Racer - Impact - Battery-Power Completely OFF

[Funfinder]

When I start to improve stuff I often find additional issues, so here's the next mod:

Its not good when a device still consumes power even while its switched off,
especially not if accus are in use. Its possible to interrupt the battery-contacts
with little plastic-sticker but thats stupid work if there is a poti with on-off switch.

The mod is super simple:
There is a 5 pin cable from the poti to the PCB (from arm-rest with batteries part):

1. Remove the batteries and open the detector-housing, get the cable from the poti.
2. Cut off just the brown and the black cable*, close at the PCB's side plug.
3. Solder the black with the brown cable and insulate it.
4. Cut off one of the cables which comes from the battery housing (red or black).
5. Connect one end of this cable with the brown and the other end with the black cable.
6. Solder plus insulate it, plug the 5 pin cable correct back in and close the detector.

Now the Makro Racer or Nokta Impact really is OFF if switched to off and
no longer wastes any energy. Time for this modification: ca. 15 minutes.



* The color-codes are for the Makro Racer and also should match for the Nokta Impact.
Perhaps someone here who has the Impact can test and confirm that there's no difference.
If in doubt its very easy by multimeter to check out which cables belongs to the on-off switch.

[Skippy]

I'm wondering why Makro left the circuitry powered up, even when OFF, there's a reason, surely?. Does the machine remember it's settings with your modification? Maybe the switch contacts are a bit rubbish, and continuously turning on/off the power may eventually wear out the switch?

This modification reminded me a bit of a change I was once thinking of making to my Fisher F75. That has a proper ON/OFF volume control, which DOES switch off the power completely. However, the knob can be easily knocked when the machine is packed in a bag with all the other stuff like trowel, pinpointer, headphones etc, turning it ON. To solve this problem, what I always did was insert a strip of plastic under one of the battery terminals, in a way like you described.

I tried to think of a more convenient alternative. Two I thought about were:

*Adding a small switch inside the battery compartment, that was accessible by opening the battery cover.

* Adding a switch to the headphone socket, such that when the 1/4" plug is physically inserted, the battery power is switched ON. Then all you need to do is make sure your headphones are unplugged when you pack it away. I think it would be possible to make a special 'dummy plug' which when inserted in the headphone socket, turns on the power, but still leaves the loudspeaker operational, should you need to use the speaker, eg. broken headphones, or when air-testing at home.

I never actually tried these mods, I just use the plastic strip still. It works, I've got used to it.

[Funfinder]

This "power not really OFF" is the drawback of better assembling-disassembling options for the electronic components:

There is a little 2 pin plug which connects the plus and minus cables from the battery-compartment with the PCB.
Its some kind of "stick the different parts together" by plugs instead of soldering everything.
They would need at least a Poti with 1 single pin connector for one of the battery connections
plus additional a 4 pin connector that goes to the PCB. And of course for the second battery connection
another small 1 pin connector for the PCB. That way its possible to keep the easy assembling options.

Or they can leave it as it is but then 1 of the PCB copper-lines must go straight and directly
from the 2 pin battery plug (the plus pole line) to the 5 pin Poti on-off switch cable connector.
A poti with 2 connectors would be the more useful way than changing the whole PCB-layout!


The Makro Racer keeps its settings also with no batteries inside - per instance if vibration was set to on
and I guess the Nokta Impact, too. The ca. 0,5v which are to measure at the PCB when the power is "off"
(the original setup) wouldn't be enough to power the display-part-PCB anyway.

Yes, plastic-strips - ca. 0,3 mm thin and flexible to clamp between the battery contacts. Simple but effective!

I also have some plans for a special plug or socket to power the external vibration-circuits by the detector batteries.

And I soldered some kind of plastic-protection near the Blisstool on-off knob to prevent it from unaware "auto-power-on"
through rubbing inside a bag etc. This was especially necessary because the internal LiPo accus otherwise can deep-deplete.