Hello! In fact, I had a chance to measure the transformers in the interface today. The “AC power” interface measured 160 ohms on the primary and 6370 ohms on the secondary. The audio transformer measured 0.7 ohms on the primary 163 ohms on one secondary and was “open” on the other secondary(see attached image) Looks like your are correct! I have a message in to Roger in the hopes of getting a replacement transformer, or the specs so I can try to find one. In the meantime, if you (or anyone you know) might have an R1 interface or transformer I could buy, that would be GREAT! I know the R1 are old, but both panels are working well and they are most definitely worth saving!!!