Introduction to DIY Questions and Cmoy Contruction

[chiefroastbeef]

Does flux help in preventing cold solder?

 

[deltaydeltax]

Quote:

Originally Posted by chiefroastbeef /img/forum/go_quote.gif Does flux help in preventing cold solder?

Definitely.

I can see it helping even more so when using a non-plated board such as the ones pictured in this post. That exposed copper just oxidizes as it sits on store shelves and becomes more and more difficult to solder to.

When I used to use these smaller boards to build stuff, I cleaned them first with a pencil eraser the best I was able to, then plated them with a chemical like this:
Liquid tin

Also cleaning your boards after you solder helps avoid bridges created by 'solder infused' flux.

 

[chews89]

Ok, I think I'm using the multimeter correctly but I'm still not getting any reading.

Do you think cleaning the board with pure isopropyl alcohol will help? Or will it just be a waste of time? What else could i try? Should I use desoldering braid to try and get rid of the excess solder?

 

[chiefroastbeef]

Thanks for the input!

I didn't use flux(although I had a tub) on my mini3 or alien because the solder I have already has flux. Well at least the board is plenty messy after I finished. Alcohol worked great in cleaning it up, I mean, the flux wouldn't even budge with my finger nail scratching!

 

[chews89]

Ok I've cleaned it with alcohol and reflowed the solder a bit but I still get a reading of zero. But what does this zero mean? Either I'm totally using the multimeter wrongly or i placed the capacitors in the wrong orientation?

But I'm pretty sure I did both correctly.

Any further input would be Greatly appreciated.

 

[Fred_fred2004]

You should be measuring from the two central copper strips (which is virtual ground) to the red and black wires. Your Meter should be on DC volts. If all else fails measure the battery voltage to confirm you have the meter set for reading voltage

 

[chews89]

So it turns out I wasn't getting any readings because my leads weren't plugged into my multimeter correctly :\ How stupid of me..

Anyway, I'm up to the part where i solder in the capacitors. But thing is I don't get what this part of the diagram means:

So I know I'm meant to solder where the "X"'s are but what is that black line coming out to the left? Am I meant to add a jumper there or something? Also, instead of the two R5's, I can just add jumpers in their places?

 

[deltaydeltax]

Quote:

Originally Posted by chews89 /img/forum/go_quote.gif So it turns out I wasn't getting any readings because my leads weren't plugged into my multimeter correctly :\ How stupid of me.. Anyway, I'm up to the part where i solder in the capacitors. But thing is I don't get what this part of the diagram means: So I know I'm meant to solder where the "X"'s are but what is that black line coming out to the left? Am I meant to add a jumper there or something? Also, instead of the two R5's, I can just add jumpers in their places?

You're not stupid, you're learning. We've all been there. I still have a scar on my leg from soldering in shorts 17 years ago. That was the last time I did that.

I think those 'x's are just showing the locations of the parts pins. Inside that yellow box you created, you'll just have a jumper going over to the land where you'll solder your input wire (no jumper wire is needed if the part lead can reach the land) . That is the wire you'll connect the positive of your input to.

Looks like you're almost there.

 

[chews89]

Oh ok, so just to clarify, I can go ahead and solder the capacitor leg into the hole in the yellow box which is on the left of the "x"?

 

[chews89]

Ok, I've put everything in now, but when i apply power to the board, my op-amp gets warms up. Is this quite normal or do I have a problem?

 

[Fred_fred2004]

You may have a problem, any sound?

 

[SiBurning]

You've gone beyond the picture in post 29, so it might be worth posting a new picture. The picture in post 29 has some suspicious looking joints. The third and fourth lands on the left (Datek) side look like they might have a solder bridge. On the right (CIC) side the red wire soldered to the second trace looks like it's touching the third trace. Get a magnifying glass and inspect everything visually. Be really careful to look at stranded wires. Then double check that everything's as you want it. Also, that middle hole under the Datak looks cold. The hole next to it looks like it has rosin connecting it to the center track--scrape the rosin with a sharp pointed thing to get a clear space between them. Sometimes what looks like rosin can hide problems. It's all kind of hard to tell from a photo. It can also be hard to tell under 3X magnification. Good quality 10X optics and bright light is the best way to inspect. A jeweler's loupe is a good way to get good quality optics cheap because the lenses are so small.

 

[chews89]

I've used Tangent's guide and hooked up the circuit to my source and headphones, and the sound is very dodgy. The sound seems tiny with crackling and hissing. If i adjust the alligator clips now and then i get some good sound but nothing constant. Here's what I have so far:

Edit: Yes now i see a cold joint on the bottom left. But I don' think it's important because it's only a test point to test the amp.

 

[Fred_fred2004]

You've got a solder bridge between pins 7&8 and a possible between 6&7

 

[chews89]

Pardon my noobness, but where exactly is that? I don't know how to refer to the pin locations by number. Sorry

Edit: Ok so i used a knife to cut away what i thought were solder bridges and there's sound! It actually sounds quite good but the thing is, whenever i connect the ground wire from my headphones to the ground on the board, the music distorts, but when i take it off, the music is fine. Any ideas?