Unit got zapped by 48 volt

Support
1

I worked with a device connected to a 48 volt DC power supply (400 mA). The voltage levels on the components are 3.3 V.

My brand new Logic Pro 16 accidentally got zapped by the 48 volt DC. I believe one of the uncovered tips (of the harness) of the ground channels on bank/group 1 touched the 48 volt rail and I saw a small spark.

I checked, the unit seems to be still functional. It’s detected fine by my computer, and it’s still able to capture. Based on the spec, it can tolerate up to 25V.

Even though I set the current of the power supply to be low (400 mA), but I am concerned that it may have damage inside.

So, what should I do at this point? Is there a way to do a thorough check to make sure all of the channels are ok? Should I buy a new one? Is it covered by warranty?

2

Glad to hear the unit seems to have survived! Yes, this type of accident is covered under the warranty.

If you have a signal generator handy, there are 2 tests we recommend:

  1. slow triangle wave test. This is basically the same test we use at the factory to test & calibrate units. Setup a slow ramp, 1 second duration, Across the full range of your Logic Pro 16 (or the full range of your signal generator, if it can’t reach Logic Pro 16’s range. (Note, Pro 16’s range is advertised as +/- 10 volts, but in reality, it’s about +/- 11 volts.)

Turn on all analog and digital channels.

Test the signal on every input port. 1 channel at a time is fine, I recommend just leaving the software running in looping mode while you move the input signal from pin to pin.

You should run this test 3 times, once for each threshold voltage.

Verify:

  1. the triangle signal looks correct.
  2. the channels next to the triangle signal have minimal, or no cross talk.
  3. make sure that the digital channel transitions at around half of the threshold voltage. (e.g. 1.65V in 3.3V+ mode)

This will verify most of the functionality of the device.

A second test you can run is to feed in a higher frequency signal (e.g. 100 MHz square wave, or the max square wave frequency you can generate w/ at least 1.2V amplitude) and record that on the digital channels at 500 MS/s.

If you observe any abnormalities, please post them here or send them in to support: contact.saleae.com.

If you don’t have a signal generator handy, you can repeat the test w/ a few fixed voltages, e.g. 0V, 3.3V, 5V, and make sure the analog & digital readings are correct, and that there is no shorts input to input.

3

Hi Mark, thank you so much for the clear instruction.

  1. For the slow triangle wave test, with +/- 10 volts, it looks fine, except some cross talks when I connect/disconnect the signal.
  2. For the higher freq, I can only get a decent square wave up to 5 MHz (verified with my scope). I saw constant cross talk on the analog when I set it to 50 MS/s. And when I set the digital to 500 MS/s, it changed the analog to 12.5 MS/s - I only saw “dots” on the analog, and the digital is ok.
4

Glad to hear it! Some cross talk is unavoidable, but you can usually reduce it my keeping the other wire harness wires physically away from the wires in use. if you notice any problems with the device, don’t hesitate to contact us.