Date
1 - 19 of 19
TN500 Plugin 067-0699-99
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bobh@joba.com
Does anyone have any information on a Tektronix TM500 plugin 067-0699-99?
It's a Milliohm-Voltmeter with a LCD front panel display.?? It has two front panel Ohms connectors labeled Hi and Lo, a range switch (0.1, 1, 10, 100), Volts - Ohms switch, Volts jacks labeled Hi and Lo.?? It has Tek serial number label. A very cursory check on TekWiki didn't find anything. Unfortunately it followed me home sans milliOhmeter probes. Bob.
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Vince Vielhaber
I don't know what connectors are on your plugin, but milliohm meters
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typically take a 4 wire probe set. Two wires from each probe tip to individual plugs to the meter. Often a piece of coax, like RG174 is used for the two wires to each tip. You can either buy or make the probes, I made a set for my Polar Toneohm and it works great. Or you can buy them for as much as a few hundred dollars - your choice! Vince - K8ZW.
Does anyone have any information on a Tektronix TM500 plugin 067-0699-99?
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Hi Bob,
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Vince is correct if what you have is a precision instrument or ... you can find a set of kelvin clip leads for $10 to $20 on eBay from China that will probably do just fine for a plugin that cost about the same as the Chinese Kelvin clip leads. Dennis Tillman W7PF
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Vince Vielhaber Sent: Thursday, September 05, 2019 5:04 PM I don't know what connectors are on your plugin, but milliohm meters typically take a 4 wire probe set. Two wires from each probe tip to individual plugs to the meter. Often a piece of coax, like RG174 is used for the two wires to each tip. You can either buy or make the probes, I made a set for my Polar Toneohm and it works great. Or you can buy them for as much as a few hundred dollars - your choice! Vince - K8ZW. Does anyone have any information on a Tektronix TM500 plugin 067-0699-99? -- Dennis Tillman W7PF TekScopes Moderator
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Vince Vielhaber
While I'm thinking of it, Bob, can you take some pics of that for the
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TekWiki? Thanks! Vince - K8ZW.
Hi Bob,
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bobh@joba.com
Vince and Dennis,
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I'll take some pictures for TekScopes photo area and TekWiki both. I think the Ohms connectors are two conductor and ground small amphenol (?)?? type connectors. Oh yeah, the s/n is B010101, oh boy. Bob.
On 9/5/2019 5:17 PM, Vince Vielhaber wrote:
While I'm thinking of it, Bob, can you take some pics of that for the
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Craig Sawyers <c.sawyers@...>
Does anyone have any information on a Tektronix TM500 plugin 067-0699-99?I think that Tek parts designators that ended in -99 were in-house calibration units. So it is likely you will find it difficult to find a manual, or even the specification. But the point has already been made - take a good series of front panel, and internal shots with the covers off and post them to Tekwiki. Craig
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Daveolla
Greetings, I just received a set of those ebay from China Kelvin clip leads with banana plugs (arrived in Canada from Germany in about 2 weeks) . I just had a look at the gray cable which I had seen RG174 printed on the jacket but just noticed that after that it says "75 ohms" not 50 as would be expected. It should not make any difference that I am aware of at the moment for my 4 wire resistance measurements so it is not a big concern............but your milage may vary, as they say. A blow up of the ebay pic may reveal what is on cable of the various sellers offering the same or similar Kelvin set.
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So curiosity says "sup with dat?" Dave
Hi Bob,
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Steve Hendrix
At 2019-09-06 07:23 AM, you wrote:
That sounds like somebody goofed. Every reference I can find agrees that RG174 is by definition 50 ohms. For DC or low frequency it won't matter much, but if the cable length gets to be more than about 1/10 wavelength, you have to start treating it like a real transmission line, and impedance discontinuities matter. Keep in mind that the propagation velocity in coax is going to be about half that in free space, and for non-sinusoidal signals you have to consider out to about the 10th harmonic (YMMV), so if you're using it e.g. for an LCR meter at 100 KHz, you can get out to a couple hundred feet without problems, but at 1 MHz you're down to a limit of ten feet or so before the impedance mismatch causes problems. Purely speculating here: It could be that somebody with little knowledge of coax saw that it looked like typical TV antenna coax which is 75 ohms, so marked it accordingly without knowing that RG174 is 50 ohms because of its physical dimensions. Impedance matters. I learned that long ago when I was asked to take over network maintenance at my then-employer. A couple of fresh grads had designed the network, with a really goofy layout so lots of long cables. This was thinnet, Ethernet over RG58 coax, which has since mostly fallen out of favor. They mixed RG58U and RG58AU, and it seemed like absolutely every connection was a transition between the two. What's the difference, you ask? About 3 ohms (50 ohms versus 53 ohms), so seemingly insignificant. But all those reflections at every connection added up, making the network very fragile - adding an extra computer *here* would knock somebody off the network *over there*, sometimes clear across the building. Most of those coax runs were on the order of one or two hundred feet total from the server out to the last station. Steve Hendrix
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Daveolla
It does not seem like a goof as it is printed right on the cable RG174 75 ohms SEE ENCLOSED PIC
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If you google RG174 75 ohms you will see it referenced. Here is a sample of the many listings for the Kelvin cable on the bay; https://www.ebay.ca/itm/2x-LCR-Meter-Low-Resistance-Clip-Leads-Banana-Plug-For-Terminal-Kelvin-Test-E-hw/283603350596?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20190717082801%26meid%3D2d3f28ef9cab4f5386ac7d5bf59d44cf%26pid%3D100889%26rk%3D2%26rkt%3D12%26sd%3D202707351110%26itm%3D283603350596%26pmt%3D1%26noa%3D0%26pg%3D2349624&;_trksid=p2349624.c100889.m5204 p
That sounds like somebody goofed. Every reference I can find agrees that RG174 is by definition 50 ohms. For DC or low frequency it won't matter much, but if the cable length gets to be more than about 1/10 wavelength, you have to start treating it like a real transmission line, and impedance discontinuities matter. Keep in mind that the propagation velocity in coax is going to be about half that in free space, and for non-sinusoidal signals you have to consider out to about the 10th harmonic (YMMV), so if you're using it e.g. for an LCR meter at 100 KHz, you can get out to a couple hundred feet without problems, but at 1 MHz you're down to a limit of ten feet or so before the impedance mismatch causes problems.
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Daveolla
Ok, no pic, this is the second try..........this worked before when I posted, if it doesnt go this time try the enlarge feature on the ebay listing (no enlarge when using smartphone but usually the home computer displays it)
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It does not seem like a goof as it is printed right on the cable RG174 75 ohms SEE ENCLOSED PIC If you google RG174 75 ohms you will see it referenced. Here is a sample of the many listings for the Kelvin cable on the bay; https://www.ebay.ca/itm/2x-LCR-Meter-Low-Resistance-Clip-Leads-Banana-Plug-For-Terminal-Kelvin-Test-E-hw/283603350596?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20190717082801%26meid%3D2d3f28ef9cab4f5386ac7d5bf59d44cf%26pid%3D100889%26rk%3D2%26rkt%3D12%26sd%3D202707351110%26itm%3D283603350596%26pmt%3D1%26noa%3D0%26pg%3D2349624&;_trksid=p2349624.c100889.m5204 p
That sounds like somebody goofed. Every reference I can find agrees that RG174 is by definition 50 ohms. For DC or low frequency it won't matter much, but if the cable length gets to be more than about 1/10 wavelength, you have to start treating it like a real transmission line, and impedance discontinuities matter. Keep in mind that the propagation velocity in coax is going to be about half that in free space, and for non-sinusoidal signals you have to consider out to about the 10th harmonic (YMMV), so if you're using it e.g. for an LCR meter at 100 KHz, you can get out to a couple hundred feet without problems, but at 1 MHz you're down to a limit of ten feet or so before the impedance mismatch causes problems.
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Vince Vielhaber
Sorry no quoting, this internet connection and mail program is less than
desirable - I'm remote. RG-174 is definitely 50 ohms. Here's a link to a data sheet on it: https://www.pasternack.jp/images/ProductPDF/RG174A-U.pdf Vince. -- Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/ http://www.metalworkingfun.com -- Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/ http://www.metalworkingfun.com
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bobh@joba.com
These photos aren't good but give you an idea what it looks like especially the front panel and connectors.?? I'll get some better pics later for TekWiki.
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https://groups.io/g/TekScopes/album?id=95106 Bob.
On 9/5/2019 8:30 PM, Craig Sawyers wrote:
Does anyone have any information on a Tektronix TM500 plugin 067-0699-99?I think that Tek parts designators that ended in -99 were in-house calibration units. So it is likely
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Bob Headrick
This is way off topic, but RG-174 is 50 Ohms. RG-179 is a similar size but
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75 Ohms. Folks offering RG-174 as 75 Ohm should probably be avoided.... In this application it does not matter, the instrument in question is DC levels. - Bob W7OV
-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Daveolla Sent: Friday, September 6, 2019 10:03 AM To: TekScopes@groups.io Subject: Re: [TekScopes] TN500 Plugin 067-0699-99 It does not seem like a goof as it is printed right on the cable RG174 75 ohms SEE ENCLOSED PIC If you google RG174 75 ohms you will see it referenced. [snip]
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Dave Casey
Looks like the ohmeter probes are 2-pin Lemo similar to what Tek used in
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other places with more pins. The connectors can still be bought, sometimes at a decent price on eBay, so making up some probes should be pretty easy. Dave Casey
On Fri, Sep 6, 2019 at 2:59 PM bobh@joba.com <bobh@joba.com> wrote:
These photos aren't good but give you an idea what it looks like
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bobh@joba.com
I think you are right about the connectors being Lemo.?? When I get a chance I'll open the plugin up again and look for a number on the base of the connectors.
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Bob.
On 9/6/2019 9:29 PM, Dave Casey wrote:
Looks like the ohmeter probes are 2-pin Lemo similar to what Tek used in
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Dave Casey
You shouldn't need to look too closely. Just measure the OD of the
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connector bezel on the front panel. It should be 10mm, making that a 0S size Lemo jack. The plugs you need to make probes would be part number FFA-0S-302-xxxxx where the last characters (xxxxx) are all related to housing material and strain relief options (so pick what you like from what is readily available). Dave Casey
On Sat, Sep 7, 2019 at 2:03 PM bobh@joba.com <bobh@joba.com> wrote:
I think you are right about the connectors being Lemo.?? When I get a
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bobh@joba.com
How about these?
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https://www.ebay.com/itm/LEMO-S-Series-2-Contact-Connector-Plug-FFA-0S-302-Belden-9452-Cable-16ft-NEW/143193301645?epid=13002506338&;hash=item2156fc628d:g:pt8AAOSw1lxcnvV7 Thanks for sharing your knowledge, saving me a climb up the connector learning curve. Bob.
On 9/7/2019 4:33 PM, Dave Casey wrote:
You shouldn't need to look too closely. Just measure the OD of the
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Dave Casey
Those look right, assuming you measured the connectors on the plugin and
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they jive with the 0S Lemo size. The only other caveat is that Lemo offered both crimp and solder contacts. I've only ever seen solder, but it's possible that those cables were assembled with crimp connectors meaning you'd have a little more trouble moving them over to some RG-174. Of course there's also no reason you couldn't just use the existing cable for your probes; it seems up to the task (shielded, low-Z) and is only marginally bulkier than the commonly used coax. Dave Casey
On Sat, Sep 7, 2019 at 10:19 PM bobh@joba.com <bobh@joba.com> wrote:
How about these?
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Hi Bob,
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That looks like the correct LEMO Connector and the price is excellent. Dennis Tillman W7PF
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of bobh@joba.com Sent: Saturday, September 07, 2019 8:19 PM How about these? https://www.ebay.com/itm/LEMO-S-Series-2-Contact-Connector-Plug-FFA-0S-302-Belden-9452-Cable-16ft-NEW/143193301645?epid=13002506338&;hash=item2156fc628d:g:pt8AAOSw1lxcnvV7 Thanks for sharing your knowledge, saving me a climb up the connector learning curve. Bob. On 9/7/2019 4:33 PM, Dave Casey wrote: You shouldn't need to look too closely. Just measure the OD of the -- Dennis Tillman W7PF TekScopes Moderator
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