's just the socket that's backwards, it's fine. Just put the ATmega in correctly per the PCB & it will work. It's just straight pins, not keyed or crossed in any way.

Wish i would have known this during my build.

 

[Andy Snider]

Wish i would have known this during my build.

Ask me how I know...

 

[Steve_M]

The DIP socket for the atmega isn't directional. It's got the half moon cutout to help you figure out what way the chip should go, but there's absolutely no need to remove the socket if it's backwards. The chip will still fit into it fine.

Also a little tip for holding components in place. Silly putty or blu-tack works wonders!

 

[WBegg]

or one of these ....

 

[SteveCK]

If I had to guess I'd say you're probably using the wrong size solder too. Looks like you're using the large stuff for soldering home wiring or the like. You want solder that is 0.031" diameter so you can control the amount you use better