Dial Master Telephone
Remco produced a number of different telephones and walkie-talkies in the 1950's and 1960's. My sister acquired a pair of yellow phones from eBay and asked me to see if I could get them operational. As of this posting, I have the ringers working, but no voice transmission. Next time I see my sister, I will give the mouthpieces a bit of a shake-up to free the carbon particles that are critical for speech transmission.
Update: I got about 1/2 an hour today to work on the phones again. I tapped around the rim of the mouth pieces with a tiny mallet and reconnected the phones. I could hear clicking in the earpiece when the phone was dialed. By a trial and error process, my sister and I discovered that by rotating the dials through about 4 digits and holding them there we could communicate quite clearly. Next time I work on the phones I will need to open them up again in an attempt to discover why they have a "sweet spot" for communicating and see if it can be adjusted to be independent of rotating the dials.
Patents: US2764631, US2764748, US2819351
Update: I got about 1/2 an hour today to work on the phones again. I tapped around the rim of the mouth pieces with a tiny mallet and reconnected the phones. I could hear clicking in the earpiece when the phone was dialed. By a trial and error process, my sister and I discovered that by rotating the dials through about 4 digits and holding them there we could communicate quite clearly. Next time I work on the phones I will need to open them up again in an attempt to discover why they have a "sweet spot" for communicating and see if it can be adjusted to be independent of rotating the dials.
Patents: US2764631, US2764748, US2819351