[Test-Equipment] Repair HP410B (triax cable request)

[Barry]

Hi Rob,

Yes, the molded plastic strain relief is nice to have as long as the triax is good.  When it fails, though, you have to do the best you can with what you've got.

In the case of this meter, the triax is is in pretty good shape so am considering leaving it alone.  It could use new wire on the Common and Ohms leads but those are pretty easy.  Not sure about the DC lead.  It may also be good as well.

Thanks for the reply!
Barry - N4BUQ

----- Original Message -----
> From: "Robert Myers" <rsmyers at rogers.com>
> To: "Discussion of Electronic Test Equipment" <test-equipment at mailman.qth.net>
> Sent: Friday, September 26, 2014 9:53:06 PM
> Subject: Re: [Test-Equipment] Repair HP410B (triax cable request)
> 
> You say you 'may' need to refurbish the cable.  But you might want to see if
> you can salvage the original cable.
> 
> It has a rectangular molded polystyrene piece -- molded right on to it at
> the end that is housed within that bottom metal plate -- that gray bottom
> plate that covers the place where all the cables are soldered to the female
> receptacles that are mounted on, and go through to the top of the upper
> phenolic piece.   It is to provide a countering torque that will be required
> during (the necessary) external portion of the cable's manoeuvring.  It is
> to ensure no rotation beyond the entry point plug-in/out module.
> 
> Now, that same metal cover plate has sort of semi-circular holes in it that
> 'grip' the various exiting cables good and tight at that exit point --
> tighter as the metal plate is tightened down against the phenolic top
> portion of the small cable junction enclosure (the cable 'plug-in/out
> module,' of the main HP-410B unit).  This also, is to prevent the user's
> manoeuvring of the cables (during measurements) from causing a turning of
> the cables within the plate/ phenolic enclosure that makes up that removable
> 'plug in unit' at the bottom of the HP-410B.  Turning inside would quickly
> break the solder connections - as you can imagine).  But it alone, is not
> enough to prevent turning of the triaxial AC/RF probe's cable - it needs
> more.
> 
> The already mentioned rectangular molded piece is the additional measure
> used to stop the triaxial cable from rotating (under the metal cover, that
> is) and thus loosening, and eventually breaking the solder connection.  That
> is the only cable with that molded piece.  It is required on that cable in
> particular (and not the others) because that cable is stiff-'ish' and
> turning it to measure something can easily translate into a high torque at
> the solder point.  I the case of the cable, the tight exiting hole on the
> metal cover are not sufficient.
> 
> If you open it up you will see what I mean.
> 
> Regards,
> --- Rob
> VE3JQL
> 
> 
> -----Original Message-----
> From: Test-Equipment [mailto:test-equipment-bounces at mailman.qth.net] On
> Behalf Of David DiGiacomo
> Sent: September-25-14 1:02 PM
> Cc: Test Equipment
> Subject: Re: [Test-Equipment] Repair HP410B (triax cable request)
> 
> On Thu, Sep 25, 2014 at 9:39 AM, Barry <n4buq at knology.net> wrote:
> > I have an HP410B I'm going to refurbish.  As part of that process, I may
> need to replace the triax cable that feeds the AC probe.
> >
> > I think Belden 9222 is a possibility; however, I don't find that online in
> anything less than 100 ft. spools and at more than $1 per foot, that ends up
> a bit cost-prohibitive.  Anyone happen to have any of that for sale (by the
> foot)?  I think the original cable is about 4 feet long.
> 
> 
> Would this work?
> 
> http://www.ebay.com/itm/36-Trompeter-P1A3T10PDB-36-Cable-Assembly-Triax-TRC-
> 50-1-BNC-M-TRC-M-NOS-/311087878350
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