Problems with functioning HPS10

When using the HPS10 with measuring AC voltage, the HPS10 gives a very low reading. When using a diode, the HPS10 cuts off the AC-signal at the top of the curve instead of positive or negative. The auto-setup function seems to be not working. Perhaps the measuring probe is broken. How can I test the measuring probe?

Can you please elaborate on this problem. At this time, we have no clue what the problem might be. What are you trying to measure ? What do you see. WHhat are the settings ? Does it measure DC ? Try with a battery…

We are using the HPS10 in school (vmbo, vehicle mechanics, pupils at age of 14…16, ) for a lesson in which they have to rectifie an AC-voltage of 28 volt. The big advantage of the HPS10 with AUTO-setting is, that the pupils don’t have to adjust the scope. It is done automatically. At least till 2 weeks ago. I don’t know what happend. Since then the HPS10 is functioning strange. The AUTO-setting does not work anymore. And instead of 28 volt, the HPS10 measures 4,1 mV. When using one diode, the ac-signal should change to dc: the positive (or negative) part of the ac-signal should dissapear. Here the HPS10 acts very strange: The new signal starts with positive sinus-curve. The signal is cut of the top of the positive curve, falls to zero, continues with the negative sinus-curve, is cut off at the negative top of the sinus-curve, falls to zero and continues again with the start of the positive sinus-curve.

I don’t understand it.


Did you try a different probe ? Does it measure DC correct ?
If this is not the case, the input circuit probably got damaged, e.g. due to an overvoltage. Return the unit for inspection, as it is not user servicable.

There is a test signal point inside the battery holder at the back of the scope. This would give you a basic check that the probe and the input circuitry were working.

Hi,I am in New Zealand and am curious where to send my HPS10 for repairs as I fear I may have fed high voltage into it whilst in 1x on probe.

You can find the address in your HPS10 manual.

Velleman Instruments Repair Dept.
Legen Heirweg 33
9890 Gavere