Velleman LAB-1 Mod

Here is a simple mod for 3 in 1 Soldering Station, Regulated DC Power Supply and Digital Multimeter – Velleman LAB-1.

Multimeter module is operated using 9V battery that we don’t want to use. But how to replace it?

Well, we can use Regulated Power Supply module instead of a battery, but that could disrupt operating of this module and can cause voltage drops when we use it for powering some other circuits.

But there is another possibility, we can use power from Multimeter LCD backlight socket, unfortunately it’s 9V AC. So we just need to convert AC to DC, no problem!

We will need four regular diodes to create Gretz bridge, one 10V Zener diode, 1k resistor and some 16V condensator to regulate to 9V DC, according to the schematic below.

As you can see I’m saving 9V battery terminal and attach my power module with another socket. This way we can return to original state and use battery again.

I have covered back side of the PCB with some hot glue to make permanent isolation.

This PCB fit’s perfectly in to the 9V battery holder!

Connect everything and test the power module. There are no permanent joins, everything is plugged in on female pin headers!

We can also add some switch to turn whole module off when not used.

Drill a hole on the back of the cover and attach the switch.

Now you can turn off multimeter when not needed or use it without replacing battery!

Checkout my other Velleman LAB-1 mod!

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