AIM TTI iprobe 520 Current probe-Does anyone use this instrument?

[djsb]

I've just bought one of these probes and would like to know if anyone is actually using this instrument. If you have one, you will already have viewed the review video by Dave Jones.
Basically, I'm trying to convince myself that my money hasn't been wasted and that the tool can be used to track down and diagnose faults.
Please post your experience with the probe here. Thanks.

[slugrustle]

I've got one of these but admittedly haven't used it a whole lot.  I bought it before I had the cash for a Siglent CP5030, thinking it had pretty good accuracy, range, and bandwidth for the price and that the trace measurement feature was kind of a bonus.

So I've mostly only used the probe in wire mode when my CP5030 has been out for calibration.  It works well enough, although if memory serves, I had to let it warm up for a while before the zero point stopped drifting.  It was stable after that.

I also had planned to be doing more power stuff than I ended up doing after a slight change in my job, hence not really using the trace measurement feature much.  I also have one of those thin wire Rogowski coils, which is somewhat preferable in a power electronics context because it doesn't need to be held in place.  I did use the iprobe in field mode to take measurements on an eraser for a magneophoretic writing surface once, and it was quite useful for that purpose.  Can't do that with a normal current clamp.

[MarkL]

I have one of these for over 10 years now.  I purchased it before I saw Dave's video.  I do not use it often, but it can save a lot of time when the situation is right.

Some things I've done with it:

- Finding where CMOS 4xxx latch-up was occurring in a product.  Raking the tip of the iProber across all suspected chip pins found the aberrant current flow in a few minutes, and down to the exact pin.  A fix was provided to the client.  I bought the iProber for this short consulting stint, and it paid for itself.

- Locating stray ground current in an Apple linear power supply by running the tip along the ground connection starting at the incoming AC.  Turns out Apple ran the ground wire *through* the transformer core, apparently to save running the ground around the outside in the already tight case.  This created a 1/2 turn transformer.  Duh.

- On a mutli-layer board with a totally corroded via and no schematics available, I was able to discover the buried path of the signal that used the via on a known good board.  This was done by injecting a small AC current on the signal endpoints on the known good board and using the iProber to follow the signal from the top of the board.  The corroded board was fixed with a jumper on two points where the signal surfaced.

Things that I don't usually use it for:

- Measuring free space magnetic fields (actually, never).

- Using the snap-on current clamp.  The readings vary too much depending on the wire position.  I have other AC/DC current probes that are more consistent (Tek TCP202, Tek A6302, etc.).

- Measuring small DC currents.  I find the sensitivity to the earth's magnetic field to be annoying when trying to trace small currents.  The probe has to be held at the same angle and orientation while moving it around, and it has to be kept away from any other magnetic materials, even screws holding down my bench top.  I wish it had a 3-axis Hall sensor in the body to null out some of the external affects (future project).  I always try to work with AC signals when using it for this reason.

Other complaints:

I've had the adjustments on the inside of the probe head get intermittent (as in potentiometer failure).  My "fix" was to tweak each potentiometer in and out of the "dirty" zone to stop the output from jumping randomly.

Also when I had it apart, I noticed a severe problem with tin whiskers on the inside of the shield case.  I cleaned them off and sealed the shield with several layers of insulating varnish.  I haven't had it open for the last several years to see if it recurred.  I initially thought this was the source of the instability.


The iProber is far from perfect, but it does have areas where it can excel.  I don't regret buying one, but it certainly would not be an initial "must have".  If you're looking for more excuses to keep it, search around for people's stories using the old HP 547A current tracer.  The iProber is a modern-day version of that.


EDIT: Fixed some typos.