Aerochrome
Active Member
I recently made a thread about capacitors in my wire recorder, before realizing that there was a tube/capacitor package that was not on any of the schematics. [Please note that there are four tubes in the upper left hand corner here, making a total of six]
It seems entirely home made, and is built upon a flimsy piece of metal, and screwed into the chassis in a way that screams home bodge.
Does anyone have any ideas what this might be? I can easily restore the wiring to the schematic, but before I do I want to get some opinions on it first as well as field guesses as to what it is. My best guess is a mod to make one of the pin pairs an audio out and the other an audio in, stock the audio jack swaps between an input and output based on what mode it is in.
One of the tubes is unmarked, but the other is a 6C4 tube. Before I give an annotated schematic, it is worth mentioning that the schematic is for the 78 model, not the 78-1 model that this unit is. However based on how bodged the extra "board" is I can not believe that this is was due to the slightly different version. The capacitors in the added board are also from a much more recent era than the caps in the rest of the unit.
From the added board: One wire [Brown] goes to pin 7 of the 6x4 rectifier, the black and red wires go to the pinout on the back of the unit (not the audio out, but to the pair of pins that would be shorted when the unit turns on normally), and the striped wire goes to the ground pin of the audio input on the front.
It seems entirely home made, and is built upon a flimsy piece of metal, and screwed into the chassis in a way that screams home bodge.
Does anyone have any ideas what this might be? I can easily restore the wiring to the schematic, but before I do I want to get some opinions on it first as well as field guesses as to what it is. My best guess is a mod to make one of the pin pairs an audio out and the other an audio in, stock the audio jack swaps between an input and output based on what mode it is in.
One of the tubes is unmarked, but the other is a 6C4 tube. Before I give an annotated schematic, it is worth mentioning that the schematic is for the 78 model, not the 78-1 model that this unit is. However based on how bodged the extra "board" is I can not believe that this is was due to the slightly different version. The capacitors in the added board are also from a much more recent era than the caps in the rest of the unit.
From the added board: One wire [Brown] goes to pin 7 of the 6x4 rectifier, the black and red wires go to the pinout on the back of the unit (not the audio out, but to the pair of pins that would be shorted when the unit turns on normally), and the striped wire goes to the ground pin of the audio input on the front.
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