TLE5206 cold solder joint?

[explorien]

I finally assembled my Metal Maslow kit, built my wall-mounted frame, and got ready to calibrate today. I tested the motors/encoders on WebControl before beginning the process, and kept getting a failing left motor result:

Testing L motor:
Direction 1 - Pass
Direction 2- Fail
Testing R motor:
Direction 1 - Pass
Direction 2 - Pass

… and after which, the L motor would spin CCW continuously. I sleuthed around the forums and found a mention of failed left motor tests (Left Motor test fails - #43 by Daniel_Papesca), and a possible cold solder of the driver chip. Sure enough, as suggested by @Jatt, pressing the heat sink of the M3 chip randomly got the CCW spinning to stop. Now the question is: how can we identify the cold solder joint? I snapped a pic of the solder work under my TLE5205 board. I’d like to clean up any other cold joints while I’m at it.

[Jatt]

Generally a cold solder joint will have a dull look to it or have a visible ring that looks like a crack in the solder. A 60x jeweler’s loupe comes in handy if you’re trying to spot them, or you could just reflow all of the joints on that chip, one by one.

[explorien]

Thanks for the tip. I can typically catch cold solder joints when there’s a pin protruding past the board (e.g., when a component’s pin leg is sticking out). I’m having trouble here figuring out where the pins are for the motor driver chips!

[Jatt]

are they surface mount? what does the other side of the board look like?

[explorien]

Oh, duh. I haven’t soldered any surface mount components before. Should the solder at the ends of the chip legs be checked?

[Jatt]

Without surface mount liquid/paste flux, you’re going to have a hard time soldering those, because the solder will try to bridge the gap between the legs. You might be able to reflow with a hot air gun, but it’s 50/50. if you haven’t done it before, you generally dont want to learn on something important. It might be worth contacting @Metalmaslow to see if he’s willing to send you another board, as this one is defective.

[explorien]

Thanks for the tip and all your help so far, @Jatt! I’ll reach out to @metalmaslow. In the meantime, I did try to resolder those legs. It’s not the cleanest, but no legs were bridged (checked with an ohmmeter) and the 3 legs closest to each via are respectively connected. I’m dying to set up my maslow, but I want to be safe and avoid any disasters that might happen due to poor soldering. Is there a way to check that?

[Jatt]

As long as they don’t have continuity to each other, they should be fine to test. Don’t put too much of a load on the chip without a heatsink on it.

[Orob]

Yeah, those soldered pins from the chip should be all uniformly attached to the board. That looks hand soldered to me. Does that chip have a large ground pad on the back side also? If so, I’d make sure that one is down properly., But a quick touch up of those pins should fix you up. What board version is that shield?

[explorien]

The chip pins were very uniformly soldered before I tried to resolder them by hand. There is a large ground pad on the back side. I’ll touch that up too, just in case.

There is a “v1.4” stamped on the board, so I’d assume that’s the version number.

[Metalmaslow]

sorry you are having issues with the board. we can send you a new TLE5206 board. it will look a little different but function the same. we basically switched to through hole components instead of SMD. please send email since I dont know your address based on your forum user name and also dont’ check this forum every day.

[explorien]

Thank you @metalmaslow! I just emailed you. I really appreciate your support. Can’t wait to get up and running with your kit!