"The phone is a remarkably complex, simple device, and very rarely ever needs repairs, once you fix them." - Dan/Panther
Started by oyang, November 07, 2015, 06:58:22 PM
Quote from: oyang on November 08, 2015, 05:46:22 PMThe coil has 4 connections to the same terminals as the one in the WE subset, and is marked 99-A.I've recently gotten 3 Kellogg subsets at about $15 each.... So I figured they are common and available. Are they actually rarer than the 634A?
Quote from: oyang on November 08, 2015, 10:37:09 PMThanks for the review.Maybe this is why the box doesn't ring for an incoming call? The striker does vibrate, but not hit the bells. I thought this was just a matter of adjustment to be made, but could it be because the coil isn't right?Showing my inexperience, let me ask: does the induction coil play any role in sound transmission? I thought it was purely a converter of DC to AC, to allow the bells to ring because the AC current then alternates creating magnetic impulses on each side of the striker. Speaking of which, can one buy an appropriate induction coil from a modern source like Radio Shack? With the setup I showed, the 151AL dialed out and received calls fine, with both transmission and reception of sound that seemed good.Thanks,Otto
Quote from: oyang on November 09, 2015, 11:56:41 PMThanks for these last 2 detailed posts!
QuoteYou are correct about the two different ringers. The "slide 3" is the final tested rewired subset; "slide 2" is a different subset that was identically laid out and so I used that picture for convenience. I had not noticed that the ringer types were different, because everything else was the same. I was planning on rewiring the "slide 2" subset the same way, so sounds like it should work as intended.The sound quality was quite good, so I haven't tried switching the terminals of the induction coil.
QuoteQuestion: Once I have added the second capacitor and there are now a 1µF and 2µF wired the same as the 634A subset, doesn't this now become an anti-sidetone configuration that can utilize the black wire from the desk stand? Or is the problem that the induction coil doesn't work for anti-sidetone?
QuoteYou guys were right that this is addictive.... It's very zen to sit quietly studying a wiring diagram, stripping wires, crimping, testing my connections with an ohm meter, ending up with a physical object that functions. This contrasts with my job sitting in an office, staring at a computer screen, writing papers or grant applications, getting interrupted constantly by my students and lab staff to figure out why their experiments failed, going to meetings that accomplish almost nothing: the academic rat race!
QuoteI think the take-home message from this thread so far is "a little knowledge is a dangerous thing." I've learned just enough about telephones to mess around and think I've accomplished things I haven't (i.e. making a 634A-equivalent subset).