Video Teardown & Repair of the Siglent SHS810 100MHz 1GS/s Portable Oscilloscope - Page 1
Forum section: electronics / testgear

author: Hugoneus
author_rank: Frequent Contributor
timestamp: July 07, 2015, 03:16:39 pm
content: In this episode Shahriar examines the failure of a Siglent SHS810 100MHz 1GS/s portable oscilloscope and multimeter. The instrument’s multimeter inputs are functional, however the neither of the oscilloscope inputs display the correct waveform. The displayed signal varied largely as soon as a coax cable is connected and the instrument is powered from an external signal source. This hints to a grounding problem. Further examination of the probes also shows large damage to the ground pads from a possible high-voltage short circuits through the shared ground between the scope inputs.The disassembly of the unit reveals heavy damage to the ground PCB traces of the input channels. After thorough cleanup of the PCB, the ground traces are repaired using copper tape. The new ground plane corrects the problem and the scope can now be used to measure RF signals correctly.Watch the video here: [27 Minutes]youtu.be/71UtSij1KQkMore videos at The Signal Path:http://www.TheSignalPath.com

author: Muxr
author_rank: Super Contributor
timestamp: July 07, 2015, 03:52:52 pm
content: Enjoyed that. Nice repair!

author: free_electron
author_rank: Super Contributor
timestamp: July 07, 2015, 04:07:40 pm
content: hahhaaa. looks like someone connected the probe earth clips to a live mains ...boom. byebye ground trace

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2015, 06:07:34 pm
content: I think 3 phase mains! That is way more damage than you'd get from shorting a single phase 220V 16A circuit. I'm still wondering why the grounds of the 2 channels are connected together. I'd expect fully floating channels on this kind of equipment.

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 07, 2015, 06:42:32 pm
content: Quote from: free_electron on July 07, 2015, 04:07:40 pmThat doesn't explain why the grounded metal on the top of the probe is so damaged. If it was just the earth clip it would not show any damage above the ground clip connection.Quote from: nctnico on July 07, 2015, 06:07:34 pmLooks like you are not alone in expecting that

author: SeanB
author_rank: Super Contributor
timestamp: July 07, 2015, 06:47:23 pm
content: I would guess they wanted to measure the high side switch of a large SMPS and at the same time the low side switching waveform to the bottom driver. Would work with a meter with isolated inputs which they had used before, but this new one is not isolated, so the bang and dead probes. They probably had used a Fluke scopemeter previously, which has isolated channels, but did not check on the Siglent that it is not isolated for each channel. Went bang when going to connect the top ground lead to the output, with the most damage occurring when the top driver promptly went dead short and the main capacitors discharged through the meter cabling.

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2015, 06:51:38 pm
content: I think someone stuck the probes into a 3 phase outlet trying to measure the voltage. It's not the ground lead clips which got damaged but the metal (grounded) part near the the tip. Usually that is not connected to anything.

author: HighVoltage
author_rank: Super Contributor
timestamp: July 07, 2015, 07:24:28 pm
content: Quote from: nctnico on July 07, 2015, 06:07:34 pmMy old Tektronix THS720P has two floating channels.Great video!What a treat, two repair videos in one day.Thanks

author: Muxr
author_rank: Super Contributor
timestamp: July 07, 2015, 08:42:31 pm
content: You know, come to think of it. It's kind of mean to copy features, down to the layout and then decide not to implement floating inputs. That's just asking for this type of failure

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2015, 08:50:03 pm
content: Quote from: Muxr on July 07, 2015, 08:42:31 pmIt's user error and nothing else.Isolated channel models:http://www.siglent.com/ENs/pdxx.aspx?id=93&T=2&tid=2Quote

author: Hugoneus
author_rank: Frequent Contributor
timestamp: July 07, 2015, 09:08:41 pm
content: I think it is okay to not have isolated inputs as long as this is clear to the user. As others have mentioned, there are isolated versions available.

author: Muxr
author_rank: Super Contributor
timestamp: July 07, 2015, 09:38:29 pm
content: Quote from: tautech on July 07, 2015, 08:50:03 pmI was commenting on Siglent's blatant copy of the design from Fluke's Scope Meters. I can easily see a mechanic used to Fluke's scope meters grabbing this thing and expect it to behave the same, and than proceed to fry it like the above example. Scope Meters are popular in the auto industry.It's obviously a user error, was I disputing that?

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2015, 10:04:43 pm
content: Quote from: Muxr on July 07, 2015, 09:38:29 pmShow us a link showing this, I wasn't aware of your quoted "blatant copy".If it issurely there would be copyright issues, anybody aware there is?

author: Muxr
author_rank: Super Contributor
timestamp: July 07, 2015, 10:06:46 pm
content: Quote from: tautech on July 07, 2015, 10:04:43 pmhttps://youtu.be/71UtSij1KQk?t=106

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2015, 10:52:10 pm
content: Quote from: Muxr on July 07, 2015, 10:06:46 pmI don't believe copy of the front panel UI is anything to get excited about.Across the massive range of test equipment there will be many examples of front panel layout that will be identical, so what? Proven layouts are popular, cause less confusion and make interchangeability of brands less painfull for users.Dave made comment of the similarity of the front panel layout of the recently released SDM3055 bench meter to a similar Agilent unit....the do look similar on the outside, but internals are VERY different.One must also be aware that instrument case manufacturers supply to many different instrument manufacturers and examples of very similar looking units are everywhere, especially from Asia.What, so we'll next start accusing HH DMM manufacturers of copying each others layout?I don't think so.

author: Muxr
author_rank: Super Contributor
timestamp: July 07, 2015, 11:09:47 pm
content: Quote from: tautech on July 07, 2015, 10:52:10 pmTake it easy dude, I was taking a piss at Siglent, which you obviously take way too seriously.

author: CosPhi
author_rank: Regular Contributor
timestamp: July 08, 2015, 05:42:53 am
content: Quote from: Muxr on July 07, 2015, 08:42:31 pmFirst: Siglent does make two version of this scope. The fully isolated SHS1000 series (orange) and the blue SHS800 series with the common ground on the two channels. The price for an isolated SHS1000 model is more than the double from a unisolated SHS800 model.Second: The two channels from Flukes 120 series scopes are also NOT isolated from each other. Flukes 43B power analyzer has also two NOT isolated channels from each other.Third: I guess ALL these days handscopes looks "a bit" in the same way. Just like "all modern" smartphones look the same and a car has four wheels. But it's clearly not just a copy of a Fluke handscope.To use a handscope doesn't just mean to work on high voltage and you have to use an isolated scope. To have common grounds even is in a lot of situations better. And yes, of course, it's much cheaper and more easy to build a scope with a common ground.Sadly there is no video of this ...... fun to watch andVery thank you Shahriar for your videos anyway. Very impressed each time again

author: retiredcaps
author_rank: Super Contributor
timestamp: July 08, 2015, 06:17:16 am
content: Quote from: CosPhi on July 08, 2015, 05:42:53 am+1. I love the repair process videos.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: July 08, 2015, 03:13:52 pm
content: You are welcome! Glad you liked it.

author: Unknown
author_rank: Unknown
timestamp: July 09, 2015, 03:13:45 pm
content: Martin Lorton has a really good video showing both the isolated-input model and the non isolated-input model and how the difference will affect certain measurements.Steve