Date
1 - 17 of 17
Replacing cable on P6075A probe
I have a P6075A that appears to have a break in the middle of the coax cable, and I also have a replacement cable assembly.
How difficult is the process of replacing the cable on one of these probes? Does anybody have instructions on how to do such a thing? Thanks -- Jeff Dutky
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Colin Herbert
Jeff, take a look in TekWiki for the manual for the P6075A probe.
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http://w140.com/tekwiki/wiki/P6075 It gives details of cable replacement. If you are not already aware, TekWiki is nearly always the first place to look, though sometimes it won't have what you want - in this case it does. Colin.
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jeff Dutky Sent: 16 November 2020 18:27 To: TekScopes@groups.io Subject: [TekScopes] Replacing cable on P6075A probe I have a P6075A that appears to have a break in the middle of the coax cable, and I also have a replacement cable assembly. How difficult is the process of replacing the cable on one of these probes? Does anybody have instructions on how to do such a thing? Thanks -- Jeff Dutky
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Brent W8XG
Jeff, your probe is a 200mhz unit. I re-cabled a p6062 which is a 100mhz. However they appear similar and I expect are built about the same.
I had a break. I cut the cable at both ends. There is a strain relief fitting, and I used a small Dremel drill to remove the extra material. Then I went to work on the cable. The probe wire is the finest, smallest wire I've ever see. It took some time and was quite tedious. But I got it done. It was a couple of hours. Also, mine is a 1x/10x switchable probe. There is a very fine wire (not as fine as the probe) on the outside of the coax, to the switch, that switches in/out the 11K resistor, to the scope changing to the correct vertical display. Your probe has the readout pin on the bnc connector. It goes to that 11k resistor so the scope switches vertical values. I've got another probe also with a readout pin, but apparently the wire to the resistor, or the switch is broken, so the scope doesn't switch. I've also got several probes without the readout pin. So, I put together a little washer looking device that I've called a TekRing, that slips onto the BNC to tell the scope what value your probe is. It spoofs the scope to the right value. I've got a little website http://tekring.net/ that discusses this. Good luck.. You need a good set of magnifying glass, to see that little wire. But it's worth fixing, in my opinion.
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On Mon, Nov 16, 2020 at 02:07 PM, Brent W8XG wrote:
I had a break. I cut the cable at both ends. There is a strain relief fitting, and I used a small Dremel drill toBrent, did you also make a YouTube video about the process? I believe I watched such a video when I was first considering doing this; it was daunting, but encouraging. I have what appears to be a complete kit for replacement of the cable, and it looks relatively straightforward (except for the bit about soldering a wire that is thinner than a human hair!), but I have several questions about the process: 1. The compensation box end of the cable has a significant extra length of insulated cable (about 2cm in excess of what is necessary) and I don't have any special tools to cut and strip the insulation from a coaxial cable of this small diameter (or any coaxial cable for that matter, but I can easily strip regular RG58 with an Xacto knife). How would you suggest stripping the insulation off the extra length of cable? 2. There is an extra part in the kit, a tiny grommet about 2mm long and 2mm in diameter at the flanged end. The instructions do not mention this grommet at all, and I don't see anything similar to it in the existing probe. Is this something that is needed for some probes (but not, presumably, for my P6075A)? 3. I checked the resistance of the new cable and the damaged cable, both read about 250 Ohms. This is a bit lower than I expected. Does this sound correct? I will try to upload pictures of the kit to the photos section under an album titled "P6075A Replacement Cable"
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Brent W8XG
No, I did not do a YouTube video. But I've seen one out there. I didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.
So my cable is now a little shorter. The 250 ohm's is likely about right given the size of the wire, but I didn't measure it. So my cable might be 200 ohm's now. But with the 9k resistor in there to make it a 10x probe, I doubt it matters much. I don't know what the grommet is for. Maybe it's to slip over the cable and then crimp to become strain relief?? Regards,
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Tom Lee
Not quite right to compare 250 to 10Meg and declare 200 to be therefore ok. By that logic, zero ohms should be just fine, too. Yet, Tek went to the trouble to use resistance wire. Clearly there's a reason!
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The purpose of the resistance wire is to damp out reflections due to mismatch. There's a Goldilocks optimum for each length that balances bandwidth against aberrations. If you deviate from that balance, either parameter degrades. That said, you're probably not going to notice any dramatic change. But if you had before and after measurements, you'd see a difference. Tom Sent from my iThing, so please excuse the terseness and typos
On Nov 17, 2020, at 5:24, "Brent W8XG" <brent@pwg.net> wrote:
No, I did not do a YouTube video. But I've seen one out there. I didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.
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Daveolla
Greeting, Also, take note of what the manual says about shortening the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A version from the links given earlier in this thread;
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http://w140.com/tekwiki/wiki/P6075 It is also repeated (or vise versa) in the plain P6075 manual on page 5 at the same link. It states; "Substitution of non-standard parts is not advisable if the original performance is to be restored. Even shortening the cable by more than a few percent will have a noticeable effect on the transient response of the probe. The resistive center conductor has been specifically selected for critical dampening of reflections that would otherwise exist." And then is the "Conector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box." They dont tell you how to do that though. Perhaps the plastic has stiffened somewhat suggesting you need a good pry from a screwdriver. Perhaps a blade edge of knife gently if a finger nail wont budge it. It can also be stuck and needs to be cracked loose. If you nick or dint then you gotta fix that somehow........or I do. Leave no marks is the goal. Im sure we have all seen somones attempt at opening stuff up, TVs, phones, etc that looked like a jackhammer attacked it everywhere. Use a screwdriver for what it was intended, prying open paint cans!!! On a side note, what is the difference in the plain P6075 and the A version? I see the specs for the plain versions input impedance is 10meg within 0.4% and 0.5% for the A. Dave
At 07:51 AM 11/17/2020, you wrote:
Not quite right to compare 250 to 10Meg and declare 200 to be therefore ok. By that logic, zero ohms should be just fine, too. Yet, Tek went to the trouble to use resistance wire. Clearly there's a reason!
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Jim Ford
Or use one of those handy metal thingies from Home Depot to open paint cans if you're here in the States. Doubles as a bottle opener so you can have a cold one while you paint! Don't blame me if your paint job doesn't come out so great, though. ;)
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Jim Ford
------ Original Message ------
From: "Daveolla" <grobbins@netflash.net> To: TekScopes@groups.io Sent: 11/17/2020 9:44:13 AM Subject: Re: [TekScopes] Replacing cable on P6075A probe Greeting, Also, take note of what the manual says about shortening the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A version from the links given earlier in this thread;
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Daveolla
Ya, I have a handy jar with about 5 or 6 of those paint openers, 2 styles. They work real good. They could make screwdrivers obsolete! Now if they had a gizmo to put the lid back on the paint can it might obsolete hammers.. Once the lid pounding dents the side of the can, the lid never goes back on well, too much springiness or bounce in the lid rim.
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Dave
At 10:53 AM 11/17/2020, you wrote:
Or use one of those handy metal thingies from Home Depot to open paint cans if you're here in the States. Doubles as a bottle opener so you can have a cold one while you paint! Don't blame me if your paint job doesn't come out so great, though. ;)
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Colin Herbert
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-----Original Message-----Daveolla Sent: 17 November 2020 17:44 Greeting, Also, take note of what the manual says about shortening http://w140.com/tekwiki/wiki/P6075 It is also repeated (or vise versa) in the plain P6075 manual on page "Substitution of non-standard parts is not advisable if the originalexist." And then is the "Conector Replacement" next with step 1 as "Remove Im sure we have all seen somones attempt at opening stuff up, TVs,So why is it called a screwdriver and not a paintcanpryer? Sorry, but I can be a bit funny about the misuse of tools - I hope you were joking, here. On a side note, what is the difference in the plain P6075 and the A DaveAt 07:51 AM 11/17/2020, you wrote: Not quite right to compare 250 to 10Meg and declare 200 to bereason!
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Colin Herbert
Try just putting the can with the lid in the right place on a solid flor and
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stand on it. If it goes right the lid is on securely, if not you have some nice new different-coloured shoes.
-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Daveolla Sent: 17 November 2020 18:14 To: TekScopes@groups.io Subject: Re: [TekScopes] Replacing cable on P6075A probe Ya, I have a handy jar with about 5 or 6 of those paint openers, 2 styles. They work real good. They could make screwdrivers obsolete! Now if they had a gizmo to put the lid back on the paint can it might obsolete hammers.. Once the lid pounding dents the side of the can, the lid never goes back on well, too much springiness or bounce in the lid rim. Dave At 10:53 AM 11/17/2020, you wrote: Or use one of those handy metal thingies from Home Depot to open
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Daveolla
On my probe, the wire broke off right at the connection so soldering it back on only shortened it by less than an 1/8", I thought nothing of the loss, though I did not have the manuals caution to ponder at the time. Mine broke from the connector turning on the compensation box. Make sure it is good and tight and check others probes incase they have loosened in time.
Mine is the non A version, with a cable that has stiffened somewhat with age, not too bad, I have some older Tek probes that are unuseably stiff. Dave
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Ray
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Beware of spitting cans, when hammering on the lid. :))RaySent from my T-Mobile 4G LTE device------ Original message------From: DaveollaDate: Tue, Nov 17, 2020 11:15To: TekScopes@groups.io;Cc: Subject:Re: [TekScopes] Replacing cable on P6075A probeYa, I have a handy jar with about 5 or 6 of those paint openers, 2
styles. They work real good. They could make screwdrivers obsolete! Now if they had a gizmo to put the lid back on the paint can it might obsolete hammers.. Once the lid pounding dents the side of the can, the lid never goes back on well, too much springiness or bounce in the lid rim. Dave At 10:53 AM 11/17/2020, you wrote: Or use one of those handy metal thingies from Home Depot to open
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n4buq
I don't hammer them anymore and find that merely pressing the lid with my hands or thumbs seats the lid well enough. Besides, a lot of the modern paint "cans" are plastic with a metal rim and lid. They hammer them at the big box stores but I still shy away from that.
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Thanks, Barry - N4BUQ
----- Original Message -----
From: "Colin Herbert via groups.io" <colingherbert=blueyonder.co.uk@groups.io>
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Geoffrey Thomas
A length of wood across the lid to spread the load whilst hammering, moving around the circumference while so doing, then inverting the can to let the remaining paint seal any micro holes to stop the solvent evaporating.
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Shirley? Geoff.
On 17/11/2020 18:56, n4buq wrote:
I don't hammer them anymore and find that merely pressing the lid with my hands or thumbs seats the lid well enough. Besides, a lot of the modern paint "cans" are plastic with a metal rim and lid. They hammer them at the big box stores but I still shy away from that.
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John Gord
Dave,
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I think the main difference between the P6075 and P6075A was the ground lead attachment method. On the P6075 the lead screwed into a hole in the side of the probe. In the P6075A it attaches with the forked pincher into a groove on the probe (like most of the later probes of that general size). --John Gord
On Tue, Nov 17, 2020 at 08:44 AM, Daveolla wrote:
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Daveolla wrote:
And then is the "Connector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box."The probe and scope belonged to my father, he was the one who discovered that the probe was bad, I have merely verified the fact. He opened the compensation box himself, so I have no trouble getting it open now. I'm not sure what my father had to do to open the box, but I have used a nylon "spudger" to open it in order to minimize marring the surfaces.
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