Author Topic: ToneOhm, any similar products?  (Read 4574 times)

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Offline Chris Wilson

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ToneOhm, any similar products?
« on: June 23, 2013, 06:45:59 pm »
Very taken with how easy a friend found a shorted cap using a ToneOhm. It was the model with the AC whatsit and quite expensive, but as he uses it commercially it's not a big deal for him. Are there any similar products to look out for, used? I can't believe these are the only ones, although my pal knew of no competitors. Thanks. Any idea of cost for used ones would be appreciated. I see Aurora posted in 2011 how he picked one up off Ebay for £50 UK Sterling. Jammy devil..... ;)
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                 Chris Wilson.
 

duskglow

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Re: ToneOhm, any similar products?
« Reply #1 on: June 23, 2013, 07:05:41 pm »
Wow, Dave could have used that with the LeCroy.
 

alm

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Re: ToneOhm, any similar products?
« Reply #2 on: June 23, 2013, 10:09:02 pm »
Bob Pease published a design for something similar in his book 'Troubleshooting Analog Circuits'.
 

Offline Chris Wilson

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Re: ToneOhm, any similar products?
« Reply #3 on: June 23, 2013, 11:07:57 pm »
I have found the book on line, the circuit looks pretty simple, I may have a go at knocking one up, it sure looks useful. Thanks very much for that! In fact the book looks very interesting and a cursory glance shows it to be very readable. I am going to have a proper look at it.
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                 Chris Wilson.
 

Offline Fraser

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Re: ToneOhm, any similar products?
« Reply #4 on: June 23, 2013, 11:40:05 pm »
The ToneOhm is a superb bit of kit if you are faced with suspect power supply bypass caps or similar low resistances/impedances across PCB tracks. The key features are as follows:

1. Ability to measure milliohm resistances to trace a short or low resistance by looking for the lowest reading.
2. Ability to inject an AC signal onto a suspect pair of PCB tracks and trace the signal along the track until the location of the short using a inductive probe. The ToneOhm will only generate its AC signal when it 'sees' a low resistance/impedance so it does not work like a cable tracer and cannot be used to reverse engineer PCB track layouts.

I know of several milliohm meters that can trace a short along the tracks but I know of no other unit that has the AC injection and inductive 'trace to short' probe. It is the inductive trace mode that is considered the clever feature in the design. The inductive probe is a passive 2 wire inductive pick-up but I have no tech detail for making one.

I have bought several Polar ToneOhms since the first (and best) GBP50 850 model. I presently have some 750 and 550 units as well. The new inductive probes cost me GBP50 each from Polar, so I couldn't sell them at bargain prices I am afraid. A pile of 5 EX MoD ToneOhms sold on ebay the other day. Average condition and no inductive probes, so bear in mind you will face a GBP50 additional cost if buying one without the probe.
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Offline JimmyMz

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Re: ToneOhm, any similar products?
« Reply #5 on: June 23, 2013, 11:40:59 pm »
There is a somewhat similar device, and Dave Miga just rolled out a new version: http://www.eds-inc.com/leak.html
~250-300 US dollars
« Last Edit: June 23, 2013, 11:46:38 pm by JimmyMz »
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Offline Fraser

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Re: ToneOhm, any similar products?
« Reply #6 on: June 23, 2013, 11:45:01 pm »
Clever, but no inductive tracing capability which is ToneOhms advantage on multi-layer boards especially.
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Offline Fraser

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Re: ToneOhm, any similar products?
« Reply #7 on: June 23, 2013, 11:46:50 pm »
OT but maybe useful....I also would not be without my Huntron Tracker and Tektronix TR210 (Huntron HTR-200)
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