Broken probe, how do I argue this with warranty. - Page 1
Forum section: electronics / testgear

author: nsled
author_rank: Contributor
timestamp: July 05, 2024, 06:10:29 am
content: I made a video of the problem hereAnd this was the response:"I have sent your video & questions to the engineer.Below the answerHVP series is not able to test the switching power. It’s the passive probe, only can measure power that is insulated/grounded. (your transformer is not grounded) You need a Differential Probe for your application. You can buy our DP-50Khttps://www.pintek.com.tw/productDetail/land-ctop-2/index/pscsn/17072/psn/241470Thank you.".Am I being gaslighted here? why would this 1000x passive probe read any different from the 10x passive probe. I don't know how to argue and demonstrate the point.

author: jonpaul
author_rank: Super Contributor
timestamp: July 05, 2024, 06:20:18 am
content: Response seems correct.See 1980s Tektronix Circuit Concepts books,"Oscilloscope Probe Circuits"https://w140.com/tekwiki/images/6/62/062-1146-00.pdf"probe Measurements"https://w140.com/tekwiki/images/1/19/062-1120-00.pdfjPS: poor test setup, hazardous HV at high freq.check HV forums for precautions

author: nsled
author_rank: Contributor
timestamp: July 05, 2024, 08:28:54 am
content: I kind of get where the argument is coming from, however I still believe its faulty. Why would 2 passive probes give completely different results? Show me a good test setup. As shown its a battery -> buck converter -> 240v inverter -> 6kV transformer.Narrowing it down to just the 240Vrms (338Vpeak) since it's a known voltage, the 10x passive probe on the scope measures it perfectly fine with the exact same connection whereas the 1000x probe does not.

author: tautech
author_rank: Super Contributor
timestamp: July 05, 2024, 11:05:40 am
content: Swap probe to another channel, reassign 1000x attenuation.Set channel to 1V/div.Sanity check with probe compensation output. 3V p-p 1kHz ?

author: nsled
author_rank: Contributor
timestamp: July 05, 2024, 01:16:29 pm
content: Quote from: tautech on July 05, 2024, 11:05:40 amThe other channels are the same. The 1000x probe does not register anything at the 3V output, the 10x checks fine.I just remembered that I put it on a plasma globe when I first got it (and took a photo), which measured 5kV. Now its measuring 10kV so it's definitely developed a fault somehow.

author: jonpaul
author_rank: Super Contributor
timestamp: July 05, 2024, 05:58:59 pm
content: scope term set to 50 Ohm or to 1 Meg?Most HV scope probes assume a 1M scope inout Zoj

author: nsled
author_rank: Contributor
timestamp: July 08, 2024, 12:58:07 pm
content: They seem really adamant that "As told, the HVP series can’t measure Floating Output.".I'm questioning my sanity here, is there any reason a passive probe like this cannot measure a floating output, considering the device being measured is isolated/battery powered? The 10x does it just fine. Isn't the floating voltage only a problem when the device and scope share a common ground?

author: TomKatt
author_rank: Frequent Contributor
timestamp: July 08, 2024, 02:49:58 pm
content: If the probe is damaged, it should cause inaccurate readings on non-floating measurements as well.I may have missed it here, but does it read correctly at all ?

author: jonpaul
author_rank: Super Contributor
timestamp: July 09, 2024, 05:33:58 am
content: test both probes on scope CAL test point, normlly a 1 kHz sq wave 1.0V or 200 mV.See scope spec on probe testj

author: nsled
author_rank: Contributor
timestamp: July 09, 2024, 08:41:03 am
content: It measures DC somewhat correctly, it's a bit out at 50Hz and about double the expected at anything over 500Hz. It's hard when I don't have a HV source with known voltage/freq. It won't read anything at the low voltage test point on the scope. I'm just checking its correlation with the 10x.They've agreed to have me ship it back.

author: H.O
author_rank: Frequent Contributor
timestamp: July 09, 2024, 09:27:10 am
content: A decade or so ago I bought a HV differential probe from them (Pintek). When I tested it I found it to show exactly double compared to a FLUKE multimeter. They said they've never seen anytning like it but promptly shipped me a new one. It arrived and did exactly the same thing...Only THEN did I realise what a stupid, embarassing mistake I've done having put the diff probe across positive/negative output of my tracking DC supply while the FLUKE was measuring between positive and ground.I shipped the replacement back at my expense. Emailed them, explained what had happened and offered to cover their cost for shipping and what not. They kindly declined my offer but thanked me for "confessing" and shipping the replacement back.Needless to say I found them very good to deal with.