Scope probe failure - Page 1
Forum section: electronics / beginners

author: JonPyro
author_rank: Regular Contributor
timestamp: February 05, 2019, 06:41:46 pm
content: Hi all,Recently had a rigol probe fail on me. Attached is all that it outputs with any input signal.I have had it replaced but just wondered what might have failed in it, I thought most probes just contain a large resistor and a tuning capacitor.Any thoughts?

author: ArthurDent
author_rank: Super Contributor
timestamp: February 05, 2019, 07:11:04 pm
content: Looks like A.C. coupling and the square wave rises to its peak value then as the capacitor charges up, you see the exponential decay as the voltage out drops to zero. Then you get the same in the negative direction and it repeats. Check that the resistance from tip to BNC isn't open. Here is a typical schematic of a 10x probe. Probes should not read infinity.http://electronics-diy.com/schematics/967/Scope-Schematic-1.jpg

author: ataradov
author_rank: Super Contributor
timestamp: February 05, 2019, 07:15:29 pm
content: Probably a small fracture in the wire or a series resistor that turned the probe into AC coupled one. Check continuity from the tip to the BNC connector.

author: JonPyro
author_rank: Regular Contributor
timestamp: February 05, 2019, 08:58:25 pm
content: Sadly due to the time pressure of my warranty running out (in one day) I have already sent it back to confirm my free replacement so I can not measure the continuity......i am sure you are both correct

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 06, 2019, 02:41:19 pm
content: The orinal probes of my Rigol DS1052E were also pretty crappy to the extend of being almost unusable.They have a switch to switch between 1:1 and 1:10 and that swich does not work properly.I should have send them back to Batronix years ago, but instead I just grabbed my other probes wich are of a better quality.Another common failure are the rotary encoder knobs of these scopes, and mine also suffers from that. Some people have gotten free replacement frontpanel boards, but mine is out of warranty for years now and I've also made some modifications myself.(For example the USB connector on the front panel was upside down, wich was quite annoying, but I fixed that).

author: Gary350z
author_rank: Regular Contributor
timestamp: February 07, 2019, 09:31:28 am
content: Quote from: Doctorandus_P on February 06, 2019, 02:41:19 pmThe switch on the probes on my Rigol DS1052E were also bad. I had them replaced under warranty, but the replacements were also bad. 4 out of 4 probes were bad. All the switches were intermittent. Not very good probes in my opinion.Does anyone know where to get some good probes for a Rigol DS1052E scope that would be a match for this scopes quality/price? (What I mean is buying expensive probes for a low end scope doesn't make good sense)

author: ataradov
author_rank: Super Contributor
timestamp: February 07, 2019, 03:36:14 pm
content: Quote from: Gary350z on February 07, 2019, 09:31:28 amI Just epoxy the switch in 1:10 position on all my probes that I use often. I do have a couple probes that have switch as is, but I never had to use them. Makes the switch very reliable.

author: ebastler
author_rank: Super Contributor
timestamp: February 09, 2019, 10:59:38 pm
content: Quote from: ataradov on February 07, 2019, 03:36:14 pmWith the DS1000Z probes, I found that the slide switch just moves far too easily. I kept switching from 10:1 to 1x accidentally. Fortunately, it is easy to pry out the yellow slider, leaving a small recessed switch lever. No more unintended switching, and if I absolutely want to, I can still switch to 1x with the help of a small screwdriver or paper clip.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 10, 2019, 12:34:55 am
content: Those small probe switches can sometimes be a source of amusement too () once they either seize up or get wonky.They either need some working back and forth, but usually a nano dose of contact lube 'somehow encouraged' inside without fallout spillage is how the drama concludes,with the switch performing/clicking like new and or better.I have some old school 15 mhz Trio-Kenwood probes that have to be sort of pulled apart, and put back in their indicated 1x or 10x spot.Idiot proof as it gets, my first choice for lower bandwidth testing,and always left in the 10x position for 'next time'------------------FWIW the Siglent 200mhz and Atten 100 mhz 1x-10x cheapie probes supplied with the DSOs have been reliable so farand very close in performance. But hey, I baby all my probe leads, and loan to no oneTBH if I'm in 10x territory, I always block off the switches with a scrap of something, and put non gunky electrical tape over themThis way they stay on 10x during a higher voltage or suspect test set up,and saves my credit card any further grief