Looking for constructive criticism

[z-adamson]

First time desoldering and resoldering a pc board. This is a crossover board from a realistic mach 2.

Does my soldering look good?

Do the caps look secure?

Do you see anything that does not look right?

Thanks!

 

[RocketMonkey]

Too much solder, if the wetting isnt concave you have to much solder. A lot of people use solder that is too heavy guage to control easily. Its kinda grainy but I see flux on the board still. Also strain relief bends are wise with big axial lead components.

 

[RocketMonkey]

Wetting looks solid though and that is the most important part.

 

[z-adamson]

It does look less rough in person.

What do you mean by too much solder? I can see how it is a little more than needed, but do you mean to imply that the amount of solder present is detrimental to the functionality of the crossover?

 

[z-adamson]

Strain releif bends? How would I implement this?

 

[RocketMonkey]

So about the solder, it wont hurt anything in an audio circuit, just the way I was trained. With a round nose pair of pliers bend the lead. I'll try and find a picture to describe it.

 

[RocketMonkey]

 

[RocketMonkey]

 

[RocketMonkey]

With the strain relieving the key is don't bend the part at the component body. So hold the pliers near the body and then bend the lead around the pliers to form the desired bend.

 

[nedseg]

Great tips. Pretty good job, agree with Rocket. Hard for me to tell for sure, but are those leads sticking out from the solder? Use good flush or side cutters to trim them down closer to the solder...pity the poor QC tech who gets poked & scraped by those things.
Keep up the practice, you're on the right path...now do thousands of 'em

 

[RocketMonkey]

Yeah technically it would be a fail for leads sticking out the back too far (3/32s or two times the wire width whichever is less), leads on the back crossing over to another trace, lead strain relief and residue. So to keep it constructive its wise to bend the leads so that they follow or at least don't stick out past the trace they are connected to. But for amateur audio this is mostly nit picking. Dressing the leads better will look nicer and be less likely to cause a short so I'd say that would be worth the effort. Strain relief will reduce the odds of a lead braking but yet again I don't think anyone will die if your crossover fails. Certainly better than some "professionals" I've seen.

 

[z-adamson]

That smudge to the left of center is not solder flux splatter. It's just a "smudge" grom touching it and it really stuck out in the pic from the flash.

Yes there is a tiny bit of lead hanging out past the solder. I did all the soldering before I cut the leads. After soldering I trimmed the leads as short as seemed practical.

I will address the strain releif. Will I gain anything by reducing the amount of lead hanging past the solder?

What do you mean by " leads on the back crossing to another trace"?

Thanks guys!

 

[loudnoises]

That smudge to the left of center is not solder flux splatter. It's just a "smudge" grom touching it and it really stuck out in the pic from the flash.

Yes there is a tiny bit of lead hanging out past the solder. I did all the soldering before I cut the leads. After soldering I trimmed the leads as short as seemed practical.

I will address the strain releif. Will I gain anything by reducing the amount of lead hanging past the solder?

What do you mean by " leads on the back crossing to another trace"?

Thanks guys!

if you look at the joints on the back, the extra leads sticking out of the solder are long enough to be bent back down and make contact with adjacent traces. Is bad, but trimming them close solves that issue.
I was always taught the solder should be concave between the lead and board, looking more like a trumpet end. But it takes practice and you'll be just fine with those joints IMHO.

But yeah trim leads, shorts are bad.

 

[RocketMonkey]

By your thumb in the picture, that lead (in RF thats an antenna and at any speed its easily made into a short by pressing and vibration. The solder mask is the only isolation between conductors.). It hangs over a different trace than what it is soldered to. Also I would not rework this just to fix strain relief. Probably will never break and more bending increases the odds of a lead breaking. Im just being pickey because you asked for constuctive criticism. Anything I see that isn't the way I've been tought to do it I'll suggest a correction. If you keep on with soldering get some flush cutters. They make it easy to cut the leads down super short. Good tools clean iron tip and clean contacts go a long way. Dwell time with the iron tip should be 3 seconds or less (It will be longer sometimes if you don't have a billy bad ass iron). If it takes longer than than something is not right but that doesn't mean it won't work. Most of the rules are for reliability and ease of inspection so much of it will not affect performance of an audio circuit. One more thing I should mention, the solder should not make the connection. The parts should be in firm contact (as much as possible) with each other just with the tension of the leads. Then the solder fills the spaces between. This is why you bend them flat after they go through the board. You are maximizing that contact.

Buy a kit or somethig like this to practice on.
http://www.elenco.com/product/produ...MTA2/1mhz_function_generator_in_kit_form=MjEx

These elenco kits have good instructions. The soldering image came out of one. Its fun but can be very tedious if you want it to look perfect. Working on consumer audio equipment at home is liberating, its your choice how picky you get.

 

[z-adamson]

Great feedback guys, just what I needed to further the quality of my work.

 

[RocketMonkey]

If you feel the urge to go nuts sleeve the leads in teflon tubing.

 

[BinaryMike]

Strain relief will reduce the odds of a lead braking but yet again I don't think anyone will die if your crossover fails.

The purpose of strain relief is to reduce stress on internal structures of the component. Stress transmitted through the leads of through-hole components can eventually loosen internal connections or break the package seal and allow environmental contamination to degrade the part. In a speaker crossover network, the bodies of all components must have absolutely secure mechanical attachment for two reasons: to prevent lead breakage via metal fatigue and to prevent rattling. Sound pressure inside the enclosure can reach astonishing levels.

 

[RocketMonkey]

Iv never seen a metal film capacitor break inside from vibrations but I've seen broken seals where the leads were bent near the case. If Z feels the need to rework it so be it. I was under the impression RTV and potting was for vibrations and lead strain was for thermal expansion.