Battery Mod vintage Compass (- General)
Here is a clever little 12v battery pack I built for my Tesoro. It is such a simple and easy mod that it has most likely been built by others also, I don’t know. But It works well for me. Should work on the Compass detectors also. This mod will convert your old 3 module battery pack to a 2 module system and eliminate the weight of one complete battery pack on your older compass detectors. A similar 1.5v cell to 9v cell mod has been done for years on the old Teknetics detectors with no adverse effects.
Please note!!! Proceed at your own risk.
Be clear and confident in your electronic abilities before doing this mod as you will ruin your detector if you plug this in and also plug in the other two battery paks. I have included the a picture of a Power Switch from my RM6. The wiring will be the same or very similar on all Compass 3 module battery scheems found on the pre-80’s Compass detectors.
Battery Pak mod: Study my picture and note that we are saving/using the two AA batterys that are connected to the battery pak clips. On the opposite side of the pak you need to cut out/remove the plastic partition that seperates the other two AA batterys. This will allow us to insert the new 9volt battery in this location. Leave enough plastic to prevent the shiny battery connecting wire/spring to fall out. We want one of the springs to remain also to help hold the new 9v battery in place. Clip out the other spring leaving enough of it to solder the new 9v battery clip wire to. Look at the picture again so you know which spring to clip out. Think the idea through before starting. The objective is to create 12v by simply wiring/connecting 2 x 1.5v batterys in series with 1 x 9v battery.
Aquire a new 9V battery clip and wire set and solder the wires to what remains of the old spring and post. It is most importand to make sure the black wire is soldered to the remaining spring portion. The red wire can be treaded through the holder and soldered on the opposite side to the full remaining spring located there. You are finished with the Holder. Now to re-wire the detector.
Re-wiring the battery connections:
Again study my pictures. One old un-modified 6 volt battery pack will remain connected between the labeled pins 12v and 18v switch designators.
The other two battery wire sets will be removed. Now all you have to do to finish up is reconnect the black wire from one of the old 9v clip wires to any negative labeled trace on the board. Lastly connect the remaining red wire from the clip to the terminal labeled 12v on the back of the on/off switch.
Final words: Do not do this unless you are confident in your ability. Think the idea through before starting. The objective is to create 12v by simply wiring/connecting 2 x 1.5v batterys in series with 1 x 9v battery. Note that you may experience a slightly shorter battery life using this set-up compaired to 8 x 1.5v batterys. This is simply due to the fact that the 8 batterys store more current than the 9 volt cell. BUT it won’t hurt anything if done properly. Consider re-chargables?