Wavetek / Fluke ? SF10 short finder -A very useful tool if you can find it

[Fraser]

A few years ago I was hunting for a decent continuity tester to assist in tracing component interconnects on PCB's whilst reverse engineering for repair work.

I stumbled upon an unusual unit from Wavetek named the 'SF10 Short Finder Brush' I could only find it available in the USA but as it was on offer at US$19 the additional postage cost wasn't too much of an issue.

What makes this unit unusual? Well take a look at the picture. It has the normal multimeter like test probes for point to point continuity testing, plus a stainless steel brush. With the brush the user can pick a point of interest on a PCB circuit  with the cabled test probe and then 'scan' the PCB with the brush until continuity is found. The brush is then replaced with the probe, at the other end of the unit, to zero in on the continuity point. It is designed to provide a continuity indication beep no matter how fast the brush is moved across the PCB. It also uses semiconductor safe voltages and currents, unlike some continuity testers designed for electrical work.

Details are here:

http://www.tequipment.net/WavetekSF10.html

http://uk.rs-online.com/web/p/continuity-checkers/3389851/

Is it any good ? Well I ordered a couple of the units from the USA and can confirm that it is very well made and VERY quick to respond to continuity. I used it in anger today to reverse engineer a multi layer PCB that had issues. I was able to quickly locate the main interconnects between the chips of interest and it was much faster than the point to point testing that I have done with my Fluke 87 III.

Does it have any flaws? Well maybe....it cannot be used on PCBs that have been marinised or coated with varnish. But then that is true of any contact probe unless you pierce the insulation. You can also use the brush on the component side of the PCB if that is not coated.

So why did I say 'if you can find it'....well for some reason Wavetek/Meterman have discontinued this useful tool and no equivalent appears to be available. You could probably make something similar if you can find a metal filament brush and a very fast responding electronics safe continuity tester. For US$19 it was a bargain though.

If you do any PCB reverse engineering I recommend this continuity tester so if you spot one....consider adding it to your tool kit. A simple idea that works well.
 

[toli]

Why not build on yourself? Now with 3D printers being so wide spread I'm sure you can find someone who can even print a nice case for it, and the circuit isn't complicated at all.
Or even easier, just make a similar brush "probe" for your DMM (assuming your DMM is fast enough on the continuity range). I'm sure its possible to figure our a method to place both the brush and the normal sharp probe tip on opposite sides of the same silicon/plastic handle. I might even give that a try one of these weekend if I can find the time

[Fraser]

A DIY solution id definitely possible. A chap on Instructables made a version of it with a multimeter connected to a foil finger cap but that isn't quite the same IMHO. A metal brush connected to a fast multimeter, as you suggest is a better plan.

http://www.instructables.com/id/How-To-Quickly-Find-And-Trace-PCB-Tracks-1/

I don't actually need another as I have one, and a spare    The clever bit is really the fast responding continuity tester. It is as fast, or faster than my Fluke III beeper circuit and provides fast audio feedback, indicating that you have just passed over the continuity point for which you are hunting.

I will take a picture of the units internals for anyone wanting to build their own. The low test voltage and low current is crucial for such a unit.

I have found a price for when the unit was available in the UK....GBP39 (~$60) so it wasn't exactly cheap but it is well designed and built.

I just noticed an interesting label on the unit:

"WAVETEK is a trademark of Wavetek Wandel Goltermann Inc. (WWG) and is used by  Fluke under a transitional licwence agreement. Fluke is not affiliated with WWG"

So Fluke were involved in this unit ? Could it be that it is actually a Fluke product with Wavetek labelling ? That would explain the excellent performance and quality of the product, and possibly its discontinuation ?  Interesting  I have amended the title of this post to reflect this possibility.

[Fraser]

Internal pictures 

It contains a LP324 and two TL555C's ....nice and simple 

Easy to repair if I fry it !

http://www.ti.com/lit/ds/symlink/lp324.pdf

http://www.ti.com/lit/ds/symlink/tlc555.pdf

[peter.mitchell]

cable "ringers" are also incredibly useful, essentially, you connect a tone generator to one end, then a receiver "wand" is waved over the cables, and the one that makes the wand "ring" is the one the generator is connected to. Incredibly useful for wiring harnesses and large scale cabling.

[dds737]

Just won this exciting tool (SF10) on ebay, looking  forward to use it

[marc.hickling]

Hi this is an old post i know, but... Im looking for a replacement brush or alternative for this product. Anyone got any ideas? I know the company is now bust but its an incredible tool can anyone help?

[Fraser]

Sadly I have not found any original manufacturers spare brushes, hence why I purchased more than one unit to last me longer. I would think some form of brass or steel bristle brush could be modified to replace the original bit finding a long rasa or steel bristle brush is the chalkenge as you no doubt know. Sadly the circuit inside the unit is not compatible with carbon, or carbon impregnated filaments.

The unit is sadly discontinued but it was sold under different brand names. Wavetek, Meterman, Amprobe and Fluke. None of them provided a replavcement brush assembly even when stil, a current product.

I will have a look around to see if I can spot any long metal bristle brushes. They are the sort of thing used in some types or art and for cleaning metal so a suitable brush may be out there somewhere. There are cleaning pencils that contain a choice of glass fibre, steel or brass inserts that retract when not in use. A little like a propelling pencil. The replacement inserts are cheap enough and could be combined to form a wide brush ?

Another possibility is to make a new brush by cutting many lengths of very thin spring steel wire to form the brush. Sadly that would be hard work though.

Fraser

[TheBay]

cable "ringers" are also incredibly useful, essentially, you connect a tone generator to one end, then a receiver "wand" is waved over the cables, and the one that makes the wand "ring" is the one the generator is connected to. Incredibly useful for wiring harnesses and large scale cabling.

I had a Power Probe ECT 3000 when I was doing a bit of Auto electrical, fantastic bit of kit.

[kripton2035]

idea to replace this steel brush (combining 2-3 of them) :
https://www.ebay.com/itm/Scratch-brush-brass-steel-nylon-fiberglass-set-watch-repair-rust-clean-tool-mix/112140712886

[Getorix]

Hi everyone.

I would like to share DIY alternative to SF10 which I have been using for some time already and it works perfect.

Here is what you need:

1. QianLi ToolPlus iBrush DS1102 Multifunctional Steel Brush (easy to find on AliExpress or UnionRepair)
2. hook-up wire
3. male crimp pin for 0.1"
4. heat-shrink tube
5. duct tape

The good thing about this brush is that brush wires are all connected and exposed on top of the brush.


Assembly is pretty straight forward. Crimp wire with male pin then wrap into hear-shrink tube. Throw wire on top along the brush handle fixing it with duct tape.
Wire should be long enough to reach the other end of a brush. Strip pretty decent part of the wire to make better connection with brush wires. Spread individual internal wires of your hook-up wire over the brush wires.
And finally a tricky part - make it stick somehow. I used solder but glue probably is a lot better option.

This is what it looks like assembled.

[Fraser]

Is that brush handle made from aluminium ? If so, you could also drill a hole in the end of the handle and fit a 4mm test lead cable into the hole by some suitable means. A 4mm socket could also be installed. I would achieve the fixing by drilling a hole in the handle for the wire or 4mm socket and then another hole at right angles to it for either a machine (tapped hole) or blunt ended self tapping screw.

Great idea and thank you for providing details of the brush 

The SF10 remains a front line PCB reverse engineering tool for me

Just thinking about it as I write this...... if a 4mm hole can be drilled into the aluminium handle, a 4mm multimeter test lead with banana plug termination would plug straight into it a

Of course, if the handle is just silver plastic then all this is moot.

Fraser

[Getorix]

Yeah, it is solid piece of aluminium I think, definitely not plastic. But drilling into it for banana plug is an overkill for me
Even if it is my second most important tool for PCB RE after X-Ray

[Fraser]

Yep, found it in the UK..... £23 though 

Description states that the handle is aluminium  So get your drill out, fit a 4mm drill bit, and get drilling that handle 

“ High temperature resistance steel brush, ideal for use when working with PCB boards.
Easily remove and clean residue when repairing logic boards.
Strong aluminium handle with magnetising function.”

https://www.ebay.co.uk/itm/Qianli-ToolPlus-iBrush-Multifunctional-Steel-Brush-PCB-Board-Repair-High-Temp/274153106297?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D225076%26meid%3D6243f0a1c2544809ab01148ded4d99b5%26pid%3D100675%26rk%3D1%26rkt%3D15%26mehot%3Dnone%26sd%3D274153106297%26itm%3D274153106297%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Ad6b4b637-7739-11ea-928c-622c255b94b5%7Cparentrq%3A4a5618ea1710a4b7b67e0f26fff69b86%7Ciid%3A1


Fraser

[Fraser]

Getorix ..... I sold all my high resolution X-Ray kit 

It had to be done though as I was not justifying its cost with enough use.

Fraser

[Fraser]

Another ‘bush engineering’ solution might be to buy a cheap brass or steel bristle pipe brush and just bend the appropriate length of brush at a suitable angle. Attach a croc clip test lead to the metal handle and away you go  Cheap and cheerful but in plentiful supply 

fraser

[kripton2035]

@Fraser : it would be nice to reverse the schematic of this little device, as it is no more sold...

[kripton2035]

this is what I can draw from the pictures you posted earlier.

[Fraser]

Sadly I am pretty much buried in project work at the minute so cannot RE the SF10 for a while.

Fraser

[masterx81]

I use a similar approach using the crocodile clip of the multimeter and a dremel 3mm brush... the brush have near 1.5cm of diameter

[kripton2035]

there is one available here : https://www.ebay.com/itm/233643552361
sorry too much for me !

again if someone could open one and make good pictures it would be easy to clone...

[Fraser]

That asking price of $250 is plain crazy. Surely a typo. I see the seller is open to offers so possibly just testing the market for best offer ?

I have six of these units and to date have only used one as it is well made and has yet to fail me. Maybe I should sell some of my excess ? 

Fraser

[Fraser]

I must say that I am surprised that another company has not resurrected this type of unit. I use it in every PCB Reverse Engineering project I undertake and would not be without it. It saves me so much time 

Fraser

[Fraser]

A teardown is to be seen here

https://eladorbach.blogspot.com/2020/05/teardown-wavetek-meterman-sf10-short.html

Fraser

[Fraser]

The patent includes some schematic detail

https://patents.google.com/patent/US5397996A/en

Fraser