Few questions from a beginner

[Gianni]

Re: Few questions from a beginner

I use the same method (solder sucker) of ratdude747 for PSUs because they are single layer.
For MOBO I use solder sucker and sewing needle, I learnt to use it reading on Badcaps.
When I can, I bring stuff in office where I can use a desolder station, much better than solder sucker. Unfortunately they are expensive and for the amount of work I do at home I really don't need one.

About using solder sucker when I have to free an hole on a MOBO I heat the hole with the solder on one side and I remove the solder with the solder sucker from the opposite side. Usually it works but on some holes I have to use the sewing needle because I'm not able to remove completely the solder with solder sucker.

Willawake is right about solder debris but cleaning very often the solder sucker reduce the risk.

Ciao
Gianni

[Krankshaft]

Re: Few questions from a beginner

I use the standard conical tip on my dash place the braid over the hole place the tip into the hole apply light pressure for a few seconds and most of the time the hole is then clear. I remove the braid when I don't see it sucking up any more solder.

Single layers don't require this kind of attention.

If that doesn't work (and one of the caps holes is clear) I place the replacement caps lead on top of the hole (apply light pressure to the lead) and again put the tip into the hole on the solder side and the lead usually pierces through when the solder melts.

There usually is so little solder plugging the hole the cap then moves freely even after removing the iron.

If the above doesn't work and it rarely doesn't I use the last resort the needle method.

[chaosoffar]

Re: Few questions from a beginner

Well looks like I've procrastinated long enough. Still have a few questions:

1. What size wick is recommended?
2. Lookin at a chisel tip; 1/32,1/16,1/8, or 3/64"?
3. What's the recommended way to test a power supply after replacing the caps?

[PCBONEZ]

Re: Few questions from a beginner

Soldering is kind of a style thing.
You have to experiment with it until you find what works for you.

1. What size wick is recommended?

Start with 2.54mm and adjust from there until you find your sweet spot.
Remember to loosen the braid a little if it pulls tight when you pull it out of the dispenser.
If the braid is too tight the solder can't get between the strands as easily.
Too loose and the wicking action won't be as good.
- Play with it.

2. Lookin at a chisel tip; 1/32,1/16,1/8, or 3/64"?

A small assortment is better. Most of mine are 1.5mm to 3mm.
If you are going with one tip then get one around 2.0-2.5mm. [Or rather I would.]
Experiment and see what works for you.
-
What you don't want is a long thin taper.
Fat tips with short tapers hold the heat better simply because they have more mass behind them.

3. What's the recommended way to test a power supply after replacing the caps?

First use one of those cheap PSU testers to make sure it doesn't outright explode.
Let it sit on that for maybe 1/2 hour to burn in the caps.
Check volts.
Connect to cheap mobo, load it, check volts again.
If you have an O'scope to check the ripple when you check the volts that's better.
.

[etnietering]

Re: Few questions from a beginner

Something else you can do for testing, if you don't have a PSU tester: attach it to an old hard drive or two, and some fans. If you're like me, you have lots of these lying around...
It won't load things much, and won't load the 3.3v line at all, but it's something you can do if you don't have a PSU tester.
Make sure you don't really care about the hard drives and fans...and stay by it for the first minute or so, in case you hear a pop or a BANG.

Also, if you're like me and have lots of random electronics sitting around, you can ghetto-rig a power resistor (5-10 ohms would work fine) into the orange wires on the ATX connector to load the 3.3v line.

[larrymoencurly]

Re: Few questions from a beginner

Well looks like I've procrastinated long enough. Still have a few questions:

1. What size wick is recommended?
2. Lookin at a chisel tip; 1/32,1/16,1/8, or 3/64"?
3. What's the recommended way to test a power supply after replacing the caps?

1. I'd use up to 1/8" wide braid for a single-sided PSU circuit board. I once tried 1/4", but it absorbed so much heat that my 40W iron couldn't keep up with it. BTW it helps a lot to cut off any used braid right away, even if it hasn't absorbed any solder (heat destroys the flux, but applying new rosin flux helps), because dangling braid just takes heat away from the joint.

2. 1/8" is good, 1/16" is probably a bit too narrow, except maybe for IC pins. I recently quit using a sponge to clean off the tip because it seemed to actually put old rosin back on the tip. A damp paper towel or that curly copper or brass hair for cleaning pots and pans seem to work a lot better.

3. With its cover put back and completely screwed on, to protect against electric shock and any exploding capacitor. In once ran a PSU like an Antec SmartPower without the cover, and I foolishly plugged the AC cord first into the wall outlet and then into the PSU. Without the cover installed, that made the PSU case flex enough to short against one of the heatsinks, which had 170 volts DC riding on it, causing a spark and the PSU to shut down. At first I thought I had blown the rectifier or the high voltage transistors, but the PSU worked fine when I turned it on again. The only thing I did right was plug the AC cord into a ground fault interrupter for shock protection (experts recommend an isolation transformer as well).

I've recapped my 300W, 350W, and 500W Antec SmartPowers. Kind of crowded with the 12.5mm diameter caps in place of the original 10mm ones, but I managed, as others have.

[c_hegge]

Re: Few questions from a beginner

First use one of those cheap PSU testers to make sure it doesn't outright explode.
Let it sit on that for maybe 1/2 hour to burn in the caps.

You can't leave a PSU on a tester for more than ~ 2 minutes. They are cheap and inadequately cooled. I left a PSU on a tester for ~ 10 minutes and the tester melted.

For replacement caps I have used Chemi-Con KZE, Panny FC and FM, and Nichicon HE. All of them seem to work fine, other than the larger diameter.

[PCBONEZ]

Re: Few questions from a beginner

You can't leave a PSU on a tester for more than ~ 2 minutes. They are cheap and inadequately cooled. I left a PSU on a tester for ~ 10 minutes and the tester melted.

I only have two because they've never broke.
That hasn't been a problem with either of them because they don't pull enough current to get hot.
Quite possible there are some out there that are so poorly designed that they'll melt but neither of mine have.
I've left them go over an hour at times to reform NOS caps in PSUs.
.

[PCBONEZ]

Re: Few questions from a beginner

larrymoencurly touched on something rather important that I missed.
You want braid with flux in it, not the dry braid.
It works ~way~ better with the flux.
.

[370forlife]

Re: Few questions from a beginner

Long ago I used one of those cheap coolmax psu testers to run a psu to run some fans pulling air into my room overnight. I woke up about 30 minutes later to a pop and the smell of burnt electronics.

The old rosewill/deer was fine, but the coolmax 'sploded. Just used a paperclip next time, no problem there.

[PCBONEZ]

Re: Few questions from a beginner

Did you look at what popped?