Tektronix P6156 Probe Tip - Page 1
Forum section: electronics / testgear

author: TinkerGDS
author_rank: Contributor
timestamp: May 21, 2018, 01:03:34 pm
content: Good morning. I have a Tektronix P6156 probe. This weekend I was doing some testing and the probe tip broke off. I suspect it may have been cracked when I received it because it wouldn't have broken with the testing I was doing. This particular probe has the option for 1x, 10x, 20x, and 100x attenuation. When the probe was new it must have come with four probe tips to match each of the selected attenuations. I only received one tip. I have searched high and low, and even contacted Tek about a replacement tip. These are nowhere to be found. The part numbers of the tips are 206-0379-00, 206-0380-00, 206-0381-00, and 206-0382-00. These tips are 46mm in length and 3.5mm in diameter. Does anyone know if there's a replacement tip, or set, that is compatible with this probe?

author: MarkL
author_rank: Unknown
timestamp: May 21, 2018, 02:01:55 pm
content: Did the metal tip break, or was it the plastic bushing holding the tip?If it was the plastic bushing, I've been successful in gluing it back together with plastic solvent, and then putting pressure on the bushing (pushing it into the barrel) until the solvent dried overnight.My searches for direct replacements are coming up empty also.

author: TinkerGDS
author_rank: Contributor
timestamp: May 21, 2018, 02:36:48 pm
content: Unfortunately the metal tip and plastic bushing broke off. The ceramic "board", which must be the attenuating circuit, fell out of the tip too. I've seen some reference to hybrid tips, but I don't really know what that means and if it's compatible with the probe at all. It's really a shame. The probe was really nice, and came with the plastic case and all of the accessories.

author: MarkL
author_rank: Unknown
timestamp: May 21, 2018, 03:45:22 pm
content: Mechanically, given the measurements you provided, I think the probe tip assembly is the same as the P6139A probes that I have, and likely a lot of other probes from that era. It may be possible to find a cheap used tip assembly and pull the tip and bushing out and use it to replace your broken one as long as your resistive element is still ok. It's not supposed to come out, but given enough force it will.The tip assemblies are color coded to identify their model, so that would now be wrong, but whatever.I like Tek probes a lot, but having to replace the whole assembly due to a broken or mangled tip was just not a good design decision. I think "hybrid tips" is referring to the assembly with the tip and the integrated resistive element; what we've been talking about.

author: LaurentR
author_rank: Frequent Contributor
timestamp: May 21, 2018, 04:07:49 pm
content: If it is like the P6139A, Cal Test still sells their OEM version and have a pile of accessories available:https://caltestelectronics.com/ctitem/17-oscilloscope-probes/CT3290RAAccessories:https://caltestelectronics.com/ctitem/#!/35-35mm-probe-accessories/

author: TinkerGDS
author_rank: Contributor
timestamp: May 21, 2018, 04:39:21 pm
content: Thank you for the links. I looked at the second link and that's an exact picture of my broke probe tip. It's a blue one too, which must mean 10x. There's no information on the color coding in the P6156 user manual. But 10x is better than nothing.The broken ceramic piece in my probe tip came out of the tip assembly, not the probe itself.

author: LaurentR
author_rank: Frequent Contributor
timestamp: May 21, 2018, 05:33:21 pm
content: Quote from: TinkerGDS on May 21, 2018, 04:39:21 pmGreat. The Cal Test CT3290 is a 10X probe only and I believe it's the same for the Tek P6139A, so 10X is likely all you can get through them (maybe worth asking them though).

author: MarkL
author_rank: Unknown
timestamp: May 22, 2018, 12:04:59 am
content: To be clear here, the P6156 is a low impedance, 3.5GHz probe. The 10x probe tip assembly will give you an overall input impedance of 500 ohms.The P6139A is a high impedance, 500MHz 10x probe where the input impedance is 10Mohms. The probe tip assembly for a P6139A is not a replacement for the P6156.I was merely suggesting that you might be able to take apart (forcibly) a P6139A probe tip assembly, since it appears to be the same mechanical size, and use the needle tip and the plastic bushing that surrounds it to rebuild the P6156 tip assembly.However, if you're saying the long thin piece of ceramic is broken, that is your resistive element and I'm afraid the tip assembly is toast.All that being said, the P6139A is a nice probe and you probably wouldn't regret replacing your P6156 with one, unless you really needed the high frequency characteristics of a low impedance probe.

author: EE-digger
author_rank: Frequent Contributor
timestamp: May 23, 2018, 03:52:14 am
content: Check out the P6158. It's a 3GHz, 20:1 probe which also requires a 50 ohm input. While it is more compact than the P6156, the cartridge may fit.I've seen P6156 cartridges on Ebay in the past but the sellers apparently thought they had found sticks of platinum.

author: alm
author_rank: Super Contributor
timestamp: May 26, 2018, 11:15:35 am
content: Quote from: TinkerGDS on May 21, 2018, 04:39:21 pmThese probe tips have two coloured rings: the front ring near the tip and another ring near the back that goes into the probe. As far as I know, the back ring is always black for these probes, and the front ring matches the colours on the compensation box (black/blue/grey/red for 1x/10x/20x/100x). I doubt any other tips will work electrically (without board transplant) except maybe that from the P6158. It should be the same form factor (3.5mm) as the P6156 tips, and might very will be identical to the 20x tip for the P6156 (black/grey). Check the manuals for part numbers.On eBay usually loose tips seem to go for as much or not more than probes with tips.