Need help, getting this solder to melt

dl324

Joined Mar 30, 2015
15,458
Welcome to AAC!

What type of soldering iron and tip are you using? You're going to need an iron with fairly hefty thermal mass and wattage and hold it on the joint long enough for the solder to melt.

I'd use a solder sucker to remove the molten solder. You could try solder wick, but that'll just add to what you need to heat.
 

MrChips

Joined Oct 2, 2009
27,686
Welcome to AAC!
Please note that we get dozens of new threads started every day.
Thank goodness everyone does not put a title “Need help” even though every thread is asking for help.
Please be considerate and give your thread a title with some meaningful description of the content of the thread.
 

SamR

Joined Mar 19, 2019
4,492
There is also a solder alloy that aids in removal SMT Removal Alloy 4.5ft: Amazon.com: Tools & Home Improvement. Once the solder starts to melt it is added and acts as a "solvent" and lowers the melting point.

I am also a big fan of my Desoldering Vacuum station... Pro Digital Vacuum Desoldering Station, Anesty Professional Removal Rework Station ZD-915 Iron Gun Built-in Vacuum Pump - - Amazon.com available cheaper at places like AliExpress. Messy to maintain but does a heck of a job removing solder.

Then in extremis there are butane and propane torches... Use wisely and sparingly!

And Welcome to AAC!
 

Ian0

Joined Aug 7, 2020
6,711
How much of it needs to continue working after you have removed it?
A hot-air gun for stripping paint will desolder anything. How much of it will still work afterwards is more debatable.
 

Thread Starter

coolsun67

Joined Oct 22, 2022
10
The whole thing needs to work. It's a 1600 dollar board. It's part of a reefer. I have to get it apart so I can test the other components.
 

MrChips

Joined Oct 2, 2009
27,686
The whole thing needs to work. It's a 1600 dollar board. It's part of a reefer. I have to get it apart so I can test the other components.
FYI that is not how we trouble shoot and diagnose a bad system.
We look at functionality, take voltage measurements and look at total and partial circuit behaviour.
 

SamR

Joined Mar 19, 2019
4,492
One big problem with excessive heat is not only loosening the part but also lifting the trace from the board. Yes, there can be too much heat. The idea with desoldering is to quickly transfer heat to the solder. Which requires a large thermal mass in the tip. In other words, the biggest, chunkiest, tip that you have. I recommend something like this. Larger thermal mass = greater heat transfer faster. And let your iron get good and hot before using! Also copious amounts of flux and paste/gel flux is better (kinda stays in place better). Sometimes liquid flux will dry before you can get to it, especially on a warm board.
1666533533020.png
 

Thread Starter

coolsun67

Joined Oct 22, 2022
10
FYI that is not how we trouble shoot and diagnose a bad system.
We look at functionality, take voltage measurements and look at total and partial circuit behaviour.
MrChips,
If would be so inclined to point me in the right direction that would be awesome. There are components on both sides of the 2 circuit cards. I just got a power supply the other day so I'll be able to make sure power is flowing through some of the components.
 

MrChips

Joined Oct 2, 2009
27,686
MrChips,
If would be so inclined to point me in the right direction that would be awesome. There are components on both sides of the 2 circuit cards. I just got a power supply the other day so I'll be able to make sure power is flowing through some of the components.
I just copied this from another thread:

First thing is you tell us what is the instrument, make and model.
Second thing to do is to locate a circuit drawing.
Third thing to do is to document what you see, hear, smell, feel by touch, history and condition of the unit, what it does and does not do.
Fourth thing, for help on AAC, is to post photographs.
 

Thread Starter

coolsun67

Joined Oct 22, 2022
10
I just copied this from another thread:

First thing is you tell us what is the instrument, make and model.
Second thing to do is to locate a circuit drawing.
Third thing to do is to document what you see, hear, smell, feel by touch, history and condition of the unit, what it does and does not do.
Fourth thing, for help on AAC, is to post photographs.
It's a thermoking precedence expansion module. I'm still working on drawings. Trying to get anything from this company is horrible and I work for them. I have been waiting for a response for over 2 weeks for a different part. I was handed to me and I was told doesn't work. There is no burnt smell to the board.
 

MrSalts

Joined Apr 2, 2020
2,620
It's a thermoking precedence expansion module. I'm still working on drawings. Trying to get anything from this company is horrible and I work for them. I have been waiting for a response for over 2 weeks for a different part. I was handed to me and I was told doesn't work. There is no burnt smell to the board.
Ha, Thermo King used to be a great company with no competitors making money as fast as they could. They used to sponsor a racing team - Tyrone Malone and his Super Boss Kenworth. My dad consulted on the paint job on that truck. AMI had plastic models and Malone sold big brass belt buckles at his events. He was a Master of self promotion and marketing.

eventually, Thermo King stopped sponsoring and the tire retread company, Bandag started sponsoring him (which worked well because he smoked a lot of tires during his shows).

1666560598453.jpeg
 

bassbindevil

Joined Jan 23, 2014
640
What's it costing to have the unit out of service? For a business, it's probably better to buy the replacement, or send the board back for factory repair. Without the factory documentation and test apparatus you can't be sure it's REALLY fixed and operating correctly.
 

Thread Starter

coolsun67

Joined Oct 22, 2022
10
What's it costing to have the unit out of service? For a business, it's probably better to buy the replacement, or send the board back for factory repair. Without the factory documentation and test apparatus you can't be sure it's REALLY fixed and operating correctly.
They already replaced the board. They just want to see if I can fix it for them. They want to have a side business per say. I have already fixed a couple of other boards for them. So it has paid for all the soldering equipment.
 

Thread Starter

coolsun67

Joined Oct 22, 2022
10
In 2008 I went to a school for the military doing circuit card repair. Mainly trace repair and eyelet repair type of stuff. When I got shipped off to Korea for this same job. There wasn't alot of board fixing. I went in the military working on f-16's on the electrical side of things. When I got out I started in the oil and gas industry working on cnc equipment.
 
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