How does one set the top speed in early Lenz decoders?
Back around 2000, I hardwired two Lenz decoders in a Kato PA ABA set A units (the B unit is a Kato shell on a LL dummy chassis, with an early Soundtraxx sound decoder and a *ooooge* vertically mounted speaker).
I recently dug these up to run them, and while the motor control is excellent, their top speed is way too high. I've since got in the habit of limiting all my passenger power to 50 smph; that was the limit on the fast sections of Cajon trackage, and mostly run them much slower than that. Unfortunately, these decoders don't seem to support Vmax, and I don't have the documentation (or have it lord knows where)

I don't even know which version of Lenz decoder they are... But I have pictures!
So, anyone here have any idea how (or whether) it's possible to set top speed on these? Lenz info talks about "trim" but it's only in regards to acceleration/deceleration, not top speed.
Thoughts and suggestion appreciated. I'd like to keep these, as their motor control is excellent.
Thanks, Otto K.