WTB HP428A/B/D Probe

[jeffjmr]

Need a working probe for the HP 428 series Dc Current meters part number 428A-21A also known as 00428-62101.

Thanks,
Jeff

[bob91343]

I believe the probe is the same for the A model so that may widen your search.  The probes are matched to the instrument so you will experience some calibration error I suspect.

[jeffjmr]

Thanks, Bob.

Yes, I think the part number is the same. I edited the heading.

I had heard the probes were matched.  But the calibration process in the manual is lengthy. I was hoping that would makeup for any differences.

Jeff

[Stray Electron]

  I have two 428s and one has a probe but the other one doesn't. As you've already found out, the probes are just about impossible find by themselves and it's difficult to find a meter with a matching probe.  In short, for any TE other than a low end multimeter or low end scope, I've found that probes by themselves cost almost as much as complete set. Now I no longer buy any high-ish end TE that doesn't include probes unless I KNOW that I can get probes at a reasonable price.

[bdunham7]

They're out there, but you have to beat the bushes.

https://www.torontosurplus.com/hp-00428-62101-agilent-00428-62101-current-probe.html

[factory]

As mentioned in the other recent thread, the probes are still made for a modern version of this meter, probably the only way to guarantee you'll get a working probe, at a price of course.
Or look for one second hand, with or without the meter and hope it's working.

They are still made for the 428D from Applied Physics, but probably cheaper to look for an old 428A/B probe on ebay.

https://www.appliedphysics.com/products/magnetometers/

David

  I have two 428s and one has a probe but the other one doesn't. As you've already found out, the probes are just about impossible find by themselves and it's difficult to find a meter with a matching probe.  In short, for any TE other than a low end multimeter or low end scope, I've found that probes by themselves cost almost as much as complete set. Now I no longer buy any high-ish end TE that doesn't include probes unless I KNOW that I can get probes at a reasonable price.

Not surprised that probes & power cords etc. go missing, certainly where I work the TE stays in the storeroom until required and leads tend to get kept at the benches. Then when they decide to clear out old gear it often goes without the leads. I imagine this happens at a lot of places. Difference where I work is the redundant TE is not sold.
Also if they get damaged, it's possible they would have been thrown out to stop people using defective leads, of course they might keep the meter unit for spares, if they have more than one.

David

[bob91343]

I got a busted B model with no probe, a cracked meter, and no tubes.  I convinced the guy at a swap meet to give it to me free.  I swapped in the probe and tubes from my A model and a meter glass from a junker 412 and I am good to go with a Franken 428B.

[jeffjmr]

  I have two 428s and one has a probe but the other one doesn't. As you've already found out, the probes are just about impossible find by themselves and it's difficult to find a meter with a matching probe.  In short, for any TE other than a low end multimeter or low end scope, I've found that probes by themselves cost almost as much as complete set. Now I no longer buy any high-ish end TE that doesn't include probes unless I KNOW that I can get probes at a reasonable price.

Yeah, that’s a good policy. This was a rookie mistake on my part.

Jeff