A friend has a Rigol DS1202Z-E, he wanted to take some RF voltage readings so used his scope to measure the voltage across his 50R dummy load (Bird 8251).
He had read multiple articles and Youtube videos on doing this and as far as he was aware the max voltage limit on his DS1202Z-E is 300V as per the input labels and documentation.
Using his Apache Labs Anan 7000dleMK2 SDR Transceiver with an Array Solutions Power Master VSWR/Power meter inline he transmitted 10W @ 3.65MHz in to the Bird 8251 dummy load and saw 22.4Vrms on the Rigol DS1202Z-E which is correct.
Happy with his readings and calculations he proceeded to transmit 100W (Expecting around 70.7Vrms) in to the dummy load at 3.65MHz and again measure the voltage across the dummy load with the DS1202Z-E, but something wasn't right it was giving a spurious reading. Thinking it might have been an incorrect setting on the scope and not wanting to reset it to defaults he moved over to CH2 and it gave the 22.4Vrms, so he proceeded to transmit 100W and now CH2 is giving spurious readings.
He then tried 10W again on both channels and still getting spurious readings, so he connected the scope probe back up and went to check the built in squarewave. That was not right, so he reset the scope to factory defaults and all readings are spurious, DC or AC.
Measuring across CH1 with a DMM it seems that has gone really high Z (infinite) and across CH2 it's in a few Mohm ranges. So something has blown in both front ends.
The DS1202Z-E was connected to the dummy load with 50R coax through a BNC T-Piece, as probes were not used this would be at 1X directly to each input.
He's spoken to the dealer (Telonic) where he bought the scope and they told him on the phone after they did some quick calculations that he hasn't done anything wrong and it should cope with that, they then said they will speak to Rigol and get back to him.
Rigol replied with
If there are no signals greater than 300VRMS the customer can’t damage the oscilloscope.
I guess that the generator generates spikes >300VRMS because both input channels are destroyed.
I recommend to use a high voltage probe to absorb any spikes that can occur.
And now the dealer is asking him if he would like a quotation from them to repair the scope, but first of all told him he hadn't done anything wrong and the scope would be fine with this.
He's frustrated as the dealers reply and also Rigol's reply indicate he's done nothing wrong and as far as he's concerned he's not exceded the Max voltage input and has no possible way of generating over 300V, but now has a broken scope!
After he called Telonic back in response to the email from Rigol forwared to him they have asked me for a wiring diagram, which he has provided, they are going to make further enquiries with Rigol after he stated he was not happy with their catch all 'it is broken, so he must have put more vrms in than he should have' reply.
To exceed the 300V limit quoted by Rigol that would need to be over 1800W in to a 50R load.
I know a lot of test equipment voltage input is derated depending on frequency but I cannot find any information at all on the DS1202Z-E regarding any frequency related derating, there is no mention of this anywhere in the product specifications or the user manual, nor can I find this information on any other Rigol scopes. Does anyone know what this is on this model or series of scope?