Photo devices repairs: Soldering and desoldering

[Andreas Thaler]

Soldering is not always easy


The question arose as to how to do good soldering during repairs of photo devices like cameras or motor drives.

It might be a topic that always concerns you, even if you already have practice.


Soldering in tight spaces

With photographic equipment there is the additional challenge of working in a confined space, with cables and components packed tightly together. Here you have to be careful with the hot soldering tip.


The right solder?

Older photographic devices, up until the early 2000s, still used solder containing lead, which is now no longer used in the industrial sector, at least in Europe. It is still approved there for repairs and in private areas. One rule says that you should not mix leaded and lead-free solder, as both have different processing temperatures and there are incompatibilities. I haven't found any problems here. But opinions differ.


Different techniques

And then there are different techniques for soldering, depending on which components are to be soldered. In more modern cameras there are usually ICs and components that are soldered to the surface of the circuit board (SMD, surface mounted device). There are also cables that are connected to the circuit board and components across the camera.


Guidance and tricks

Everyone solders differently, everyone has their own experiences, so I wonder whether we should collect examples here that will give others guidance when getting started and reveal one or two tricks. Of course, this also applies to desoldering, which is not always that easy. Or maybe there are questions about certain topics?

I would be happy to receive feedback on this.

Otherwise, I'm preparing a short tutorial on how I do soldering and desoldering, although I'm not an expert, but I don't swear so often anymore when trying to connect things

 

[bernard_L]

Lead solder anytime. Lead-less solder is a pain for hand-soldering. And worse if de-soldering is needed. An opinion shared by professional at my former lab.
De-soldering. Best is the de-soldering iron, with hollow tip connected to a vacuum pump. But I can't justify such a purchase at home.
De-soldering. Proper braid has some flux. Cheapo has none. Lesson learned. De-soldering must be done efficiently with only the necessary heating time.

 

[koraks]

Lead solder anytime. Lead-less solder is a pain for hand-soldering. And worse if de-soldering is needed.

De-soldering. Proper braid has some flux. Cheapo has none. Lesson learned.

Absolutely.

 

[Sharktooth]

How do you strip the insulation off some of the tiny wires used in cameras?

I have a Canon QL17 where the battery lead wire broke. I thought it would be an easy task to resolder it, but every time I tried to strip off some insulation on the wire, the inner copper strands would break. Are there any tricks to do this?

 

[Andreas Thaler]

Unsoldering and soldering a cable to the circuit board of a Minolta X-700

There are many soldered cables on the flexible circuit board of the X-700.

I'll unsolder the blue cable.

The soldering station brings the soldering tip to 330 degrees Celsius (= 626 F). I use this temperature for soldering with leaded solder such as that found in the X-700.

As soon as the temperature is reached, I wipe the soldering tip on the damp sponge.

This is intended to remove oxide residues from the soldering tip, which prevent heat transfer to the soldering point. Cleaning is a constant process when soldering.

Now I briefly hold the soldering tip to the soldering wire and see whether the solder melts and a small drop of it remains on the soldering tip. It smokes a little. The smoke comes from the flux in the solder wire burning.

The drop of solder on the soldering tip allows heat to be transferred to the soldering point and the part to be soldered.

The yellow drops on the work mat are flux dripping from the solder wire. The flux is required for perfect soldering. Without flux, the solder does not connect the component to be soldered, e.g. a cable end, to the soldering point.

Everything is as it should be here. The soldering tip is now ready for soldering.

Before I hold the soldering tip to the soldering point, I add some flux. Since the flux evaporated when this solder joint was created, it now needs to be reintroduced. Soldering doesn't work without flux.

Now I hold the soldering tip with the small drop of solder against the soldering point until the solder melts. This takes about a second here.

I pulled the wire away with the tweezers, leaving the soldering tip at the soldering point. If I removed the soldering tip from the soldering point beforehand, the solder would solidify and the cable would not come off.

Now I want to solder the wire back on. I apply flux to the solder joint again.

I hold the soldering tip with a drop of solder against the solder joint until the solder melts. Using the tweezers, I push the end of the wire into the liquid solder and remove the soldering tip. I don't move the tweezers so that the solder can solidify undisturbed. After about three seconds I take the tweezers away.

The solder has now solidified and holds the wire on the soldering point.

Here I wasn't paying attention and crushed the cable with the tweezers. This can result in a short to ground in the circuit if the insulation is damaged. Then errors can occur.

Tools and materials for soldering: Soldering tools for working on the soldering point, tweezers, side cutters, soldering wire in various thicknesses, flux, soldering tip cleaner, desoldering braid and a heat-resistant work mat.

The required temperature can be set and kept constant at a soldering station. This soldering station has the soldering iron on the left and a hot air iron for contactless soldering on the right.

If the hot soldering tip does not accept solder despite being wiped on the sponge, it is time to dry clean it.

I use Tippy from Stannol for this.

Run the hot soldering tip over the cleaning agent a few times and the soldering tip is free of oxide again. In addition, the soldering tip is also tinned. Then wipe it off with the sponge and you can continue with soldering.

 

[moggi1964]

Thank you, nice to see this up close. Haven't ever done in-camera soldering but have done some audio stuff over the past 15 years or so.

Dug out my station to get an Ilford Exposure Monitor working again but haven't got around to it yet.

 

[Andreas Thaler]

Removing solder with desoldering braid

I prefer working with the desoldering braid because it is very efficient and I can control it better than the somewhat unwieldy desoldering suction pump. The latter sucks liquid solder from the soldering point using negative pressure.

The desoldering braid is a copper braid with or without flux. If it is held at the soldering point and heated with the soldering tip, it absorbs the liquid solder through the capillary effect.

A piece of desoldering braid goes into the tweezers and I add flux to it. This ensures optimal absorption of the liquid solder.

I hold the desoldering braid to the soldering point and press the soldering tip onto it, which has another drop of solder on it. This ensures the transfer of heat.

It hisses and smokes, I pull off the braid …

... and the solder on the soldering point is removed.

The desoldering braid holds the removed solder and is discarded.

 

[Andreas Thaler]

An extraction device with a carbon filter for the table prevents soldering fumes from spreading throughout the room. You should not inhale the fumes.

A desoldering suction pump

And never without it!

---

Soldering always remains tricky and sometimes I think the soldering tip has its own existence. Some days it likes me and some days it doesn't

Of course, the same applies here: never give up and practice!


+++

All information provided without guarantee and use at your own risk.

 

[Andreas Thaler]

Thank you, nice to see this up close. Haven't ever done in-camera soldering but have done some audio stuff over the past 15 years or so.

Dug out my station to get an Ilford Exposure Monitor working again but haven't got around to it yet.

You are welcome

Soldering audio can't be easier than cameras I guess?

 

[Andreas Thaler]

How do you strip the insulation off some of the tiny wires used in cameras?

I have a Canon QL17 where the battery lead wire broke. I thought it would be an easy task to resolder it, but every time I tried to strip off some insulation on the wire, the inner copper strands would break. Are there any tricks to do this?

For this I use Electronics Wire Stripping Shears from Knipex:

https://www.knipex.com/products/wire-strippers-and-stripping-tools/electronics-wire-stripping-shears/electronics-wire-stripping-shears/1182130?v=&sku=

The tool can be infinitely adjusted even for fine wires.

Here I inserted a longer piece of wire for demonstration.

When fixing the wire with tweezers while it is being stripped, you have to be careful not to crush the wire, as happened to me here.

 

[Sharktooth]

For this I use Electronics Wire Stripping Shears from Knipex:

https://www.knipex.com/products/wire-strippers-and-stripping-tools/electronics-wire-stripping-shears/electronics-wire-stripping-shears/1182130?v=&sku=

In my case, I don't think a better wire stripper would have helped. The tiny strands of core wire look to be oxidized and brittle after 50 years or so. It seems to be adhering to the insulation, and not separating easily, as with new wire. Any stress on these tiny strands causes them to break. I'm wondering if I can burn the insulation off, or chemically remove it.

 

[Anon Ymous]

I'm wondering if I can burn the insulation off, or chemically remove it.

Or perhaps replace it if you can reach the other end?

 

[koraks]

I'm wondering if I can burn the insulation off, or chemically remove it.

A cheap trick that I admit to doing rarely, is to touch the plastic insulation of the wire with the hot tip of the soldering iron at the point where I want to strip it off. Do this a couple of times around the wire and then pull the insulation off with your fingers. It's a bit of a crude approach, but it works in a (literal) pinch.

The drawbacks are the horrible smell, which I imagine is rather unhealthy, and the fact that the carbonized polymer fouls up the tip of the soldering iron. This way of stripping is also not particularly clean, since it'll generally leave a bit of an ugly edge to the insulation, but that's more of an aesthetic issue. The advantage is that you don't need any special tools for it, and also that you don't have to exert much force on the wire, which can be a bonus when working on something where you don't have a lot of space and you don't want to mechanically stress things.

 

[Sharktooth]

Or perhaps replace it if you can reach the other end?

It would have been better to replace the whole wire, but the other end was deeply embedded in the camera, and would have required major disassembly, and possibly even more problems Fortunately, the Canon G17 only needs the battery for the light meter. I just use it now with a handheld meter.

Koraks' suggestion to use a soldering iron on the insulation would be worth a try the next time this comes up.

 

[KerrKid]

Thank you for this write-up. I learned a lot.

 

[Andreas Thaler]

Thank you for this write-up. I learned a lot.

You're welcome, I'm happy for my part if it helps

 

[BMbikerider]

While on the subject of soldering I found that the bulb in my LPL7700MX enlarger was flickering when exposing onto paper, and as I print a fair bit of colour this was affecting the colour balance. Having looked at the ceramic bulb holder I found the the two terminal holes in the ceramic looked worn and the bulb was not held securely and not always making a good contact.

I took the bulb out of the enlarger head and separated the bulb from the holder then cleaned up the two terminal pins with abrasive paper and re-soldered the pins to make them slightly thicker and reinserted the bulb. The flickering stopped and has not returned!

The ceramic holder gets it's electricity via two heat resistant wires that disappear into the double walls of the enlarger head and getting at the wires to replace the terminal if you can find the way to take it to pieces I wish you luck, so it is a safe and easy way to do a repair.

 

[grain elevator]

In my case, I don't think a better wire stripper would have helped. The tiny strands of core wire look to be oxidized and brittle after 50 years or so. It seems to be adhering to the insulation, and not separating easily, as with new wire. Any stress on these tiny strands causes them to break. I'm wondering if I can burn the insulation off, or chemically remove it.

Ime cables in this condition don't conduct any more, there's no point in trying to delicately remove the insulation.

 

[cmacd123]

looks like the

Knipex 11 82 130​

German wire strippers are Only 117. Canadian Dollars at Amazon. Probably worth it, But I will really have to think about it.

Digi-Key shows them at CDN$105.92, so it is not that amazon is out of line.

Digi-Key Part Number

2172-1182130-ND

 

[btaylor]

Those Knipex are about $50 in the US. Good investment.

 

[Loose Gravel]

Nice job.

All the solder wick that I've used has flux built in. Smaller solder wick should be used with smaller solder joints. I leave it on the roll, wick the solder on the end, and then cut off the solder wick with the old solder. Once done soldering, the joint should be cleaned to bright and shiny with a cotton swab and isopropyl alcohol, even if it is 'no clean' type solder/flux because of its proximity to optical surfaces.

Tiny wire is usually stripped chemically. I don't know what the solvent is, but it is nasty. Any nicks in the wire is a no-no. Strictly forbidden, at least by NASA standards.

Wire insulation varies. Some melt too easily and some not at all. Teflon doesn't melt, but it 'cold flows' and should not be used. In a pinched condition, the insulation will eventually move away and allow a short condition. And some wire is just plain crap, even if it is in the camera already. It's all about cost in consumer products.

If one is solder very close to something that doesn't appreciate the heat, a small shield can be placed between the iron and other objects. A small piece of foil works.

We don't all have soldering irons as nice as the one shown here. I have an old Weller station and I crank it to the max. Get in and get out. Cheap irons, such as mine, cool quickly when touching a part, wire, or other thermal mass.

Don't blow the fumes, they should be sucked away. Create a draft with a muffin fan that gently keeps the fumes from you, the solderer. In labs where they solder all the time, a vacuum hose is nearby that vents the fumes away. Blowing on a joint to cool it is verboten. If cooling takes place too quickly, then the solder joint may freeze with stress in it.


Just my two bits...

 

[bernard_L]

looks like the

Knipex 11 82 130​

German wire strippers are Only 117. Canadian Dollars at Amazon. Probably worth it, But I will really have to think about it.

Digi-Key shows them at CDN$105.92, so it is not that amazon is out of line.

Digi-Key Part Number

2172-1182130-ND

I prefer this type of stripper, with pre-set openings for each wire size.

Cost me less than 20€; this precise model now discontinued but many similar ones exist. See at Newark/Farnell, Digi-Key, Mouser, etc.

 

[Andreas Thaler]

Is soldering with a soldering iron and soldering wire clear? So if you solder a wired resistor into the circuit board, for example? Or how to connect cables? Should I show this?

Soldering SMD components is a different matter, maybe someone would like to do a short tutorial on this? Although I've never had to replace electronic components on a camera circuit board before.

Or are there other wishes on the topic?

 

[4season]

Added to my shopping list:

• Silicone work mat
• Knipex wire strippers
• Flux pen (taking flux from a bottle isn't so convenient ...)

Already have:

• Hakko FX951 soldering station (But cheaper Hakko FX-888D ought to be more than enough for camera repairs)
• Chinese hot air SMD rework station (have not used for camera repair to date)
• SMD hote plate (ditto)
• Sparkfun ROHS solder, for new builds and servicing post-2004 items (love this stuff, flows beautifully)
• Radio Shack tin/lead/silver solder, for servicing pre-2005 items
• 30 gauge stranded copper wire, various colors (eBay, great buy for camera repairs!)

 

[Andreas Thaler]

• Knipex wire strippers

Knipex costs, but the quality is very high

Already have:

• Hakko FX951 soldering station (But cheaper Hakko FX-888D ought to be more than enough for camera repairs)
• Chinese hot air SMD rework station (have not used for camera repair to date)https://www.sparkfun.com/products/10243

I bought this combined soldering station a few months ago and I am very happy with it. Basic version, inexpensive, yet solid:

https://www.reichelt.com/de/en/soldering-station-and-hot-air-station-60-300-w-vel-vtss230-p289557.html

This review from Elektor convinced me: