5V/Div is only stable setting

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Johnnz
Posts: 2
Joined: Sun Dec 11, 2016 3:23 am

5V/Div is only stable setting

Post by Johnnz »

Hi,

After assembling the unit V4 voltage was only at 0.9V. I checked R13,R14 and R15 and they were all fine.
I reflowed the solder on the analog switch and op amp leads and then I measured 1.4V at V4, hopefully this is high enough.

The issue I have now is that 5V/Div is the only setting that gives a stable trace.

I am using a signal generator 600 ohm output to provide a test signal.
If I use any setting other than 5V/Div the trace goes completely unstable with large spikes causing the trace to basically swamp the screen.

Any hints on what may be causing this?

Thanks in advance,
John
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: 5V/Div is only stable setting

Post by jye1 »

Can you post a photo showing the issue? We had similar report about large spikes displayed for some sensitivity settings and the phenomenal appeared power supply related. If you can please try a different power supply.
Johnnz
Posts: 2
Joined: Sun Dec 11, 2016 3:23 am

Re: 5V/Div is only stable setting

Post by Johnnz »

I tried the scope on another power supply and success! Seems the issue is something to do with my bench power supply.
Thanks for your assistance.
:D
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