Philips PM-2412 analog multimeter


Not in showroom condition but I have seen worse

This is a rather big meter, about the size of a Simpson 260. It is from the 70’s. It had the remainders of a leather etui. That was beyond repair. It is also missing the carry-strap on top.

As you can see on the picture below it has been used a lot. The traces for the monoknob, as Philips calls it, are pretty worn. But it still works, that is after some TLC and a new trimmer pot. It is now within specs but just on the edge.  Most analog meters are not very accurate and also not lineair. I have a Pantec that is bizar accurate. I can make it better by replacing resistors but there is no need for that.


The inside

This meter has 2 cool features. It has two fuses but not normal ones, there are 4 screw terminals and 2 bobins fuse wire. If the fuse goes open you unwind some wire from the bobins and then mount a new piece of wire. You can see it on the picture above (right-top) The other thing is an overload relais, with a reset button. This meter has a lightbulb to show the relay is tripped. It has 3 transistors for the protection circuit. The long “rail” around the circuit board is the current shunt. The fuse-like thing is a sparckgap to protect to high voltage.


The triplight

The downside is it needs 3 batteries. 2 are 9V and a 1,5V D cell.

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