"I soldered in two 600 volt diodes back to back across the probes
input connectors on my Dick Smith ESR meter. About 1 or 2 amps
rating would be OK. Connect one diode with the anode toward one
probe connector and the other diode with the anode toward the other
probe connector.
I haven't had any problems in the 3 years I have been using my meter.
The diodes do not seem to affect the meter reading.
Hope this helps. "

I saw this modification in the documentation that came with the unit.
Let's say I placed the meter with this mod across a filter cap on a
120W audio amplifer without prior discharging, what would happen?