I want to modify the internal beep sound pressure level of this bench DMM and make it louder.
I have a problem with my ears and I won't be able to hear the the beep sound well when making continuity measurements. The beeper is small (well, not so small, is a Murata piezo speaker.) Looking at the schematic, the Murata is continuously receiving 5VDC, and when you use the continuity mode shorting the probes, the circuit sends around 2.4VDC, with a mixed square wave to make the beeper/speaker beep noise.
I was thinking of using a kind of simple design using an opamp (the 34401A has a 12VDC rail inside,) or maybe with a couple of transistors will be better.
Maybe I'm getting deaf, but the only DMM I can hear is the Fluke 87, which uses a differend kind of beeping sound, bi-frequency, not a "piiiiiii" one (which, if you vary your head's position with respect to the DMM you won't be able to hear it well)
PD: Here is the part of the schematic which shows the piezo speaker: