Crack resistence check, getting above 0 ohms on terminal 6 and 8

[hockeygreen2]

Hi! First time building a kit like this. Assembled it a few days ago, passed the resistance check and voltage check. The amp worked and sounded really great, there was some electronic noise that I noticed that I assumed was due to a few sloppy soldering joints on my part, I tried to fix them up but now I can only get sound out of the left channel, there is no sound out of the right. I went back to basics and re-did the resistance check, all the terminals measure fine except for 6 and 8 which measure above zero ohms now. 6 measures essentially as infinity and 8 measures as 2.9 which I though was extremely strange. In addition to that the second led on a8 does not light up anymore. I've tried re flowing joints, adding solder, taking away solder with my desoldering pump, I've been doing this for the past two days with no luck, needless to say I'm completely stumped. If you guys can help me out I would greatly appreciate it. Let me know if there is any more info, pics, and measurements that you might need to help me figure this out.
Thanks!

[Paul Birkeland]

Can you post some photos of your build?

Terminals 6 and 10 should have 0 ohms with no headphones plugged in.  If you don't see that, the immediate suspect is the joint on the headphone jack where the black wires meet.

The LED not lighting up on the socket is often a loose joint that has nothing to do with the LED itself.  If you attempt to resolder the LED repeatedly, you'll damage the LED.  Can you post your voltages on terminals 1-10? (after checking the above mentioned solder joint)

[hockeygreen2]

Hello! So bad news, when I measured the voltage of terminal 3 there was a big pop and some sparks flew. I tried re soldering the jack where the two black wires meet. Here are some photos of the build.

[hockeygreen2]

Here's some more photos.

[hockeygreen2]

One more! Sorry for the spam but I'm having some connectivity issues with the forum, doesn't seem to be letting me put all the photos in one post.

[Paul Birkeland]

There are on or more issues at work here.

1.  You definitely need some proper side cutters.  CHP-170 cutters are inexpensive and do the job well, and this will let you trim your leads back considerably.
2.  Possibly your iron isn't hot enough to properly flow your solder and/or
3.  You're using lead free solder.

Notice that none of this really has anything to do with skill level or experience, so rest assured that some adjustments to tools and temperature settings are likely all that's needed (and maybe a new LED or two).

[hockeygreen2]

Hi! So I definitely used lead-free solder for the build. I just ordered some leaded rosin core solder which should be here in a couple of days. I think my plan right now is to try and clean up the board as much as a can with the new solder when it gets here. Fingers crossed the new solder helps solve the issues, once I do this I'll message again if it still does not work. Thanks so much for your help! I hope that the leaded solder will help fix most of these issues!

[Doc B.]

We do have a soldering primer now, that might be helpful -

[Paul Birkeland]

You're going to be shocked at how much easier leaded solder is to work with.

[hockeygreen2]

Hi! Just got the leaded solder today! You're right it is so much easier to work with. I've resoldered most of the problem connections, and now both terminal 6 and 9 are measuring as 2.9 which is still not right but its different then it was before. just wondering if there is any more connections that you would think still need to be resoldered

[Paul Birkeland]

Just to be clear, terminals 7 and 9 should measure about 3K.  Are you absolutely certain that terminal 6 measures 2.9K? 

If terminal

[hockeygreen2]

Yes. I've measured 6 a few times and it measures at 2.4 now

[Paul Birkeland]

OK, 2.4 means that you have probably overheated the jack to the point that the plastic has melted and the contacts have moved.  This would not be that surprising knowing that you used lead free solder, since that stuff is so resistant to flowing in the first place that it takes a ton of heat to get satisfactory results.  I would definitely replace the HP jack.

[hockeygreen2]

Okay that makes a lot of sense, the headphone jack does look like it's in bad shape, any ideas on where I could get a replacement?

[Paul Birkeland]

What country are you in?  It would probably be easiest for me to find you one from a retailer near you to avoid international shipping.

-PB