TSP #54 - Teardown & Repair of the Siglent SHS810 100MHz 1GS/s Portable Oscilloscope & Multimeter

hi welcome to the signal path I have another repair video for you guys and this time it is a sick land there we go portable oscilloscope this is a sigma and SH s 810 which is a 100 mega to channel 1 Giga sound per second or so the scope plus of course the multimeter function and it looks almost brand new he still has the LCD cover on it but it was listed as not working and as damaged and he has all of his accessories the probes the power supply and everything comes with it on the manual and the warranty course was essentially a new new unit but something has happened to it and it's been damaged and in this particular one actually my girlfriend wants to fix it but she's too shy to appear on camera so she's gonna work with me and we're gonna fix in the back row so the credit goes also to her if we can fix it and if he can't fix it then she's the one to play push you let us take a closer look at this unit I like this that the weight size ratio of the setting this is a nice portable unit that can be easy to use around the field there's a nice handle on everything and of course all the multimeter components are in the front it's rated to DC 1000 volts it's kateri rated ok and it's gotta the communists it's a little bit the coloring screen is really unusual because the common here is uh it's red and then this one is black it doesn't make any sense these colors not to me at least but it has a 10 amp input here for measuring contents unfused on the 10 amp that's pretty risky and then there's a six hundred milli amp when we choose fuse and of course the configuration here is soft button keys f1 through f5 which interact with whatever menu that appears on the screen you know directional pads and menu buttons and scope meter and recorder and you may seem familiar and that's because it is familiar and this is my fluke 190 C which is a 200 mega two-and-a-half-year sample per second he has a very very similar layout so clearly this is a layout that's been working and people have been comfortable using so Sigmund has in a way emulated that because it works well you can see that the order of the button is the same direction pad and soft key button is it the reasonably logical kind of layout it the voltages being adjusted on each channel separately the timescale here and moving the cursor back and forth so it kind of makes sense but anyhow this is a we're gonna focus on this another than 190c but I'm going to plug it in turn it on see what it looks like when it's turned on all right I think the battery has enough charge actually let's go ahead turn it on and see what happens there this siglent handheld digital oscilloscope sh a 10 with the website still going come on what are you doing seems like da there we go there this looks ok put it up into the oscilloscope I can see the two traces on top of each other red and blue and if I press meter they go is that multimeter function so I don't always like to know what's wrong with it so we're gonna have to play around and see what's going on now there's them the menu I guess I can enable and disable them anyway saw so it's a pretty straightforward I think the easiest thing to verify is to take a look and see if the multimeter works and because generally the multimeter circuitry is completely separate except for the portion where the OS is interacting with it then what is inside and look look the colors here this is red black red red and this here is red red black cracks it doesn't match I don't know why maybe someone has taken apart and these color things this come off and make us wish them well when I take it apart I'll find out if it can be switched or not but anyhow first let's go ahead and try out and see if the multimeter works it should be easy just to plug it into something I'll try it out all right let's measure some voltages I like the fact that when you select different functions it will automatically tell you where you have to plug it in that's pretty useful especially in stick colors don't match for example if I go from DC volts to let's say DC current you can see that it will switch it around to the two outer ones if I want a 10 amp range and if I go on the milli amp range then he goes on to the cross one so that's very very helpful especially if you have never used one of these before so let's put it back onto the amp strange and let's go back actually I want to measure DC voltage there is so this is my power supply over here and I'm gonna set the power supply to let's say 10 volts alright stay 5 volts here we go this is that yeah there I go power supply I'm gonna enable the output what do we see here we go 5 volts five point zero one one well it seems like a little bit off - I know that that I know that the power supply is pretty accurate maybe it's a little bit out of Cal but it's ok you know five point nine is fairly close I'm not unhappy with that we can also try and measure the current I can just go ahead and shorter than the 10 amp range simply because it doesn't matter it can take up to 10 M and the power supply is set to 1 amp let me go under DC current there and it's not telling me to connect it across here we go it should be 1 amp and it's zero point nine eight nine and the red regul power supply says one point zero zero one so I think it's a little bit out of cow but I I cannot find anything specifically wrong with the the functionality it seems like it's fine let me disconnect it from the power supply let's go back to the main unit and let's go to resistance let me go get on and I go on yeah I'm gonna short the outputs together there you go it's art arranging there you go pointing to ohms that's what correct so I think it's fine and the multimeter so whatever the problem is this must be I played around a little bit more with it as well I think it must be on the oscilloscope part so let's go ahead and before I D oscilloscope I go back to this scope it looks okay so let's take a look at the probes so these are the supplied probes with that come with this unit and they have times one times ten selection switches which is nice general quality I'd say it's pretty good nice soft cables that it's pretty good I think and but you know I was looking around and I was just going to about to use them and I took these off and let me show you what I found look at this you see what has happened I think this is a clue and what has gone on already wrong with this poor instrument you see that that is a lesson in oscilloscope common grounds between the channels so what I suspect this happen is that as you know the ground connection in an oscilloscope is shared between the channels you don't have an isolated ground so for example if you want to measure voltage 1 and you put voltage 1 here and you put voltage 2 over here the grounds are connected so you cannot put two different potentials on the ground lines if you do they are shorted and going to sink current through the probes and through the instrument and back out of the other probe then you're going to get a short-circuit as you can see here so I suspect that whoever has done this either accidentally or wasn't aware of this fact and has tried to put a large voltage with a lot of current carrying capability at these probes and I've shorted them out and subsequently basically melted the probes but if the probes are damaged it's surely the scope itself must be damaged because this is quite a bit of current to melt at the ground shield on these probes so anyhow I'm not going to use these probes therefore for for measurement anyway because if I go if I do then I don't know if the cable is damaged so we're gonna get rid of these at least as a variable in analyzing this and I'm gonna go ahead and try and connect there at the inputs over here which are up here channel 1 and channel 2 I'm gonna directly connect them with a BNC cable to let's say my function generator and it will be kind of nice to use this siglent SDG 5 1 6 2 to generate some arbitrary waveforms and put them into here see if they display anything i'm go to the channel stem or the nice thing is that both channel 1 and channel 2 are 0 so they're not stuck on high and stuck on low that would be a classic sign of the damaged digitizer at the very input of the unit so that's not is the fact that there are right in the center is is a good sign and hopefully that means that the problem is not too severe but that I think that kind of leads us to a path first it's connected with the BNC and see what it looks like so let me show you something I've gone ahead and actually plug the unit to the wall so we can notice from the external power supply and look all I'm going to do the I have a BNC cable the two ends are free I'm going to leave one end on the table and I'm going to go ahead and connect the other end directly to channel 2 look at this row there's nothing on this side and if I go ahead and disconnect this unit from the AC supply this signal gets significantly smaller this is a classic grounding problem because if there is no reference proper reference ground as soon as I connect this the oscilloscope to the wall then you have a reference with respect to the 60 Hertz S&V that's all around me and the ground is picking up a whole bunch of signal and normally the BNC would be a fairly good insulator so I shouldn't see that if I just have a BNC that has its and floating I shouldn't have such a bad signal if I have such a bad signal then the grounding of the oscilloscope is heavily compromised and that is that makes sense in conjunction with what we saw with the probes because the probes have the ground melted which means that a huge amount of current must have flown through from one channel to the other most likely destroying the grounding that's inside the instrument and that is consistent with this particular measurement that we see here if I go ahead and disconnect this guy you can see it becomes significantly better normally if you have an oscilloscope when you connect the probe to it if you touch the tip of the probe with your finger then you will see this and that's because you have your entire body picking up a signal but if there is a BNC with nothing connected to the end of it you shouldn't see that because it should be fairly shielded so that is a classic problem that we can see with something like this so let's go ahead take it apart I mean we're gonna take that out anyway now we can take a look inside here's the first part of our disassembly the battery of disconnected from the connector here and this is a seven point four volt five thousand milliamp hour battery lithium polymer and oh yeah it's interesting it's got only two two points of contact so it should be internally balanced somehow when it's being charged otherwise you couldn't do this but anyhow pretty nice let's move forward and here we go I took the top cover off I guess that should come out there it is yeah it's got metal inserts for the screws which is nice and it has to have that because the diffuse is on the inside of the unit says the only way to access the fuse here here are the terminals for the with a multimeter they're the 10 amp input doesn't have a fuse and the fuse on the 600 million people is unfortunately glass and no this a closer look at it there we go you can see the terminals from there and I should be able to change the color and flip this around someone surely must have taken to take this apart and I've done this I'd be surprised if that's the original but here you go you can see very very thick solder assisted thicker joint here for the for the ground terminal over there and here's a 10 amp and whatever the connection is the 10 amp is is underneath on the other side I cannot see it from here and we can see some protection circuit she wants to open it hopefully there's some relays and so on over here some my transformer here I'm not sure for what perhaps for the backlight display I don't think the backlight is LED I think it's a stealer kind of fluorescent tube type but anyway we'll take a take it apart further and find out so this obviously acts as perhaps both the heatsink for whatever is underneath here because I can see some thermal poxy although this doesn't seem to be making very good contact with it but I see some thermal putty in other parks eternal party underneath it so let's go ahead and take a couple more screws in and let's look oh there it is nevermind look at that you see that that is damaged on the PCB from the ground terminal so I'm afraid to take this off it's going to look pretty bad and this one doesn't seem to have any immediately visible damage but clearly this is this has seen better days and that makes sense with us what we saw from the probe the currents going through here and coming back yard anyhow I hope this is repairable because if the PCB is completely destroyed we'll have to do some reconstructive surgery alright taking that part off and here is the thermal party that I was talking about this seems to be in contact with the main processor here this appears to be a DSP processor from analog devices here's some memory is an ultra altera cyclone fpga and cypress most likely memory there's a lattice part there that must be a CPL d of some kind and this is the part for the multimeter it looks like it's almost an entirely independent module that's just plugged in top of everything this is really battery connects keyboard screen some more relays over here this is the the cable that is responsible for passing the high voltage to the tube that is the backlight like I said as I said this is a definitely not LED backlit so in every overall looks it looks pretty straightforward and I like the design it's a fairly an look they have gone ahead and and scratched off the parts on these components over here I suppose just to protect some IP or some design rights on these I'm not sure if that's really effective or not but anyway that's a one way to do it and are we going to go ahead and and take these apart as well there we go whoa look at that you probably can't see on camera yet but there is some serious damage over there these are of course the shields for the analog inputs they've done their their job well and then you see there we go there it is Wow take a look here there is a bit of explosion happening over here there's also I don't see much damage on this pin but if I wiggle it look you see he's not connected to the PCB anymore and that's what I suspected there is no grounding at all from the BNC connectors whatsoever so that's surely going to cause some problems so we have to see how bad this damage is and how it can be really can't be reconstructed and whether that's the only problem it has suffered I suspect it doesn't have any other issues simply because whatever happened from the high voltage or the high current circuitry that closed the loop here has gone through the ground and and then it looks like the connection from the BNC to the motherboard is as was has suffered the most so it should be fairly easy to fix be interesting to take it apart one step further and take a look and see what's on the other side of the PCB and how bad the damage is and then do some cleaning and move forward there we go I went ahead and I took the module that's responsible for the multimeter section out and you can see that there is a there's some protection plastic over here I wonder if they've taken care enough to you know so have the cat tree rating I'm not going to go into too much detail but indeed there is a wh 250 component here which is a resettable fuse on the 10 amp line so the 10 amp line is connected here before to the reset of a few before he goes out and so before it goes into the circuit and his monitors and so on through this through this component but which means that if you put more than 10 amp at least this will give you partial protection and this explains this uh-huh there we go that should do it I think I forgot now which way it was which way what's going on there this yeah now the colors are correct so it looks like someone has taken this apart at least I don't think that was from factory but there's another thing is that inside of this you can see here there's a whole bunch of residue I wonder if that's because of this smoke that's now been deposited on the inside of the unit after the explosion has happened but now you can see a whole bunch of it here see I can wipe it off like that that seems like it's deposited from that because since this component this part of this circuit is working there's some valuable resistors here which I wonder maybe it could be used to calibrate it further because it seemed that gets a little bit off cap but anyhow with an explosion inside of it who knows what has happened but anyway we don't need this component so for now I'm gonna take this out anyway because they're just gonna fall out them away now we just have to uh take it one step further I'm very curious to see what's on the other side of the board and see how bad the extent of the damage is and this side you can see the USB port there's a device and a host port which you can use to upload firmware into it and connect to that computer and there's a whole bunch of software that runs on the computer I come any case with it so it's nice nice instrument so let's go one step more alright after taking a couple of more screws off this unit comes up I hope you're sitting down and this is what we're dealing with this is a disaster we can see that the hood from the explosion is covering most of the surface mount components which appears to be all resistors all over here and all over here this damage is quite extensive and the smoke is reached all the way up to here the explosion pattern can clearly be seen from the leftover marks here and you can see where the the body was protecting whether it could be note the position this was where the back filters were there so the yeah eeehm filters at the back of the board so these guys were sitting on top and you can see that they have managed to maintain and to keep the most of the explosion in place and there was even some welding of PCB traces directly at the edge if this thing would focus directly at the edge of the cover so this was a pretty pretty nasty nasty mistake and has certainly destroyed most of the back of the PCB now the extent of the damage is not really known until we completely clean it so I suggest we go ahead and take these pieces of this this whole piece off completely by done soldering or just removing since it's already burnt up from the PCB now we'll clean up this open up this whole area for us to be able to clean it up and go ahead and use some acetone some alcohol to get rid of this take a closer look at the PCB under the light and see if it's repairable all right here we go removed the BNC connector so now all you're left is the board itself I'm gonna go scrub this and clean it up a little bit more brush it off actually I'm gonna let my girlfriend do this part of it she loves brushing PCBs how she just punched me there we go so let's go ahead and think of this sudden and I have to be clean it became Estes the damage better so this is as much cleaning as well as possible all this burn marks are now embedded into the solder mask and could not be taken off any more the resistors are a little bit more clean over here but this is all basically soot that's damage that's left off but if you look carefully you can clearly see the path insert interestingly enough there's one two three holes which are all ground this is the hole that used to be connected to the BNC and it's just vaporized and that's what's deposited everywhere this was the other one that was committed to the ground also vaporized you can see this whole trace over here is gone there's some exposed copper here there's some exposed copper here so I'm gonna do some reconstructive reconstructive surgery here I'm gonna rebuilt this trace with aluminum uh with uh with copper foil and I'm going to put it on and solder it all up together so it's going to look nice just like he used to be before I'm gonna do the same thing there and that's my cat in the background thank you very much but your help is appreciated and then now and now we can continue to do this and I build this over here and build this over here connect it all up and see if you can get it it will come back to life I looked at that a little bit under the light too and really this is the only piece the portion of the ground here you can see some better marked here this is all ground so if we reconstruct this and reconnect everything and sort of the ground back sorry the signal back and we can test it to see if he comes back to life if there is no other damage it's unlikely but it is of this ward to try because without the ground reconstruction we have nothing and then we can test that if it works up to 100 megahertz and see what happens there's a whole bunch of other components here and you can see of course relays the other protection circuitry here this relates to range to switch the range of the input when on the vertical range there's some variable capacitors here here and here and those rebel capacitor of course for tuning and dampening and getting the frequency response correctly I would be interested to know what the difference between this model and the 200 megahertz version is that would be an interesting thing to take a look at perhaps later but uh first thing I reconstructive surgery let me do this here with the help of my girlfriend and see what we can find out maybe it looks nice and now I'll show you alright here's the result of the reconstructive surgery you can clearly see that we cut a piece of copper tape and we have exposed the copper as much stuff goes left underneath it so that it's soldered on both sides and you can see that it continues to the ground and this side continues up to the ground this side this whole area is now ground providing us with a good RF ground like before same on this side you can see is all covered up and it continues the ground forward this is the RF input this is the RF input now interestingly like I said there was a symmetric ground point here so what I'm gonna do is I'm gonna flip the connectors around by a hundred degrees and use these as grounds even though we fixed this now we're gonna have a nice solid Graham but we don't have the point should puncture through this anymore we're just gonna use this hole and this hole which are all connected together anyway as our connection and then connect it up and see if it comes back to life and here's the finished part here you can see that we have soldered the center pad center pin of the RF connected back to the board and the ground is now flipped to the other side this is the damaged pin that doesn't have any anymore pad on it this is the other damaged pin that has no pad on it and you can see that by flipping the connector we can utilize the other ground connector and of course on the other side we have our extended ground connection all around enabling the ground to be nice and solid there's no not yet known if any of these components are damaged but you know you see the only way to find that is to power it on so I have to do assemble it a little bit more before we can go ahead and do that all right one step closer now it's back in the case and we're gonna continue assembling it and hopefully you don't work all right all back together I'm turning it back on and I'll actually plugged it in as well I close it up everything back to the way it was and I still booting there we go then go back to the oscilloscope screen now it's plugged in let's go ahead and plug some being seasoned to it see if I can get this PC out of here back into channel 1 here we go see that's much more promising you don't have those crazy crazy waveforms anymore with a floating ground there's two channels channel two so far so good and now we can go ahead and connect to our arbitrary waveform generator up here now I have set it over to be away from general to one megahertz on both outputs at two volt peak-to-peak into high impedance and I've also put them at ninety degree offset so I plug this one in here like that one here and oh damn it it is not the smartest way there you go we can still see it maybe let's go ahead and enable the outputs output one take a look isn't that beautiful look at that perfect they can change the time base let's see the change I hope you can see this I don't know how well it shows on camera there is there you go better look at it you can see no problem I can also change the vertical scaling which is really important because there are relays that will switch in a mouse for different levels of attenuation so for example I can go up you can see that he has no problem I can go down and then there was a relay that just clicked you can see that the other really clicked on the other side too so I can go ahead and change the output level to one volt peak-to-peak on one channel there it is you can see that it has no problem capturing that I can go ahead and do the same thing you see no problem you can make it even smaller there you go now it's 15 milli volt peak-to-peak I can make it even let's make it 250 what big Dookie no problem at all you can see it has no issue picking up much smaller signals looks good so what I really like about this repair is that first of all this was a good demonstration of what can happen if you in fact make a mistake and and don't take into account the fact that the ground of the oscilloscope is connected now this could have also led to an injury if somebody had touched the ground on the other probe and while the other ground was connected to high voltage so that's a good lesson to learn and the other thing I like about this is that you need I need that no equipment to repair this I didn't need any fancy components or anything I just used a piece of copper tape some soldering skills and that was it and you can bring it back to life just like that so it's a it's a really nice basically introductory beginner type of repair and it was a nice quick video you got to see what's inside DSHS a10 I like it it's a nice unit you know for I think it cost about five hundred and forty dollars for this particular model and they have a several different models maybe we can open it up and take a look at another one I'm trying to keep this video short so I'm gonna thank my girlfriend come on say something that's it yes there you go see that's the only thing she wanted to say she wanted to make sure that you guys don't think that my cat was my girlfriend thank you very much there it is though so I hope you liked it if you liked the video give it a thumbs up and leave a comment let me know what you think and oh yeah that's about it until next time

Channel: The Signal Path

Views: 27,870

Rating: 4.9873013 out of 5

Keywords: Portable Oscilloscope, Siglent, SHS800, SHS810, 1GS/s, Common Ground, Isolated Ground, Oscilloscope Safety, Repair, Teardown, Probe, Handheld, PCB Reconstruction, Fluke 289, Waveform, Multimeter, Calibration

Id: 71UtSij1KQk

Length: 27min 4sec (1624 seconds)

Published: Wed Jul 01 2015