Ok, never mind. Fixed ours. Turns out you can use the meter core from something like an old Signet knotmeter, such as the MK 9, as it uses the same Hoyt meter core as the 250 deg Swoffer. The circuitry of the Swoffer is better though. Compared to the single scale Signet, ours is the dual scale.
Nice guy Bob Swoffer installed new electrical components, and also calibrated the rebuilt knotmeter. Turns out he has all the parts, including cases and labels, except for the Hoyt meter cores, which are far too expensive now.
He's now into building industrial flowmeters instead of sailing meters.