Hi all,

I have a P6139A that appears to have a short in the compensator box. I've done the usual searches but have been unable to find a schematic.

Thanks Much
Joe

If you haven't seen this, then you haven't done all the "usual" searches!

http://w140.com/tekwiki/wiki/P6139

TekWiki should nearly always be the first place to look. The version of the manual is only "Operator's" and has no circuit details, but the reference to the whiskers in the connecting-cable might be of interest.
Colin.

Try posting in TekProbes@groups.io<mailto:TekProbes@groups.io>

Steve Lindberg

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986>; for Windows 10

On Sun, Aug 16, 2020 at 06:23 AM, Colin Herbert wrote:

the reference to the whiskers in the connecting-cable might be of interest.

I read the thread (from the link on the TekWiki page).... but, I don't see any evidence that "tin wiskers" are the problem. Also... in that thread... good P6139s.. were premised on having the cable replaced. How would you do that? (There's no part number for the cable...and I'm not even sure the probe comes apart... so that you could replace the cable... even if you could get one.)

On Sun, Aug 16, 2020 at 06:32 AM, Steve Lindberg wrote:

Try posting in TekProbes@groups.io

There's 2 messages there since April?

Thanks for the link. It applies to the P6139 not P6139A. Hopefully, but no guarantee, that the "whisker" problem was fixed in the "A" version. I will, however, fully disconnect the cable from the comp box to see which side the short is on.

On Mon, Aug 17, 2020 at 05:20 AM, Roy Thistle wrote:

There's no part number for the cable...

Later Tek catalogs had a section showing all spare parts for probes still in support.
Like this http://www.hakanh.com/dl/docs/probe_parts.pdf I think was scanned from the 1995 catalog.

and I'm not even sure the probe comes apart..

Unscrew the nut that surrounds the cable about half a turn and pull out the cable from the comp box.
On the other end, once the hook is removed, the body shell and tip could be unscrewed.

/Håkan

On Mon, Aug 17, 2020 at 09:50 AM, <joeschm@comcast.net> wrote:

Thanks for the link. It applies to the P6139 not P6139A

there little to nothing on the Tekwiki page (other than the title) that applies to just the P6139... everything is about/for the P6139A. (The link to the EEVblog post about the tin whiskers problem is talking about that very problem in the P6139A!)

On Mon, Aug 17, 2020 at 09:52 AM, zenith5106 wrote:

I'm not even sure the probe comes apart..

Yes. The compensation box and shell come off...but I said "I'm not even sure the probe comes apart... so that you could replace the cable"... replace the actual coax cable... not replace the "cable assembly."
Anyway there are no part numbers for the cable assembly (or for the coax) in the Tektronix P6139A Instructions (063-0870-05)... and I don't see a part number in the Tektronix catalogue scan you linked to.
Because of the 500 MHz BW of the P6139A... I believe that the reason that there is no part number for the cable assembly is that the compensation box, and the cable assembly coax, had to be matched by Tektronix at the factory?
There is no replacement cable assembly for a P6139A probe?... if the cable assembly is bad...one just has to get a new (or another working) P6139A probe.

On Tue, Aug 18, 2020 at 07:00 AM, Roy Thistle wrote:

so that you could replace the cable"... replace the actual coax cable... not replace the "cable assembly."

OK, so you want to replace the cable only and mount the connectors yourself ?
As far as I know that can't be done. You won't find the cable or connectors for sale by Tek or anyone else.

I don't see a part number in the Tektronix catalogue scan you linked to.

Check again. On page two the P/N is shown as 174-0978-00.

I believe that the reason that there is no part number for the cable assembly is that the compensation box,
and the cable assembly coax, had to be matched by Tektronix at the factory?

That would have left out the P/N for the comp box too, don't you think ?
I don't why the P/N wasn't in the manual on Wiki. Earlier versions of the same document showed the P/N as usual.
There are several adjustments inside the comp box and instructions for those should have been in the manual too.

/Håkan