Tek P6015 thoughts - Re: Very nice High Bandwidth 75MHz HV Probe on EBAY ! ! !

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Ken,

The "old style" P6015 Tek probe used Freon 114 which is what the little can 
had in it.  I just had an empty one here on the desk but I tossed it with 
last week's trash (empty).  The can held enough for just one full 
refill.  You would unscrew the end of the probe and just "pour" it in and 
quickly replace the cap before it evaporated or the fumes suffocated you 
(cool in the 60's, but out of place now-a-days...).  Freon 114 is no longer 
available and a full can is probably worth more than the old probes 
now.  114 had a fairly low vapor pressure and could be "handled" without 
too much trouble (much like "1-1-1 tricky").  But the old probes will have 
bad seals after all these years so don't even bother trying to fill them 
now unless you can replace all the seals (they got pinched real easy 
too).  One may "dream" of using other freons but forget it.  Most will 
remember this funny picture I took ;-))

http://hot-streamer-dot-com/temp/P5200028.jpg

I should note that the old freon may have water in it so you should check 
the inside for corrosion and recheck the solder joints inside the probe 
especially to the BNC connector (a famous broken solder joint place).

What I found was that the dielectric constant of regular mineral oil was 
"close enough" to F114 for the probe.  That is what I have in mine 
now.  The challenge is recalabrating the "box":

http://hot-streamer-dot-com/temp/2003-05-20-09.jpg

I never did find the "real" instructions, but a call up to the "right 
person" at Tek informed me that it was all trial and error.  You just get 
out a signal generator and fiddle with it and you will figure it out in 
about an hour.  She was right, you soon get a feel for what each of the 
adjustments does and then you just set it right.  So I would highly 
recommend refilling with mineral oil.  I do note that some of the 
adjustments are near the ends of the travel of the adjust screws but I 
think it all will calibrate in fine with mineral oil.  It does seem to have 
problems with fast high speed stuff (my gap VI measurements) but apparently 
the "original claim" of beautiful 75MHz flat response was good for the 
early 1960's, but sort of a funny joke these days.  The probe really is 
pretty "funky" and the giant grounded body provides massive local 
capacitance to anything high voltage near it.  It was wonderful in the 
60's, but pretty poor compared to the performance standards now days.  The 
"box" is supposed to calibrate air too.  I was wondering if I could find an 
air one too see just how bad or good the mineral oil conversion was.  But I 
get the impression I did real good...

I should STRONGLY note that the rated voltage of 40kV (or 20kV with no 
freon) ratings of this probe are NO JOKE!!  There ain't no 500% safety 
margin.  These are from the "explosion - 1%" days of safety 
engineering.  Mine with air in it arcs at 22kV!!  I really wound not 
consider it for any "high power" HV measurements.  The "safety" of these 
probes is 1960's style, not 2003 CE.  I fear plugging it between HV and a 
$4000 scope (my money!).  The newer silicone oil P6015A helps the voltage 
breakdown problem...  I am hoping the mineral oil will really help the 
breakdown problem too...  But in any case, you don't want to go connecting 
these to a pole pig (residential distribution transformer)!!

The "latest" version (P6015A) is filled with silicone oil and has a whole 
new "box".  I am not sure the old box could calibrate silicone 
oil.  Really, it is time for Tek to make a fully "modern" version.  These 
probes will never pass any modern performance or safety standards now 
days.  The P6015 series is really long overdue for retirement...  Tek is 
sort of ashamed of the 6015 style these days, but they still fill that nich...

In contrast, the fully modern Tek 5200 is a "perfect" probe.  It only does 
2500 volts, but the circuit loading, bandwidth, safety, performance... are 
second to none!!  Their performance is simply perfect!!   They command a 
darn good price (I think Tek just raised it)!!  I also have some "similar" 
rated probes from the "other guys" (TPI) that just suck in comparison, but 
they only cost $50, so they are good for stupid stuff ;-))

So the old P6015 or a pretty good buy if you watch out for the safety, 
circuit loading, and pretty odd high frequency performance.  Just fill them 
with mineral and recal them with a signal generator, an hour of time, and a 
few beers ;-)).  But they definitely are a 50 year old design and connected 
to a computerized scope of today they will show all kinds of 
"issues".   But even "theoretically" perfect probes like the vacuum 
Jennings 60kV are pretty "interesting" if you push the 1960's specs against 
today's standards...

http://hot-streamer-dot-com/temp/2003-05-20-03.jpg

Dan (or the Captain) just made a home brew probe that was extremely 
interesting and had some modern design techniques behind it!!  I wound not 
be surprised if it easily outperformed the P6015...

Cheers,

         Terry



At 09:50 AM 6/17/2003 -0500, you wrote:
>What exactly is in the little can, and where do you get more?
>
>KEN
>----- Original Message -----
>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: <tesla-at-pupman-dot-com>
>Sent: Tuesday, June 17, 2003 8:41 AM
>Subject: Very nice High Bandwidth 75MHz HV Probe on EBAY ! ! !
>
>
> > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
><dhmccauley-at-spacecatlighting-dot-com>
> >
> > There is a very nice HV Probe on EBAY right now.  These tektronix probes
> > work extremely well and have high bandwidths of up to 75MHz.
> >
> > An excellent addition to anyone looking to look at the high frequency
> > waveforms associated with their tesla coils.
> >
> >
>http://cgi.ebay-dot-com/ws/eBayISAPI.dll?ViewItem&item=2538831249&category=45008
> >
> >
> > The Captain
> >
> >
> >