Prime95, V28.10 Build1 x64, Lockup Stopping workers

[chalsall]

Originally Posted by dkemppai

Just tried to scope the Vcore voltage, and one of the inductors for the VRM had a bad solder joint on it! It looks like it never flowed, or flowed poorly and melted later. More testing to be done now that it's reflowed.

Just to share, I find that most people don't know how to solder correctly. It doesn't matter if it's a circuit board and components, or a copper pipe.

Most people melt the solder with the iron, and expect it to affix to the metals to be connected.

Instead what should be done is to carefully heat the metals to be affixed, and let the solder melt.

Long ago we used to hold "soldering parties" for small production runs, experienced guys coming around to solder for beer and pizza. One guy was so good that he could solder in a 40 pin strip in about two seconds.

He would run the soldering iron between the PCB and the component, and then closely follow with the solder. Then he would take a bite of his pizza, take a swig of beer, and then repeat.

[dkemppai]

Originally Posted by chalsall

Just to share, I find that most people don't know how to solder correctly. It doesn't matter if it's a circuit board and components, or a copper pipe.

In this case, a little liquid RMA flux, good temp on a very large tip was needed. Flow took a while, so there are probably large copper pours and this is probably built on heavy copper also. Once it flowed I added a little more solder, and it looks as good as the rest of the joints.

So, it's been running steady now, at 4.9Ghz with less voltage than needed previously at 4.8Ghz. So far start/stop Prime95 has been without trouble since the solder joint.

More testing to see how it holds out!

Thanks,
Dan

[chalsall]

Originally Posted by dkemppai

In this case, a little liquid RMA flux, good temp on a very large tip was needed.

Yeah, flux is important; helps with the "wetting". Thank you for reminding me of that.

Edit: I do find it a little odd that LaurV hasn't yet spoken on this topic. He regularly works on surface mount stuff.

[dkemppai]

Originally Posted by chalsall

...He regularly works on surface mount stuff.

It's been solid so far. Lost an old platter drive in it today, but that was an old junker just for scratch space...

Yeah, my day job is designing and build of analog, RF, digital, and power circuits. Part of my job description is to instruct people on soldering technique, and inspecting their work. We use a lot of SMT components, although we still try to avoid flip chip type and BGA packages as inspection is too difficult. Some of the bigger boards we've done are close over 1000 components, with a good mix of multi Ghz stuff, and associated passives. We're just starting to play with some 2 to 3 Gbit/second serial link stuff too. There's probably close to 100 different types of solders, some better for specialty applications than others...

I still find it hard to believe that this board had a cold solder on it. Although, that may explain why I picked the whole thing up so cheap. Wasn't really shopping for a FX-9590 system, but it was offered at a price I couldn't refuse.

Just goes to show, Prime95 stress test can point out problems that 99.99% of the time will never show up... :)

Thanks,
Dan