I could use some help with a non-urgent problem with one of my Spectra 22... Someone (me) snagged the 15VAC bias supply cord and apparently broke/detached the female 3.5mm socket internal to the MK-2123 interface box. Before I dismantle the speaker and dig into the MK-2123 it would helpful to know what sort of socket is used! Does anyone know how that socket is attached to the PCB?
The bias supply is fine and the speaker plays fine as-is, which is why I describe the situation as non-urgent. If someone were to unplug the bias supply, however, it could become a major problem when trying to plug it back in!
The bias supply is fine and the speaker plays fine as-is, which is why I describe the situation as non-urgent. If someone were to unplug the bias supply, however, it could become a major problem when trying to plug it back in!
The jack for the 15-VAC input is soldered to the printed circuit board which contains the ultrasonic bias power supply. Not sure how much difficulty you may have finding a replacement with the same footprint. However, it would not be terribly difficult to replace the jack with a panel mount version mounted on the rear of the interface chassis. Then run wires from the new jack to the old solder pads on the board. Not polarity-sensitive. Just be sure to clean up any metal shavings after you drill the hole. I spec'd in that pc-mount jack, but that was also 30-some years ago. The brand SMC rings a bell, but that could be a faulty memory.
Thanks AAM. It should be interesting to find out how/why a PCB jack is so loose--yet still seems to function. Maybe the traces lifted along with the jack... I plan to order several different styles of 3.5mm jacks (both PCB and panel-mount) to increase the odds of having a suitable replacement available while the Spectra are "down".