Many of my projects have a cutout for a Jensen 123-A, API 2503, Profile 4804, etc. size output transformer with applicable cutout, mounting holes, and respective pads for wire leads. In some instances, one might want to use a commonly available PC mount transformer by Jensen or Cinemag.

This adaptor board allows you to use a Jensen 123-S-PC, Jensen 123-DBX, or Cinemag CMOQ-3 PC mount output transformer in place of the 123-A / 2503 footprint on my projects. Alternatively, you could use this as a wire-lead breakout board for the respective PC mount xformers.

Although I don't have photos / build guide, I would recommend soldering single pin headers to the bottom of the PCB for all respective wirepads and then using an applicable height insulated standoff/spacer for the mounting holes (to be sandwiched between this adaptor and the project PCB) for a solid mechanical connection.

The two mounting holes are the 123-A / 2503 spacing. The holes are 3.81mm / 0.15" to fit a #6 bolt. Pin header plastic body height is around 2.6mm, so a 3mm height spacer should be okay. Gave a couple options in the BOM but obviously you could source your own options elsewhere.

The Jensen 123-S-PC style transformers share the same footprint but have a different secondary pinout than the Cinemag CMOQ-3 or Jensen JT-123-DBX (which have the same pinout as each other), thus jumper pads are included to use one or the other.

• Jump Pin 1 to Pin 2 (center) on the pads to use a Jensen 123-S-PC, or...
• Jump Pin 3 to Pin 2 (center) for CMOQ-3/JT-123-DBX.

...and as explicitly stated: this is an open-source project for D.I.Y. purposes only, not for resale and not for profit.