Just won a Tek P6046 diff probe at ebay, question on it's psu & accesories - Page 1
Forum section: electronics / testgear

author: BravoV
author_rank: Super Contributor
timestamp: August 21, 2013, 02:40:06 am
content: Finally, after waiting patiently for months, just won at eBay a Tektronix P6046 Differential Probe complete with the amplifier, psu, accesories, box + manual !Attached below the photos originated from the seller, and the probe's psu unit (left box) has a printed label on it "Connected for 115V", the question is, does it support for 220V mains ?To be honest, I'm very exciting since this is my 1st diff probe, appreciate any suggestions or comments on this almost 40 years old probe, although the seller mentioned its working, but frankly I'm not sure on it's accuracy after all this years.Few photo shots on the probe provided by the seller ->Tektronix P6046

author: c4757p
author_rank: Super Contributor
timestamp: August 21, 2013, 03:05:41 am
content: Hmm.... Five minutes, I'll crack open mine and let you know.Yep, here's mine, connected for 120V. Looks like two windings in parallel. I'm sure they can be put in series.Quote from: BravoV on August 21, 2013, 02:40:06 amSay a few prayers to your deity of choice that it's still accurate. Damn thing has more trimmers than Carter's got pills. (Shit, I think I see two right there in thePSU blockthat I never noticed before....)These can also have some funny weird problems that don't always show up, so check it over completely before trusting anything it says. Mine would pick up a parasitic oscillation on just one setting. No idea what caused that - it went away after I pulled it apart, saw nothing wrong and put it back together...

author: JimmyMz
author_rank: Regular Contributor
timestamp: August 21, 2013, 03:13:48 am
content: All I know is that the P6046 supports testing a signal up to 250V with the 10x head and 25V with the 1x head, but I'm not sure if it supports 220V for the actual power supply.

author: BravoV
author_rank: Super Contributor
timestamp: August 21, 2013, 03:51:24 am
content: Quote from: c4757p on August 21, 2013, 03:05:41 amCool ... thanks a lot, really appreciate your helps !Looks like there is a hope with those transformer taps, searching for the service manual now to see if those are mentioned.Again, thanks for the photo.Quote from: c4757p on August 21, 2013, 03:05:41 amDamn, you're starting to scare me now.Yeah, apart from the main reason that I need a differential probe, Jim Williams (RIP) writing also influenced me heavily on buying this almost half century probe.For sure if it's cal is out of whack, then I'm hopeless when it comes to re-calibrate this thing, and have to live with it, btw it cost me < 40 US bucks (excl s/h), not a terrible deal, right ?Quote from: c4757p on August 21, 2013, 03:05:41 amMind elaborate further details ? What weird problems ? Also which setting and/or condition was that on the parasitic oscillation ?Pulled apart on which part ? Probe's body ? Amplifier ? or the PSU unit ?Quote from: JimmyMz on August 21, 2013, 03:13:48 amThanks though, thats the probe's limitation, what I was asking is the mains voltage for the PSU unit for this probe.

author: c4757p
author_rank: Super Contributor
timestamp: August 21, 2013, 04:07:11 am
content: It's not that scary. It's not quite a lump of voodoo and fairy dust requiring $100,000 of equipment to calibrate - just a massive pain in the ass. Dedicate a day or two to it if it needs work.Quote from: BravoV on August 21, 2013, 03:51:24 amExcellent!QuoteThe oscillation, if I remember correctly, was on 20 mV/div, regardless of AC/DC coupling. Close to a sine, >100MHz or so, about half a division ptp. I took apart the amplifier box and it was fixed.I just meant the oscillation itself by "weird problems" - the combination of '60s circuit design, component and connector age and the fact that it's not the most familiar sort of circuit in the world to a lot of people can make it hard to track down issues with it. I still have no idea what caused an oscillation on just one attenuator setting, that control shouldn't have anything to do with the frequency response of the amplifier feedback...I got lucky with the one other problem I had - there was a bad resistor in the probe body, which happened to be exactly the one I checked while stupidly poking around the diagrams trying to figure out where I should look first...Mine hadn't drifted at all since its last calibration in 1989, so if it works I doubt you'll have any trouble. (I'd take apart the probe again to see where the problem resistor was, but I'm not sure I want to go opening it. It was just a mechanical fault - lead snapped - so I doubt there's any reason for you to suspect it will fail there.) The one I had to repair and calibrate was a different one that I got in non-working condition.Just a quick hint/warning if you do end up having to poke around in it, though I'm sure you know: low voltage hadn't been discovered yet in the '60s.... It does have a rail around 100V or so. So don't go licking it or prodding around with sausage-fingers

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 21, 2013, 04:12:59 am
content: I am not sure about this particular probe, but to calibrate Agilent 1141A you only need DC source, DMM, BNC to banana connector and BNC Tee. And I don't bother most of the time cuz for digital signals it does not really matter.One thing you may need is a good 50ohm feed through terminator for your oscilloscope because probe output is 50 ohm and oscilloscope is hi-Z. Without terminator signal on scope won't make any sense.

author: sorin
author_rank: Frequent Contributor
timestamp: August 21, 2013, 06:02:16 am
content: Does anyone have a service manual which include the schematic.

author: BravoV
author_rank: Super Contributor
timestamp: August 22, 2013, 12:14:37 pm
content: c4757p, wow .. what a detail post , thanks !Just read the user manual, confirmed, it supports 230V, only need some re-wiring at the transformer taps exactly like your photo.Quote from: c4757p on August 21, 2013, 04:07:11 amI'm assuming you have some sort of precision signal generator ? If you don't mind explain what you did.Quote from: c4757p on August 21, 2013, 04:07:11 amI guess a tear-down is a must then, looks like its a ritual for every new owner this half century probe.Quote from: c4757p on August 21, 2013, 04:07:11 amDid you calibrate your self ? Any hint for this EE wannabe ?Quote from: c4757p on August 21, 2013, 04:07:11 amNoted, thanks.Quote from: Alexei.Polkhanov on August 21, 2013, 04:12:59 amReally, sounds so simple & easy.But again, this "vintage probe" is not the same league as that modern Agilent 1141A.Quote from: Alexei.Polkhanov on August 21, 2013, 04:12:59 amDon't worry, my Tek 2465B has a built in 50 Ohm mode natively.Quote from: sorin on August 21, 2013, 06:02:16 amWell, I do once I received it, if you see the photos gallery (link at 1st post), there is a photo of the circuit at the included original Tek printed manual. The scanned P6046 documents that are freely available at the internet that I could find so far don't have the schematic.

author: Unknown
author_rank: Unknown
timestamp: August 22, 2013, 01:03:31 pm
content: Quote from: sorin on August 21, 2013, 06:02:16 amNote that there are two different versions (what do you expect if a product is available for decades?) with different manuals. I believe the S/N cutoffs were up to S/N B0199999 for the early version and from version S/N B030100 (or B032108?) for the late version.Two (paid) sources that provide excellent scans:Artek Manuals: both late and early version availableQservice: only late version

author: c4757p
author_rank: Super Contributor
timestamp: August 22, 2013, 01:31:44 pm
content: Quote from: BravoV on August 22, 2013, 12:14:37 pmYoumayhave to find equipment, depending on what you have, or even build equipment. I did. You "need" a square wave generator with rise time under 1ns, which I couldn't find anywhere. I actually built up a variant on the Jim Williams avalanche pulse gen circuit that free_electron was selling, using half a meter or so of coax as the delay line to give a nice, long pulse, and whatever transistor I had on hand that would avalanche reasonably well.You might not really need that, though, I just kind of wanted to build one. The calibration instructions say <1ns rise, but the rise time of the instrument itself is specified as 3.5ns, which you should be able to easily achieve with a fast 7400 logic family like 74AC. Whether that's good enough for calibration would require a careful reading of the instructions, though...You also need a function generator capable of predictable amplitude up to 50 MHz. I usually use my HP 3325A for this sort of thing, but its precision-amplitude output only goes to 20 MHz. The manual doesn't specify how precise the amplitude must be, unless I missed it, but at frequencies over 1 MHz I doubt they're looking for too high an amplitude precision, otherwise you start having to worry about things like insertion loss of the cable too!If you didn't notice, cal instructions are in theinstruction manual here. Some copies of the manual appear to lack them. I found the service manual with schematics back then, but I was stupid enough not to keep it and can't find it again.Looks like it's for sale, according to alm. You shouldn't need them, though, unless you need to do repairs (and most of the "poking around" repairs that I did were done without much reference to the schematics anyway!).As for what I did, beyond gathering equipment, I just followed the directions step by step.

author: Unknown
author_rank: Unknown
timestamp: August 22, 2013, 01:51:16 pm
content: Quote from: Mechatrommer on August 22, 2013, 01:31:15 pmDo you disagree with Jim Williams's statement? How many have you calibrated? Why do you think they made a special calibration shield to provide shielding during calibration? The circuit is extremely sensitive to interference that may show up as differential mode noise. And in general adjusting a large number of interacting trimmers takes forever. Especially with fun statements like 'if these trimmers need more than a little adjustment, go back to step X'.Quote from: c4757p on August 22, 2013, 01:31:44 pmThe Tek PG502, PG503 and PG506 occasionally show up on the used market for affordable prices. All can generate pulses with <= 1 ns rise time. I believe the PG506 was specified in the late version manual. Downside is that they need a TM500 mainframe, and affordable is still going to be more than $40. For good transient response the pulse needs to be clean, that may be tricky in a DIY generator.Quote from: c4757p on August 22, 2013, 01:31:44 pmThe total rise time of the system is the root of the sum of squares of the rise time of the components. So a 3.5 ns square wave through a 3.5 ns probe + scope would show up as a 5 ns signal on the scope. The contribution of a 1 ns to the rise time is negligible, giving an almost 3.5 ns rise time. My guess is that they want the signal to be much faster than the probe.Quote from: c4757p on August 22, 2013, 01:31:44 pmIt's probably only critical for the bandwidth check, for which they suggest a leveled sine generator (doesn't have to be accurate, just constant across the bandwidth). But bandwidth is only a check. If you determine that it only has 80 MHz bandwidth, what are you going to do? In my opinion you can easily skip this step as long as the transient response looks reasonable.

author: c4757p
author_rank: Super Contributor
timestamp: August 22, 2013, 02:21:19 pm
content: Quote from: alm on August 22, 2013, 01:51:16 pmYeah, I'm still keeping my eyes out for one of those, they look pretty useful. Couldn't get my hands on one at the time, though. I was worried about the quality of the pulse too - even f_e's pulse gen has some ugliness - but it seems like mine just wasn't fast enough to set everything into a ringing tantrum. Rise time tested to just under 900ps on a 400 MHz scope, so I guess it must have actually been close to that. I can't remember what I used for an avalanche transistor now, though, it was a while ago.

author: Alexei.Polkhanov
author_rank: Frequent Contributor
timestamp: August 22, 2013, 09:38:03 pm
content: Quote from: BravoV on August 22, 2013, 12:14:37 pm1141A is actually is pretty ancient too. I just followed user/service manual. Have you found a manual for yours? Manual should explain everything in details.

author: BravoV
author_rank: Super Contributor
timestamp: August 23, 2013, 04:41:55 am
content: Quote from: alm on August 22, 2013, 01:03:31 pmModels cut off at S/N B032108 , according to this web site ->The P6046 Differential ProbeInteresting quote from that site ..."Jim Williams claims that the HF sections of this probe are "extrordinarily hard to trim up for CMRR".If he thinks that it's tricky, you know you're really in hot water."About the manual, don't worry, I will have the original printed one complete with the schematic, presumably came originally with the probe from Tek factory.Photos from the seller, quoted from here ->Tektronix P6046 GalleryThe probe is still on it's way, I guess I will have to wait until I received it, finger crossed.

author: BravoV
author_rank: Super Contributor
timestamp: August 24, 2013, 04:04:43 am
content: Quote from: alm on August 22, 2013, 01:03:31 pmAlm, about that the two versions, do you have any link/reference on it ? My Google-fu fails me.Quote from: c4757p on August 21, 2013, 03:05:41 amDid you mean these 4 covered holes at the probe's body ? Just realized it after looking them both closely.From the net, probe body with trimmer holes.While mine doesn't have it.

author: c4757p
author_rank: Super Contributor
timestamp: August 24, 2013, 04:13:37 am
content: No, I meant the ones in the frickin'plug! Damn thing has trimmers in theplug!Aw, shit, your probe doesn't have the cover with adjustment holes? Hopefully it's still good, because you're going to have one hell of a time making adjustments. I suggest cutting and drilling a shield to match. It is very susceptible to noise, you really can't just take off the cover and adjust it that way.But as I said before, if itwasgood, it probablyisgood. It's had a long time to settle between manufacture and whenever the last calibration was, it probably hasn't drifted much since.

author: Unknown
author_rank: Unknown
timestamp: August 24, 2013, 10:00:28 pm
content: Quote from: BravoV on August 24, 2013, 04:04:43 amThis pagebriefly mentions it, and links to a document describing the differences between the manuals, but this link is broken. No functional changes as far as I know, but enough part substitutions to prompt the creation of a new manual, plus a different calibration procedure with newer equipment (PG506/SG503 as opposed to the Tek 1xx series sine / pulse generators).Quote from: BravoV on August 24, 2013, 04:04:43 amThose four trimmers are just four of the trimmers inside the probe. The calibration shield I was referring to has more holes, a picture is posted on the site Ialready linked to. The four trimmers are the ones that might need adjustment within the calibration period of 1 year to maintain its aggressive CMRR specs. A full calibration more trimmers in both the probe and the amplifier. You also need a shielded box with connector for both probe tips, also shown on that page, to feed an identical signal to both tips(note that you're adjusting for 10,000:1 CMRR!). I wouldn't bother with adjustments as long as it performs decently.There are some accessories that might be nice to get. From the factory it shipped with shorting caps across the tips, since the input FET is quite sensitive. You can fabricate something yourself with something like alufoil. It also came with a 10x attenuator that extended its voltage range, at the cost of CMRR. Swivel tips allows you to vary the spacing between the tips. The other accessories are less important in my opinion.

author: BravoV
author_rank: Super Contributor
timestamp: August 25, 2013, 06:52:28 am
content: Quote from: c4757p on August 24, 2013, 04:13:37 amYeah, all I can do is pray now, btw its still on its way though and I might wait for weeks before it arrived.Btw, just found out that yours with those trimmer holes at the probe's body is later revision, mine apparently is the early built. Also at newer revision, the power supply is painted gray, while older one has Tek blu like mine.Quote from: alm on August 24, 2013, 10:00:28 pmYep, that was my problem, but after spending for hours at Tek scopes Yahoo mail-list, reading those "ancient" posts, and with much better & improved Google-Fu, finally I spotted the P6046 manuals revisions document, attached below in this post the document as "P6046CHT.PDF".Quote from: alm on August 24, 2013, 10:00:28 pmAs a hobbyist, I don't have enough tools like a pro, so targeting to adjust it especially that cool CMRR at 10,000:1 is not realistic for me, and also I guess my Tek 2901 time mark generator won't help either, cause its just for scopes horizontal adjustment, am I right ?.Alm, any hint how can I spot if the probe's accuracy or it's CMRR is drifted way too much ? I mean sort of quick and dirty method to verify it ? Fyi, I don't have any wave generator, let alone the precision one.Quote from: alm on August 24, 2013, 10:00:28 pmIf you see the probe's images gallery, I guess it came without all those swivel tips and other standard accessories, only the 10X head.Is it easy to build/fabricate those accessories ? Appreciate if you could share high resolution photos of those for this P6046 probe, and to c4757p too if this is not troubling you too much.Attached below, zipped P6046CHT.PDF , the Tektronix P6046 manuals revisions document.

author: Unknown
author_rank: Unknown
timestamp: August 25, 2013, 02:56:55 pm
content: Quote from: BravoV on August 25, 2013, 06:52:28 amNot for bandwidth or transient response.Quote from: BravoV on August 25, 2013, 06:52:28 amTry the common mode test described in the manual: feed a common signal to both probe tips (try to keep the signal paths the same and grounds short, i.e. use the grounding collar with some wire wrapped around it). Then observe the amplitude of the signal relative to the amplitude you measure in single ended mode (connect only one probe tip to the signal, short the other to its grounding collar). Amplitude is not critical as long as it's stable. Frequency content is somewhat relevant since CMRR is a function of frequency. Non-sinusoidal signals might make the results harder to interpret, although FFT (assuming you're using a DSO) might be helpful. The probe cal signal (for low frequency) and sine waves from the 2901 (high frequencies) might be used as test signals.Quote from: BravoV on August 25, 2013, 06:52:28 amHere is a picture of the swivel tips. Shouldn't be too hard as long as you can devise a reliable way of connecting to the probe tip without introducing excessive inductance (no alligator clips and long leads). A machine pin as used in a high quality DIP socket might work. The manual contains a drawing of each of the accessories, let me know if you need a picture of something specific.

author: BravoV
author_rank: Super Contributor
timestamp: August 26, 2013, 04:18:27 am
content: Alm, really appreciate your great assistances.Quote from: alm on August 25, 2013, 02:56:55 pmDo you mean compare the 2901 (high freq sin) with the reading from the scope when it was attached directly ? Also where to probe (using this P6046), directly at the 2901 BNC output ?Quote from: alm on August 25, 2013, 02:56:55 pmSo that swivel tips are most useful right ? Looks easy enough to build it from machine pins.Its still on it's way, so I mightbugaskyou again once its arrived and had the chance to test it myself.Also I found few photos (attached below) on the net for the accessories, I can see there is a long lead with alligator clip (at 2nd pic), is that the one you mentioned that is useless ? Also 50 Ohm terminator ? I assume thats for scope without 50R termination. Also I'm curious, what is that yellow stick (2nd pic) ?Again, Alm, thanks a lot !

author: Unknown
author_rank: Unknown
timestamp: August 26, 2013, 11:37:38 am
content: Quote from: BravoV on August 26, 2013, 04:18:27 amYou want to feed a signal with a know amplitude (how you measure doesn't really matter) to both probe tips, so it's a common mode signal. It should reject this common mode signal, and the ratio between the amplitude of this signal from the P6046 (taking into account attenuation) and directly measured (with another probe or with the P6046 in single-ended mode) is the CMRR. Ideally you would used the fixture picturedhere, but lacking that, I would probably bring the signal to a PCB with two parallel traces for signal and ground, put the two probe tips on the signal trace and use some improvised ground springs that go around both grounding collars for the ground connection. You want as little as possible difference in length and inductance between the two tips and you want to reduce the loop area between the tips, since that would allow inductive pickup of differential mode signals. Any differential mode signals you pick up will reduce the apparent CMRR, and if you're looking for 10k:1 or 1k:1 CMRR, then even a tiny amount of differential mode signal can swamp the residual common mode signal. You can basically follow the manual for this, you just have to improvise the connections and signal sources. I believe you set the scope to a fairly high sensitivity in AC coupling mode, but check the manual for that.Quote from: BravoV on August 26, 2013, 04:18:27 amThe ground lead is not useless, what I was alluding to was that jumper leads are not a replacement for the swivel tips. You want as little loop area and inductance as possible, so you the length should be say an inch, not a foot.The ground lead is occasionally useful. I believe the official recommendation is try with and without ground lead, and see which works better. It's the same as ground lead for other probes, and not critical for most measurements, which is why I did not list it as important.Haven't seen that yellow thing before, it's not a standard accessory. Probably a trimmer adjust tool of sorts.The P6046 amplifier is designed to drive a 50 ohm load, so you should either enable the internal termination in the scope or use an external terminator (ideally a feed-through model as pictured) to terminate the signal.

author: PA4TIM
author_rank: Super Contributor
timestamp: August 26, 2013, 07:49:40 pm
content: 1 of my 2 complete P4046 sets (I have 3 probes) . One set has a 230V transformer, the other a 115V transformerI just use a 230-110 transformer. That is permanent on my desk because I have more 115V gear.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 26, 2013, 08:20:08 pm
content: may i ask whats the mV/div in the amplifier for P6046 is all about? 1,2,5,20-200 mV/div? let say i'm probing 1V sine source (-ve input to gnd, single ended like setup) what will be the output on the DSO? say if i set the amplifier at 200mV/div, and the DSO at 1V/div?

author: Unknown
author_rank: Unknown
timestamp: August 26, 2013, 08:56:31 pm
content: Quote from: PA4TIM on August 26, 2013, 07:49:40 pmIt's trivial to rewire the transformer for 230 V if you ever feel the need to.The amplifier is designed to work with the scope set to 10 mV/div, this is when the attenuation factors on the amplifier are accurate. The amplifier is only specified for a dynamic range of +/- 100 mV, so going to lower vertical sensitivities of the scope has limited use. Not sure how much higher it goes, not much I suspect. Higher sensitivities are limited by noise. So in general you don't touch the vertical controls of the scope. This also saves you from doing mental arithmetic with attenuation factors.The output from a 1Vp-p sine at 200 mV/div will be a 50 mVp-p sine, so setting the scope to 1 V/div will result in a very compressed sine.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 26, 2013, 09:43:59 pm
content: Quote from: alm on August 26, 2013, 08:56:31 pmi'm not sure i understandQuote from: alm on August 26, 2013, 08:56:31 pmi'm not sure i understand sorryQuote from: alm on August 26, 2013, 08:56:31 pmi'm trying to get mental arithmetic for this... so from what i gather in your post... if i set the amplifier at X (mV/div,) the probe output will be Y (Vp-p) sine? please confirm if i have mistake (below)...X, Y1, 102, 55, 210, 120, 0.550, 0.2100, 0.1200, 50m?

author: c4757p
author_rank: Super Contributor
timestamp: August 26, 2013, 10:02:07 pm
content: It doesn't matter. The point is that you don't have to care. Set the scope to 10mV/div and leave it alone. Then, the true vertical scale as seen by the probe tip is read out on the P6046 attenuator dial. If the scope is set to 10mV/div like it should be, and the P6046 attenuator is set to 200mV/div, then the waveform display is 200mV/div.

author: Mechatrommer
author_rank: Super Contributor
timestamp: August 26, 2013, 10:50:46 pm
content: so its overriding the dso vertical scale? ok i got it (i hope), carry on guys

author: BravoV
author_rank: Super Contributor
timestamp: September 15, 2013, 10:35:07 am
content: Just a brief update, it arrived with the condition as seller claimed, and looks like the previous owner didn't use it too often and almost no scratch at all on the probe, attenuator, amplifier and the psu.Thanks a lot to our fellow in this forum Corporate666 for his generosity, as he was acting as my proxy bidder at ebay, and also helped me in sending it to me.The only accessories apart from the probe,amplifier and the psu, are only some blue plastic pieces that is still in sealed plastic bag (check below photo "03. Whole Package & Accesories.jpg"), not sure what its used for, and of course the most important accessory is the 10X attenuator head.Just an advice to other if you're planning to buy this probe, imo this piece of attenuator is really important, just don't buy it or bargain for dirt cheap price if the package doesn't come with it, beware.Overall, I'm content looking at the physical condition especially its still looks quite new after almost half century, also it includes the original printed manual.Now the hardest part, finding a spare time.... sighThings to do are :- Tear it down and do an internal inspection at this 50 years old gadget.- Changing the transformer taps from 110V to 230V.- Finally, the scariest part, powering it up and test it if its working as it should, fingers crossed.- DIY for those missing important/crucial accessories.Few photos attached below freshly captured when I unpacked it.Any comments or suggestions regarding it's current condition are welcome.

author: Unknown
author_rank: Unknown
timestamp: September 15, 2013, 11:06:21 am
content: I would probably keep the attenuator tip on until you've fashioned some sort of shorting caps. That should give atleast some ESD protection. The input FET is quite sensitive, more so than single-ended FET probes, since any ESD protection diode or resistor would degrade the CMRR. And of course Tek in their infinite wisdom decided to use polystyrene packaging.The blue accessories are for mounting the amplifier on the side of your scope. Probably not that useful these days with all the Playmobil scopes, but I guess it was useful back when service were still lugging Tek 453s as carry-on luggage to customer sites.Condition looks fine. Don't forget to change the fuse when you change the voltage taps. At least they didn't use the terrible trick they used for the 134 where they put a resistor in series with an overheating 110 V transformer.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 15, 2013, 11:36:33 am
content: I had such a mount also with the probes but I mounted it to my 547. It hold the 131 current probe amplifier.about changing the powersupply to 230V. This is npot so easy as it sounds because it has a USA connector and that is not easy to swap for a dutch plug. But I have a 230-110V transformer on my bench so I do not care about 110V psu's

author: Unknown
author_rank: Unknown
timestamp: September 16, 2013, 12:12:22 am
content: Convert it to 230 V, put a big label on it, and use a travel adapter to plug it into your local mains socket. Of course there's nothing wrong with using it at 110 V if you have that available.

author: BravoV
author_rank: Super Contributor
timestamp: September 16, 2013, 04:06:06 am
content: Quote from: alm on September 15, 2013, 11:06:21 amShorting caps ? How ? Please elaborate further, and I'm assuming shorting from the tip to the ground right ?Yeah, I kinda curious about using that polystyrene too, especially when you pull out the probe or the attenuator from it, cause they're snugly fit and the plastic part rubbing those polystyrene may create static too right ?Quote from: alm on September 15, 2013, 11:06:21 amThanks & noted.Quote from: PA4TIM on September 15, 2013, 11:36:33 amFor me its not a big deal, an US to schuko adapter should solve this problem.Fred, btw I noticed you love photography and also you have 3 sets of this probe, would you do me a big favor if you have time for it, please ?What I need is, take a clean white A4 paper, place all those P6046 accessories on it, and take a macro close up shot on them, again, please.I strongly believe you must have those cool macro lenses right ?I'm interested at those swivel tips that I'm going to fabricate them my self, especially on it's rear on how they constructed it, really appreciate if you could take a close up shot on the rear and the front (the tip). Or other parts as well if you think they have other details that I need to know or aware of.Apart from Fred (PA4TIM), appreciate if any one of you willing to help me on this too. Calling out c4757p ...Quote from: alm on September 16, 2013, 12:12:22 amNo need for the label, see that metal plated with the printed "Connected For 115 V" ?It has both sides printed, one for 115V and the other side is printed "Connected For 230 V", nice isn't it ?

author: Unknown
author_rank: Unknown
timestamp: September 16, 2013, 05:22:24 am
content: Quote from: BravoV on September 16, 2013, 04:06:06 amYep, just short the probe tip to the grounding sleeve. To quote myself from earlier in this thread:Quote from: alm on August 24, 2013, 10:00:28 pmQuote from: BravoV on September 16, 2013, 04:06:06 amI attached some pictures, let me know if you need more. I included one of each of the accessories, but I figured you knew what a ground lead, a BNC cable and a terminator looks like. You should be able to identify them from drawings in the manual.The close-ups are the tip of the swivel tip, the probe socket part of the swivel tip, the socket part of the hooks (which is fairly similar to the swivel tip and could be converted in one) and the inside of a shorting cap. The shorting cap consists of two strips of springy metal that contact the grounding sleeve and meet at the tip. The tip would go through the slit between the two strips that you can barely see in this picture.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 16, 2013, 11:52:34 am
content: teardown of the attenuators will be nice.

author: BravoV
author_rank: Super Contributor
timestamp: September 17, 2013, 04:32:45 am
content: Quote from: alm on September 16, 2013, 05:22:24 amAlm, thank you so much, really appreciate the effort taking those photo shoots.I just noticed after all this time that my grounding sleeve at the probe and at attenuator are gold coated, while yours and like many others that I've seen at the net are not. I guess mine must be from pretty early version and it must be really-really old, probably it was made when gold price was still cheap eh ?As you suggested, I already wrapped the probe tips with alu foil from the sleeve up to the tip. Btw, the attenuator doesn't have any sensitive JFET in it right ?What is that yellow metal thing in the middle , the black cap below the grey shorting cap used for ? and also the silvery bnc connector like that in the plastic bag ? Is that for custom diy tip ?Quote from: alm on September 16, 2013, 05:22:24 amIts clear now, the connector part at the swivel tip and also at the hook tip don't have any contact to the ground sleeve, just a single contact for at the probe tip, so its not shielded. Thanks again, this what I was really curious at from the start. Did an increase at the photo exposure to see the darker part inside here.So what are those black caps that those I have are used for ? Especially with the exposed tiny part of the tip ? The manual really doesn't tell much about the detail usage for those accessories.

author: BravoV
author_rank: Super Contributor
timestamp: September 17, 2013, 04:38:22 am
content: Quote from: Mechatrommer on September 16, 2013, 11:52:34 amYes, thats the plan, but design wise, I don't think it will compatible with your HP probe.You should ask Alexei.Polkhanov to post his 1141A atten head since you both have the same identical probe right ?

author: Unknown
author_rank: Unknown
timestamp: September 17, 2013, 07:30:41 am
content: Quote from: BravoV on September 17, 2013, 04:32:45 amI haven't seen a schematic or opened mine up, but since the thing has no power supply, I consider it highly unlikely. Probably just a compensated voltage divider with a passive compensation network and some extra attention paid to matching the two channels. The CMRR with attenuator is specified as 'only' 1000:1, but that still requires better than 0.1% matching of the attenuation ratio across the bandwidth of the probe.Quote from: BravoV on September 17, 2013, 04:32:45 amThe manual calls the gold-colored one a spring ground clip. It clips on the ground sleeve, somewhat similar to the low-inductance ground springs you have with single-ended passive probes. The connector in the plastic bag is what the manual calls test jack, a coaxial socket that fits one of the probe tips and that can be used to provide a coaxial connection to some custom circuit.Quote from: BravoV on September 17, 2013, 04:32:45 amThe black ones (in my picture) just insulate the ground sleeve to prevent it from touching anything in the circuit. The ones that are dark gray in my picture are IC insulator tips that are designed for probing DIP ICs (or anything with similar lead spacing): it prevents the tip from shorting two adjacent pins and stabilizes it when probing DIP ICs.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 17, 2013, 11:24:23 am
content: Quote from: BravoV on September 17, 2013, 04:38:22 ami dont care, teardown of an attenuator of any kind will always be fun.

author: BravoV
author_rank: Super Contributor
timestamp: September 17, 2013, 12:20:16 pm
content: Quote from: alm on September 17, 2013, 07:30:41 amBtw, does the 1000:1 performance at this vintage probe is still considered a decent performer compared to modern probe with comparable bandwidth ?Quote from: alm on September 17, 2013, 07:30:41 amThis connector will be handy, do you know what the common name for that connector ? or the part no equivalent at other brand ? If its cheap, it will be handy to have few spare of those.Another macro shoot on this connector at front & end will be appreciated if its not troubling you too much.Quote from: alm on September 17, 2013, 07:30:41 amThats it, I was thinking so hard why the heck they made this caps for ? Now you've answered it clearly.Again, thanks for the prompt responses Alm.

author: Unknown
author_rank: Unknown
timestamp: September 17, 2013, 02:58:50 pm
content: Yes, this is decent performance. Compare for example theTek P6246: 60 dB (1000:1) CMRR at 1 MHz, 38 dB (~100:1) at 100 MHz. Or theAgilent 1141A: 3000:1 CMRR at 1 MHz and 10:1 at 100 MHz.I don't know of a good source for the probe socket,Qservice has one available, but not cheap.

author: linux-works
author_rank: Super Contributor
timestamp: March 25, 2014, 10:25:13 pm
content: bravo forced me to buy one of these, too (lol)picked mine up today and it was complete (all but the ground lead). the atten module was there and the accessory bits, too.http://www.ebay.com/itm/171062974196it was sort of local to me and I got the seller to allow me a little bit of testing time (at home) and return privs if it did not work. it does seem to work, though, so I might be happy with it.the atten attachment distorts the wave, though. seems like it needs adjusting.I think I figured out what the yellow stick thing is. mine didn't come with it (damn) and its needed to adjust the atten head 'screws'. they are not slotted or philips but look like tiny square cutouts, and so a regular tuning stick won't do it, here.if you have that yellow stick, consider yourself lucky. most don't seem to come with it, used. why can't owners be more responsible?yeah, I know, its companies that don't care about their own things; OWNERS usually take great pride in their toys.

author: BravoV
author_rank: Super Contributor
timestamp: March 26, 2014, 02:29:23 am
content: I guess I'm pretty darn good at convincing and with above average on the persuasive skill, right ?When it comes to adjustment, this little beast even scared the hell out of Jim Williams (RIP), it is wise to approach this matter with great cautions if you decided that you have itchy fingers to turn some trimmers in there.

author: linux-works
author_rank: Super Contributor
timestamp: March 26, 2014, 08:26:00 pm
content: this particular unit used to have an ATT leasing sticker on it. the US phone company, so to speak, ATT also has lots of business units and I've seen the ATT leasing sticker on surplus stuff before. and so, since this was a loan-for-fee kind of unit, I bet the owner removed the tuning tool to prevent customers from messing things up. sadly, the tool was never restored to the unit when it was retired. THIS new owner would have liked to have it

author: Neganur
author_rank: Unknown
timestamp: April 06, 2014, 02:28:05 am
content: BravoV, I'm selling all my scope gear and happen to have a P6046 with most accessories that I want to get rid of.The power supply is set to 230V and the power rails seem OK but not great (+50.1V, -50,1V, +20.56V, -6.27V) especially the -6.2V seems to oscillate at times. Maybe the wet tantalum caps are out of spec. The amplifier itself seems to have an issue too, since atten bal knob doesn't bring the trace within 1 div in all the mVolts/div settings. I can't get the probe to show a signal except for in the 20 mVolts/div setting. Quite frankly I cba to troubleshoot it, I don't have the time.You can have it for shipping cost if you want. It has the box, two 10x attenuator heads, the probe has the adjustment holes, 4 swivel heads, the shorting heads and lots of other stuff.

author: BravoV
author_rank: Super Contributor
timestamp: April 06, 2014, 08:49:10 am
content: Wow, thank you Sir !PM to follow.

author: David Hess
author_rank: Super Contributor
timestamp: April 06, 2014, 01:36:53 pm
content: Quote from: BravoV on September 17, 2013, 12:20:16 pmIt is more like 500:1 at 50 MHz but that is still cutting edge performance. 500:1 is 54 dB. Good high voltage differential probes are only 30 dB at 50 MHz and the best ones are only about 45dB. The best low voltage differential probes I could find only match the P6046 at about 55 dB at 50 MHz but have much higher bandwidths.The P6046 was in production for a long time.

author: BravoV
author_rank: Super Contributor
timestamp: April 06, 2014, 02:41:21 pm
content: Quote from: David Hess on April 06, 2014, 01:36:53 pmDavid, thanks, its good to know that even a 50 years old design still can stand through time.Yeah, it was introduced in late 60's and was still actively produced and sold until in 90's, and by surviving for 30 years actively produced at Tek factory, I guess its a very well & proven design.Besides we all know that Tektronix released tons of new T&M designs & products during the period of 60's to 90's, and if there was a better design, pretty sure Tek will release it's successor, instead of they didn't touch this particular product for decades, cmiiw.One thing for sure, this beast was not cheap even back there, according to this reference ->Tektronix P6046 history, in 1969 it's price was $725, and translated with inflation calculator into 2014 is about $4,638 in today's money, damn !

author: linux-works
author_rank: Super Contributor
timestamp: April 08, 2014, 12:43:51 am
content: scored a 'rarity' option for this probe:not cheap but it looks like its in great condition.

author: BravoV
author_rank: Super Contributor
timestamp: April 08, 2014, 03:10:58 am
content: Wow, really nice score, congratulation ! A rarity indeed !Damn, I'm now so jealous.

author: linux-works
author_rank: Super Contributor
timestamp: April 08, 2014, 03:16:46 am
content: $50 for a metal box, a bnc and 2 funky tek-femalesbut it came up in a search and was quite unexpected.I wonder if the ground is connected to scope ground? I think the grounds on the probe sleeves are connected to a bus, then one of the diff center wires is connected there and that becomes the bnc shield. the bnc center is the other probe's center pin.but I'm not sure if the shield around each of the diff probe points is equal to scope ground. I guess I can buzz it out and see...

author: BravoV
author_rank: Super Contributor
timestamp: April 08, 2014, 03:22:09 am
content: Well, suggesting RTFM thoroughly 1st. Personally I just can not afford to assume too much when it comes to the finicky of calibrating/tuning this 50 yrs old beast, remember, it even scared the hell out of Jim Williams (RIP).

author: linux-works
author_rank: Super Contributor
timestamp: April 08, 2014, 03:30:28 am
content: I'm not sure its just for calibration. if it can be used as a fet low-z input probe with a lifted ground, then that's a good enough use for this metal can thingif its at scope ground, then its no longer floating but its still a low-z fet input, which can be useful.

author: Behemot
author_rank: Contributor
timestamp: August 07, 2016, 01:50:35 am
content: Hey BravoV, have you been able to rewire the PSU for 230 V? I am just shopping for a set on fleebay which a collegue of mine will than take here from the US. (Shipping to Europe costs usually almost as the set itself) After it gets here I could also use a direct 230V input instead off using transformer ;-)

author: BravoV
author_rank: Super Contributor
timestamp: August 15, 2016, 03:58:52 am
content: Quote from: Behemot on August 07, 2016, 01:50:35 amSorry, missed your post.Short answer : Yes, no need to get an extra step down transformer, it works flawlessly after rewiring.Just follow exactly as the manual stated, of course read carefully, always check and re-check after you rewired, before plug it into the mains outlet.One small nice details, see the little label metal plate that says "CONNECTED FOR 115 V" with two screws holding it ?Just unscrew the plate, flip it, as the other side has "CONNECTED FOR 230 V" printed on it, nice isn't it ?

author: Behemot
author_rank: Contributor
timestamp: October 10, 2016, 07:44:34 pm
content: Yeah I actually was pointed to the schematics, with it it was very easy to rewire. Already turned the label around, I thought it will be blank so I'll write it to the other side, and there was the 230V textAlready also ordered some measurement clips as for the kind of thing I measure, the probe tips are useless. Ordinary passive probes with those "hooks" they come with are ideal for me. Till I make a new load tester at least which would already be designed for the probe tips…Anyway, I think I'll have many questions for using the probe. Lets start right away. I always thought that the less mV/div, the more "zoomed in" the waveform will be. That's how the O-scope knobs work at least. Here it seems to be the opposite, I have to increase the mV/div value on the amplifier to get closer view. Am I missing something?

author: JPortici
author_rank: Super Contributor
timestamp: June 15, 2017, 11:17:52 am
content: Hi! I recently won a p6046 from the US.Flippable plate is a nice touch.Anyway, this should be correct, right? Shematic says bridge between 2 and 3 instead of 1 to 2 and 3 to 4I have three more questions:- do i need to connect the earth terminal? I don't have an US to IT/SHUCKO adapter with earth at the moment-can i change the plug? Though the power supply is bulky, i'd rather build an adapter cable-if i wanted to probe between two points at an arbitrary distance... what are the two wire thingie that you can plug on the tip called? Where can i find them?

author: BravoV
author_rank: Super Contributor
timestamp: June 20, 2017, 07:46:25 am
content: JPortici, congratz on the score !Quote from: JPortici on June 15, 2017, 11:17:52 amThough I don't remember the detail now, I did the rewiring from 110V to 230V "exactly" as the manual instructed, of course, check, recheck ... and recheck again, and it just work.Quote from: JPortici on June 15, 2017, 11:17:52 amNot sure, but I do use US plug to Schucko adapter that has the ground terminal, something that looks like this. (from Google)Quote from: JPortici on June 15, 2017, 11:17:52 amIf you managed to replace it, please, update us, I'm interested too.Quote from: JPortici on June 15, 2017, 11:17:52 amMy probe also missing those tiny accessories, I used small solid copper wires, spun/coil at the drill bit that has the same diameter as those tiny sharp tips, and then attached the coiled copper wire snugly at both tips (also it can be detached), and then soldered the other wires end at the test points.A ghetto mod, but it works.

author: JPortici
author_rank: Super Contributor
timestamp: June 20, 2017, 08:08:17 am
content: i haven't had a moment to try it yetit's here at the bench at work but no occasion to do soand i was away for the weekendand i'm going away this weekend again

author: Behemot
author_rank: Contributor
timestamp: June 20, 2017, 12:00:41 pm
content: Me neither. Also did not get all the equipment so I bought some small clips etc. to play with it further somewhere in future as I was also getting some strange readings (almost no output signal etc.). It's laying on the bench ever since