Tektronix P6042 repair problem - Page 1
Forum section: electronics / repair

author: TmaxElectronics
author_rank: Regular Contributor
timestamp: October 15, 2023, 12:30:50 pm
content: Hey all,I recently scored a Tektronix P6042 Current clamp form the dumpster and have started a repair attempt on it.The problem boiled down to a broken cable (a video with proper explanation is in the making), but I'm having trouble finding a suitable replacement. I don't think cutting the cable shorter is a real option since there is a break in almost all conductors (only one coax and two signal lines still work). I'm a bit suspicious of the cable anyway and would like to replace it.Has anybody found a nice replacement for it? Especially the combination of dual 50 Ohm coax and signal lines in one cable is something I've never seen before, not to mention know where to get. VGA cable is the closest I could think of. That might work if I just use some of the coax for the low frequency hall-effect signal, but I suspect the 75 Ohm impedance mismatch would noticeably reduce the bandwidth.

author: jonpaul
author_rank: Super Contributor
timestamp: October 15, 2023, 12:49:11 pm
content: Indeed the 6042 custim made TEK Cable is suseptible to intermittents and breaksThe probes are often damaged as even a few cm fall on a hard floor can chip or harline crack the fettire split cores.It is not sure the coax is 50 Ohm, see the servive manual on TekWiki, W140, Bama etc.Doubt you can find the origianl TEK cable but try the TekMuseum.Bon chanceJon

author: alm
author_rank: Super Contributor
timestamp: October 15, 2023, 01:24:30 pm
content: There has been a fair amount of discussion on the probes on theTekScopesandTekScopes2groups. Most fixes I remember consisted of shortening the cable on one of the ends, usually the probe end since that experiences the most stress. Do you have any way of detecting where the breaks are? Like seeing if resistance change when you flex the cable at a particular spot, or TDR?I remember reading about people using an HDMI cable or making their own cable using thin coaxial cables like RG-174 or RG-178 and flexible heat shrink.

author: KrudyZ
author_rank: Frequent Contributor
timestamp: October 16, 2023, 01:14:52 am
content: I've had quite a few of these over the years and repaired one of them with RG175 and some multi-conductor cable.Not pretty, but it worked.In my experience the cable tends to break on the amplifier side, not the probe side, since they chose to do their strain relief by putting a really tight bend into the cable where it enters the box.

author: TmaxElectronics
author_rank: Regular Contributor
timestamp: October 16, 2023, 11:07:24 am
content: QuoteHDMI sounds like an interesting idea, especially since they exist in much more flexible form than vga. I'll definitely be looking into that.QuoteI don't really have any tdr equipment (or idea how I could set it up with the stuff I have), but I tried both flexing it as well as a frequency sweep but both gave inconclusive results. Especially the flexing seems to suggest breaks at multiple locations within the cable.But I'll just try cutting a bit off of the side in the amplifier, maybe I get lucky. Worst case I have to throw away the cable, which I wanted to do anywayQuoteI sure don't hope that's the case. The dumpster was at least padded with a ton of IGBTs and capacitors, maybe they softened the fallThanks for the tips, I'll report back once I decided what way I'll go with the repair