Negative voltage on input

Color oscilloscope with touch panel
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Habi
Posts: 2
Joined: Sun Jul 02, 2017 6:47 pm

Negative voltage on input

Post by Habi »

Hello everyone.

Please, excuse my poor English. :roll:

I have a DSO112 that sometimes after power it on the input just showed a maximum negative signal, independent of scale. After some fiddling, it worked again as normal.

But now it’s doing permanently, always negative both on AC and DC coupling but about cero on GND. :(

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I’ve tried to download the schematics on http://www.jyetech.com/forum/viewtopic.php?f=17&t=358, but it seems the files have been corrupted. Anyway, I have opened the oscilloscope to diagnose it.

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And to my surprise, there is a negative voltage of about -3.6V on the solid state relay before the connector.

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In fact, if I select DC coupling I can measure the same on the crocodiles.

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Any ideas of what is happening? Is there an alternate download for the schematics?

Thanks in advance.
jye1
Posts: 1228
Joined: Wed Feb 20, 2013 4:58 pm

Re: Negative voltage on input

Post by jye1 »

We PM'ed you but didn't see reply.
Habi
Posts: 2
Joined: Sun Jul 02, 2017 6:47 pm

Re: Negative voltage on input

Post by Habi »

Sorry, didn't received notification on PM.

I'll do as instructed. :)

Thanks.
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