Should I sell my Tek current probe and put $$ towards a Rigol DS1054 - Page 1
Forum section: electronics / testgear

author: echap
author_rank: Contributor
timestamp: November 11, 2015, 05:35:23 pm
content: I bought a Tek 475 scope a couple weeks ago on ebay and then found this forum. Wish I had found it sooner. Anyway, the Tek scope came with a bunch of probes and one of them was the P6021 current probe and terminator. It's in nice shape. I am thinking that the Rigol scope is what I should have bought.I am thinking that at the price of these current probes on ebay, perhaps I should sell it and put the money towards a Rigol scope. I really don't know that I will use the current probe much and might just as well peddle it off.What do you guys think?

author: Rupunzell
author_rank: Frequent Contributor
timestamp: November 11, 2015, 05:52:58 pm
content: A GOOD current probe is one of the most useful probes for any time domain instrument. It might be of low apparent value to you now due to a lack of understanding of how to use and what to use it for. In time, that may change dramatically and that current problem will be a measurement saver.FYI, the normal test set up is two voltage probes, one voltage differential probe and one current probe.Good probes are the most valuable accessory to a time domain instrument. Depending on measurement needs adding a DSO could be of lesser value than believed. Low quality, high distortion, poor durability probes are the source of immense measurement grief.There is a steep learning curve with a analog scope such as a 475. Operating it is just one challenge, the far greater challenge is learning how to interpret, deeply understanding the display wave form. This is no different than learning a foreign language. It requires much study, effort, concentration, making errors and more. Extremely intimidating for anyone at the start. What the modern DSO does offer is similar to automated language translation where the time domain display is automatically interpreted for you into a very familiar language that is easy to understand and it is also stored in memory for easy recall. Information can be lost or altered during the translation with the deeper meaning dropped and disregarded post translation.This could be why there is regret in purchasing the Tek 475 vs any modern DSO.Bernice

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: November 11, 2015, 06:03:05 pm
content: Yeah, but the P6021 is AC only, isn't it? A DC/AC probe is much more useful (and expensive)...

author: Rupunzell
author_rank: Frequent Contributor
timestamp: November 11, 2015, 06:30:13 pm
content: DC current probes are not alway more useful than AC only current probes. It is dependent on the specific measurement required. Really useful DC current probes will have less than 1mA per 50mV or similar sensitivity, low noise, DC low drift and enough AC bandwidth (greater than 50Mhz) to be truly useful. If the AC content of the measurement is small relative to the DC current bias, it could over load the DC coupled current probe for a given range setting. Where the AC coupled current probe would be more tolerant of this measurement condition as long as the current probe core is not driven into or near saturation.The common idea for using a DC current probe is measuring DC power, it is also useful for very low frequency current measurements (typically below 10Hz).For the vast majority of circuit current probe measurements a good AC current probe is fine. Don't be deceived by more features is always better or preferred, better is a high quality probe that is accurate, reliable and durable.. with a caution. All current probes are fragile by nature. They are and can be easily abuse resulting a host of problems.Once all these factors are considered for a DC/AC current probe, it is no longer a low cost item.BerniceQuote from: 0xdeadbeef on November 11, 2015, 06:03:05 pm

author: I4E
author_rank: Regular Contributor
timestamp: November 11, 2015, 06:38:35 pm
content: Some of the Tek probes work with the Rigol scopes so I wouldn't get rid of it.Joy TorresInstruments 4 Engineers Ltd

author: saelig
author_rank: Contributor
timestamp: November 11, 2015, 06:57:52 pm
content: We looked up that probe model: Your current probe should work fine with a 1054A! Hang on to it! And PM me for a discount on a new DS1054Z.Alan Lowne CEO Saelig Co. Inc.

author: Deathwish
author_rank: Unknown
timestamp: November 11, 2015, 07:10:22 pm
content: I would certainly NOT get rid of it for a scope, having also just looked up the price of those things at £1,100 on cpc before being discontinued its a no brainer , you will regret it when you then want to replace it.

author: echap
author_rank: Contributor
timestamp: November 11, 2015, 07:41:19 pm
content: OK guys, thanks for the insight. Rupunzell nailed it, I am overwhelmed. I work on antique and Ham radios, thus I consider myself a pretty good 1950-1960's radio tech, aka capacitor changer, but want to learn more. These new scopes sure do make it easy to see what's going on. I am reading and learning how to use this thing, so I will keep it. It was just an idea, as I don't see how I would use it at this point and by selling it, I could get a new toy. I sure would hate myself if I had to replace it at a later date after I get smarter.I am getting ready to restore a 1951 Zenith Porthole TV, and wanted to be able to look at the test waveforms. This was my motivation for buying this scope. The expensive probe was something that I was not planning on, thus thought about selling.Here's a pic of the TV, I know you guys are pretty high tech, but it's still pretty cool and I am looking forward to getting the old gal working again.

author: Cubdriver
author_rank: Unknown
timestamp: November 11, 2015, 07:56:04 pm
content: I'd be inclined to hold on to it if I were you. (This of course is me speaking as someone who just bought one after a fair bit of time watching eBay to get one at a reasonable price)Given what you paid for the scope and probes, you essentially got it for free. While it's tempting to think "This thing is potentially worth a couple of hundred bucks if I sell it", I'm more of an "it's better to have it and not need it than the other way around" kind of person and would look at it from the point of view of "I got an expensive probe for nothing - sweet. I might not have a use for it right now, but if I do in the future, it will cost me nothing to keep it.-Pat

author: tautech
author_rank: Super Contributor
timestamp: November 12, 2015, 02:09:45 am
content: Quote from: echap on November 11, 2015, 07:41:19 pm+1The P6021 is a sought after probe, hard to find cheap these days, keep it and value it.Treat it with great care and it will serve you well.

author: Rupunzell
author_rank: Frequent Contributor
timestamp: November 12, 2015, 04:24:43 pm
content: Autoset is not a replacement for operations skill, understanding and knowledge of how to use any item of instrumentation properly and to all of it's capabilities.With the advent of the modern DSO-MSO packed with automated features, computer data interfaces and such it can make acquiring data easier, except they are not a substitute for honest to goodness skill and proper understanding of the fundamental knowledge of electronics and all related.Better to take the time and effort required to learn to get the very most from your current Tek 475, then get what ever modern DSO if needed or desired. IMO, adding another time domain instrument to the mix now is likely going to cause more grief, confusion and slow the learning process.It's great to see restorations on vintage electronics such as this. It is preservation of technologies history and heritage for the future. One of the most negative aspects of technology is for the past to be completely discarded and replaced with any techno-widget under the guise that newer is always better without careful and in depth examination of the actual needs for technology.BerniceQuote from: echap on November 11, 2015, 07:41:19 pm

author: Ian.M
author_rank: Super Contributor
timestamp: November 12, 2015, 05:21:58 pm
content: There've been times I would have nearly killed for a calibrateable isolated current probe when servicing TVs, usually when the set was eating line output transistors. BU2525A transistors didn't come cheap, and it would have been good to know that the transistor wasn't spending too long outside the continuous rating line of its S.O.A. Of course that isn't so much of an issue with valves as the plate glowing red is a bit of a give-away, but O.T.O.H NOS replacement line output valves are not exactly cheap or common nowadays.

author: Deathwish
author_rank: Unknown
timestamp: November 12, 2015, 05:58:31 pm
content: I have to admit this is the only time I am jealous of Americans. They live in a place where there is so much quality kit for peanuts it makes me drool.

author: Cubdriver
author_rank: Unknown
timestamp: November 12, 2015, 06:49:33 pm
content: Quote from: Deathwish on November 12, 2015, 05:58:31 pmWe are certainly very fortunate (even spoiled) in that regard for sure!-Pat