so i've had a little civil defense geiger counter for aaaaages, but it stopped working years ago, and i started poking around in it to try and fix it. i replaced the batteries, which were intensely corroded and had hecked a bit with the surrounding material too, and cleaned the inside a bit. the original "calibrated in 198X" slip and everything were still fresh inside, neatly. sadly, the batteries didn't fix it? so for a while my brain was stumped, and i didn't know what to do about it. i left it till i had better ideas.
well, i've always liked crystal radios, the styling and function of pre-IC electric work. for those who know me, it's very much in the wheelhouse of my turn of the century interests. i've never had the components to make one, till recently! i bought a whole slew of germanium diodes for just a few dollars, as i'm saving all the money i can, and the only component i was missing was a speaker--that was, one i was sure i could use. i have several i've collected from electronics over the years, but only a few high-impedance microphones, and i was never sure if they'd be high enough. a microphone, you see, is just a speaker with the information going the other direction, and can be interchanged.
but, this geiger counter has a high impedance headset, in mono, for listening to the clicks it gives. i've always thought it might be useful in this regard, but never knew what the stats were for it, and couldn't be sure how to use it either. tonight, my curiosity hit again. i went and grabbed it, to see if there was a way i could disassemble the headset and make it more useful for a radio, without the strange plug from the counter. and then, curiosity struck twice. with the counter not turning on, i turned to an online pdf of the manual for it, which not only gave me the visuals i needed to know i had not fixed it wrong before, but that the headset is perfect for a radio.
this bothered me, though. if i didn't put the batteries in wrong, why WASN'T the counter working? so, i took out a multimeter and started checking the batteries, and then connections. the batteries were all fine, full, never used. they just... weren't getting power anywhere else. i checked continuities, and a simple goof actually got me on the right path. i tried both probes on the same battery contact, and they didn't connect, which was strange. they should have! in fact, none of the battery contacts were conductive enough for continuity, on the surface. after a little more poking, i thought, alright, i just gotta DO IT. put on a glove, took the batteries out. sure enough, it was an oxide layer, and where the batteries should have contact was oxide and corrosion. i cleaned these off, put everything back in, and VOILA, IT WORKS AGAIN, and it's even got proper clicks from the test source and everything! that said, after rotting on a shelf for [at least] 40-ish years it's not in great accuracy anymore.
so uh, does anyone know how to calibrate a CD V700 6B?
