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1960's Watkins Copicat MK III
Year: 1960's
Brand: Watkins
Model: Copicat MK III
Class: Solidsate
Owner: Jesse Gray
   
So the MK III Copicats used 3 different schematics and layouts. This one is the third which up until now I hadn't seen, which isn't strange because we don't see a ton of British tape echos in the states. This layout/schematic is also the least documented and the one of the harder ones to repair.
2023-03-01: Case repair, full cleaning, upgraded the case with 1/4 jacks and an IEC power connector. Full recap. I located a bad BC107a transistor on the input path for the oscillator and replaced it, this gave audio in to the Oscillation circuit, but the frequency was way off (down in the 30's when it should be 49khz for this model). I was able to get the frequency back to 49khz playing with the caps in the oscillation circuit.
2023-05-18: Finally tracked down the intermittent issue, the 220k resistor the end caps of the resistor had cracked from age, so a times they would connect then break connection. Then I would touch it with a test lead and it would connect again. Lots of flaking traces repaired on the pcb, and swapped some transistors that were out of spec. Spent a lot of time tinkering with the oscillator circuit to get it to play nice, a common issue on the mk3s.
 
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