OWON 100MHz SDS7102V Repair

[Zero999]

One the channel 1 input is damaged. A colleague of mine connected one of the probes to a current transformer and injected a high voltage into it. The probe was melted and charged but was easily replaced.

Now there's a permanent 280mV offset, when the probe is connected to a low impedance source and DC coupled, which doesn't go away after running the auto-calibrate routine. It seems like the offset is caused by 280nA leakage current. When the input isn't connected to anything, the offset disappears. When I connect my multimeter to the input, it measures 280mV on the voltage setting and 280nA on the current setting.

Has anyone else had a similar problem?

The input is screened with a metal cage, which will be difficult to unsolder so I haven't done anything, except remove the case.

[tautech]

Shame, any lessons learn't? (don't lend your scope)

Don't know if rf-loop can help you, he's an Owon dealer.

[Zero999]

Shame, any lessons learn't? (don't lend your scope)

Don't know if rf-loop can help you, he's an Owon dealer.

The silly sod didn't apply Ohm's law properly. The burden resistor he used didn't have a high enough power rating, smoked, failing open circuit, allowing the poor probe and oscilloscope to take the hit.

PCB area .

Thanks. I'm not going to do much with it at the moment because the company is going to organise replacement/repair.

If get a new one, I can then take a closer look at it.

[Zero999]

I've messaged the ebay seller who sold it to me about this. He said he might be able to get it repaired, if I send him the serial number and a photograph, along with a description of the problem.

[Shock]

I've messaged the ebay seller who sold it to me about this. He said he might be able to get it repaired, if I send him the serial number and a photograph, along with a description of the problem.

Be careful with this as there is nothing to stop him from saying thanks very much and selling it off.

[Zero999]

That's a good point but even if they can't fix it, I'll still want it back as it's still of some use.

I think I'll get a new one ordered on the company, as it'll be the easiest solution.

[Shock]

That's a good point but even if they can't fix it, I'll still want it back as it's still of some use. I think I'll get a new one ordered on the company, as it'll be the easiest solution.

I've been caught in a similar situation over a smaller amount before, was a huge supposedly reputable seller as well (UK based I think).

What happens is communication stops dead as soon as they have your item or even worse they say it's ready after a couple of weeks and to send some money. As a rule doing anything outside of Ebays or Paypals protection generally ends in tears.

A better solution is contact a legitimate distributor or the manufacturer and go through them directly.

[Zero999]

Unfortunately I've messaged the seller, who doesn't seem to be very knowledgable. Here's a copy of our correspondence:

Dear Seller,

I have bought an OWON 100MHz SDS7102V and have had a problem with it.

A colleague of mine connected one of the probes to a current transformer, injected a high voltage into the channel 1 and damaging it. Now channel 1 has a permanent 300mV offset, when DC coupled and it doesn't go away after running the auto-calibrate routine.

Do you do repairs or know of anyone who does?

Thanks,

Dear Me,

Thank you, I think OWON prepare paid repair service, please send us the serial # on the back of your machine, and picture or video to show your problem, we will send to OWON for quote for you, thank you

Unfortunately it's not possible to provide a picture or video at the moment. The serial number is SDS7102XXXXXXX
To produce the fault follow the following procedure:

Switch on, the oscilloscope.
Use a x1 probe on channel 1 and set the oscilloscope input to x1.
Set channel 1 to DC coupled and centre the trace on the screen.
Short circuit channel 1 to 0V and the trace will move by about -300mV.

The leakage current causing the offset is actually present on channel 1. If a multimeter, set to read voltage, is connected to channel 1, it will read about -300mV. When the multimeter is set to read current, it will read about -300nA.

It seems as though the software is nulling out the offset, created by this leakage when it's turned on but it appears when the probe is shorted to 0V or connected to a low impedance source.

I hope you can help

Thank you, if you can send video or picture, I will ask if OWON can slove your problem by firmware then you don't need to ship back, if hardware broken maybe you can change board by yourself, and you don't need to ship back and force, so the video and picture will be helpful, or you want to ship back directly, let us know, thank you

I know it's not possible to fix the fault by firmware because it's a hardware fault. Channel 1 was damaged by connecting it to a high voltage. It needs a new input board. If you could sell me one, so I can fit it myself, please let me know.

I felt like banging my head on the computer keyboard, after sending this!