Best Soldering Helping Hands

[moamps]

For the article you posted I disagree with the phrase "must"...

I agree with you on this. We don't agree on the rest, so I suggest we stop there.

Is that why the old Neve cards sound better?

It certainly works more reliably and maybe a little better.

 

[scott2000]

It may be justified if there is no other way of retaining components in place when the PCB is turned over, which seems amateurish to me.
Most DIYers (should) have a foam gizmo for preventing components to fall off

foam gizmo does have a less amateurish ring to it....

I can see my wife asking wtf when I'm using the mattress topper as a workstation to speed things up....lol

 

[sahib]

I dug around the workshop today and as it happened I had a Soundcraft power amp board. I have also been trying to fix my Hameg function generator, but as Hameg refused to supply the schematics and asked for a repair fee considerably more than the market value of the machine, I had it enough and decided to part it all out. So, I have a pretty good case example there too.

Below is from a Soundcraft power amp. The resistor leads are bent. Have a look at the pad size and come to your own conclusion what electrical or mechanical benefit can exist by bending the lead in that size of pad area. May be in radio frequencies? I do not think so. I will come to that later on.

However, as I mentioned before, for speed of assembly it makes sense and in this case since there is generous component spacing it is reasonable to think that it is safe. But see the areas circled in yellow. See how close the leads are, particularly in the first circle. And try that in a densely populated board. Major risk.



The below picture is from the same board. Power resistor and its solder node. It is not bent. So, if there was a gain to be made from mechanical strength and heat dissipation point of view, this is where you want the lead bending to be. So the argument again does not hold.



Next pictures below are from my now RIP Hameg. The entire board is through hole components and leads soldered straight.

The picture on the left is the output stage where the BNC is connected to the board through the yellow wire at the bottom of the picture. The picture on the right show the solder side. Now, again if there was any electrical benefit such as reduction in resistance due to long component lead from bending, this is where you want it to be the most. That area handles 10MHz. The people who design these equipment surely know a thing or two. But they chose not to, because longer the lead greater the inductance and you certainly do not want anything like that here. So, again there is no electrical benefit in bending.



In summary, bending the leads provides speed of assembly where it is safe to do so. But that's all. The claim that it must be done that way, or it is the correct way of doing it is not correct. I also argue against the claim that it provides superior electrical performance. There is no evidence of that.

 

[abbey road d enfer]

Next pictures below are from my now RIP Hameg. The entire board is through hole components and leads soldered straight.

Probably designed by heathens...
This whole issue seems to be dominated by belief and tradition.

 

[moamps]

The below picture is from the same board. Power resistor and its solder node. It is not bent. So, if there was a gain to be made from mechanical strength and heat dissipation point of view, this is where you want the lead bending to be. So the argument again does not hold.

View attachment 95099

Next pictures below are from my now RIP Hameg. The entire board is through hole components and leads soldered straight.

This PCB shows you how all the other joints are perfect and these two of these high power resistors are suspicious because you can see the dark part of the lead where maybe there is no good connection of the solder and the lead (cold joint).

The picture on the left is the output stage where the BNC is connected to the board through the yellow wire at the bottom of the picture. The picture on the right show the solder side. Now, again if there was any electrical benefit such as reduction in resistance due to long component lead from bending, this is where you want it to be the most. That area handles 10MHz. The people who design these equipment surely know a thing or two. But they chose not to, because longer the lead greater the inductance and you certainly do not want anything like that here. So, again there is no electrical benefit in bending.

View attachment 95100

Maybe your Hameg died because of bad soldering. I never liked Hameg.
Here is a picture of a board (test receiver - messempfanger) by Rohde Schwarz, so judge for yourself.

In summary, bending the leads provides speed of assembly where it is safe to do so. But that's all. The claim that it must be done that way, or it is the correct way of doing it is not correct.

I didn't said that.

I also argue against the claim that it provides superior electrical performance. There is no evidence of that.

I said better performance, which is often not crucial, especially in a DIY environment.

I don't want to argue with you about this anymore, I'm quite happy that we've evolved from the idea that bending is extremely bad to the fact that many use it and that maybe this method is better than leaving the leads straight.

 

[sahib]

This PCB shows you how all the other joints are perfect and these two of these high power resistors are suspicious because you can see the dark part of the lead where maybe there is no good connection of the solder and the lead (cold joint).

I can confirm that all power resistor pad areas are perfect and there is no baking.

Maybe your Hameg died because of bad soldering. I never liked Hameg.
Here is a picture of a board (test receiver - messempfanger) by Rohde Schwarz, so judge for yourself.

The soldering on my Hameg is like crown jewels.



I love Hameg. I had my first Hameg oscilloscope in 1978 from new (which I think had a bandwidth of 100MHz as it was long time ago). A beautiful machine it was, with phosphorus screen acting as hold so that you would have enough time to photograph the captured waveform. I did not know how to use it properly though as I was only 17 at the time and new to electronics.

However, I do not understand what am I supposed to judge. Are you saying the boards with bent leads do not fail?

I said better performance, which is often not crucial, especially in a DIY environment.

That is the bit that I am trying to understand. What better performance can be obtained from bent leads. As well as my practical experience, I have a sound knowledge of electrical fundamentals and good math skills and I am still failing to see what the performance benefit can be. But I am open to learning and that is one of the reasons I hang around this forum.

I don't want to argue with you about this anymore, I'm quite happy that we've evolved from the idea that bending is extremely bad to the fact that many use it and that maybe this method is better than leaving the leads straight.

I do not mean to create an argument but to discuss what performance benefits it can have as you still claim , and you are failing to explain that. I also do not mean to patronise but you are one of the technically sound people on this forum.

However, I'll agree to disagree and bow out too.

 

[moamps]

......but to discuss what performance benefits it can have as you still claim , and you are failing to explain that..

Your only argument why the leads are bent is the higher speed of assembly, which is not very clear because in this way a new process is introduced, bending the leads. I would even argue that it is quite the opposite. Higher mounting speed is obtained by not bending the leads.
In addition, the PCB may contain components that do not have bent terminals (ICs, terminals, etc.), so that some kind of system for retaining the components on the board during the soldering must be installed anyway. Also, I do not believe that companies like R&S or Siemens would want to save some time and money because what they produced is not a mass-produced product and price was not an issue.

I explained my arguments, and gave examples. You took two PCBs and based on one faulty device and one device where it is still evident that the solder did not catch properly to lead




you refuted my arguments. Yes, I obviously failed to explain it to you, most likely because you just don’t want to hear it.

 

[sahib]

Moamps,

I have huge respect for you but you are picking on the shadows to make something out of it. I have already confirmed that the solder nodes are fine and with no baking. I can re-photograph but I will not do.

 

[scott2000]

So what's the recommended method/tool to hold a th resistor in place when having to replace a couple of sets nestled pretty snug in between a bunch of components? I did fine removing and inserting them (yes the previous bent leads made it not fun) but, one set I guess slid slightly up off of the board when trying to solder them because I couldn't hold get anything in between to hold them, and now I can't push them back down. actually tweaked the excess leads on the board side looking goofy now.....Fingers can't take it no more..

 

[abbey road d enfer]

So what's the recommended method/tool to hold a th resistor in place when having to replace a couple of sets nestled pretty snug in between a bunch of components? I did fine removing and inserting them (yes the previous bent leads made it not fun) but, one set I guess slid slightly up off of the board when trying to solder them because I couldn't hold get anything in between to hold them, and now I can't push them back down. actually tweaked the excess leads on the board side looking goofy now.....Fingers can't take it no more..

Adhesive tape?

 

[scott2000]

Ah ..of course..

 

[sahib]

Indeed as Abbey said masking tape is a good tool as it has low tack. But avoid strong tapes like gaffa (or gaffer) or packaging tapes. Hell, stay away from things like Gorilla Tape.

In case the tape leaves residue, wipe it off using alcohol. There used to be 3M Clean Art which was essentially a purer version of cigarette lighter fluid, but after the factory burned down (I think in France) some years ago they stopped manufacturing it. So, cigarette lighter fluid is also good for wiping off residue. But go easy on it.

I use these sponges.



Wet it lightly, insert the resistors into your board, sandwich them with the sponge, turn it over and lay it on the table and solder. The sponge will not only lock the resistors but also help dissipate the heat.

I do not insert all of the resistors and solder them at once if the board is very densely populated (which is the case with our products).

I also solder one value at a time, particularly if I am assembling a batch of boards. The resistors (and everything elses) are stored in individual drawers. So, I take one value/drawer, solder all the of boards, then move onto the next value.

I used to have eagle eyes (due to modelmaking) when I was younger but not anymore. Worse, I now have advanced glaucoma. So, I use (as well as my glasses) a hand held magnifier for checking the solder nodes as I go along. So, even if you have good eye sight, use a magnifier of some sort and check your solder nodes as you go along. I occassionally get to repair kits as vast majority of DIYers are good and I also solve the problems over e-mail. But for the ones who have trouble, it always turns out to be a short due to lead bending or solder bridge. I will not give names, but in one occasion I told the user to check the solder nodes for a short using a magnifier and he kept saying they were all good. After over 50 e-mails it turned out to be guess what.

 

[abbey road d enfer]

I used to have eagle eyes (due to modelmaking) when I was younger but not anymore. Worse, I now have advanced glaucoma. So, I use (as well as my glasses) a hand held magnifier for checking the solder nodes as I go along. So, even if you have good eye sight, use a magnifier of some sort and check your solder nodes as you go along.

This is one of the most important tools on my bench.

 

[sahib]

Excellent Abbey.

A forum member and a good friend also gave me a table mount video camera that plugs straight into the computer monitor. I use it for inspecting bear PCBs. I can zoom in and out and it is a great tool.

 

[abbey road d enfer]

Excellent Abbey.

A forum member and a good friend also gave me a table mount video camera that plugs straight into the computer monitor. I use it for inspecting bear PCBs. I can zoom in and out and it is a great tool.

I need to ckeck that.
I have a USB microscope; which I almost never use because I can't see the forest for the trees. A single pad takes about half of the screen.

 

[sahib]

I have not had any of those microscopes but I would imagine they would indeed be too strong.

I'll photograph the one I have tomorrow and post the image. I'll also look up the model. I am sure you can get one second hand.

 

[Newmarket]

I dug around the workshop today and as it happened I had a Soundcraft power amp board. I have also been trying to fix my Hameg function generator, but as Hameg refused to supply the schematics and asked for a repair fee considerably more than the market value of the machine, I

View attachment 95098

The below picture is from the same board. Power resistor and its solder node. It is not bent. So, if there was a gain to be made from mechanical strength and heat dissipation point of view, this is where you want the lead bending to be. So the argument again does not hold.


View attachment 95099

You probably don't want a bend in those power resistor legs.
The legs on that resistor type tend to be quite thick. Bending them is likely to introduce stress or fracture internal to the component. Additionally, they often come with short legs (that may not even need trimming after soldering depending on clearance to adjacent chassis / pcb etc.
This makes bending difficult if not impossible - in reality it becomes more an issue of pushing the leg into a bend rather than 'bending'.
Yes - they will 'desolder themselves' if there's a fault that causes massive overheating and , if on a vertically orientated pcb, fall out. I'll spare people the anecdote but will add that it wasn't my design ! But tbh that was probably preferable to having it make a dodgy connection and sort of working but not properly. When you take the covers off and the resistor is on the deck then it's a lot easier to diagnose.

While I'm here - a few other points that seem to be missing or not properly considered here :
A lot of TH boards will have been made using varying degrees of component placement automation and often followed by wave soldering rather than manual soldering.
Automatic component placement may not facilitate leg bending.
And if the component legs are subsequently trimmed by 'machine' then the actual result is very dependent on the detail of that.

When I worked somewhere where we did some pcb assembly for DDA, there was some comment that the results were preferred due to the close (manual) cropping of leads after a wave solder process. Compared to other CEMs where the cropping was by machine. But it wasn't really edeliberate on our part - we simply didn't have a 'cropping machine'

And where mechanical stability is an issue then deliberate mechanical solutions may be preferred eg the 'kinked' legs common on larger electrolytic capacitors. And there's always the glue/mastic/gunk solution (although I have a personal aesthetic aversion to it).
For connectors 'Press Fit' is a good option although you need to be set up for it - so not really a 'DIY' option. And it seems more of a European rather than a North American / UK thing.

 

[Newmarket]

I need to ckeck that.
I have a USB microscope; which I almost never use because I can't see the forest for the trees. A single pad takes about half of the screen.

Yeah - I have an inexpensive 'Maplin' one. It can be useful but the 'variable' magnification thing seems to be a matter of moving the microscope or the object
One thing to be aware of in general is that when you go 'close in' then even a good board / joint looks a bit rubbish. First saw this some years ago at a trade exhibition. You have to look past all the dust and debris that shows up.
A bit like a typical Bass Guitar DI track

 

[abbey road d enfer]

Yeah - I have an inexpensive 'Maplin' one. It can be useful but the 'variable' magnification thing seems to be a matter of moving the microscope or the object
One thing to be aware of in general is that when you go 'close in' then even a good board / joint looks a bit rubbish. First saw this some years ago at a trade exhibition. You have to look past all the dust and debris that shows up.

I have a USB endoscope too. It seems to give the right magnification but does notr have a stand.

A bit like a typical Bass Guitar DI track

Wait till you hear fretless bass track.

 

[Newmarket]

I have a USB endoscope too. It seems to give the right magnification but does notr have a stand.

Oh the stand is the real weak point. I actually picked it up from a former employer when it went 'down the tubes' (not an audio concern so will bypass details unless anyone expresses an interest in metals analysis Instrumentation !). Anyway - colleagues had already tried to address the issue of slippage by using masking tape but not really working. Seems crazy/laughable when the basic optical technology works well enough to be usable but the product weak point is a nylon/plastic gear thing that isn't strong enough to defy gravity - like a cheap microphone stand !

Wait till you hear fretless bass track.

Yeah - but at least any rattle is metal on wood rather than metal on metal, But I guess tuning issues.
Actually I have one (a fretless bass) but I need to sort the nut out to make it playable.