Originally Posted by hap
I connected the cap and resistors from BB3 to 4 other TMS1100s - two were B-revision dies and two were E-revision. Interestingly, the Es are faster than the Bs- B amateur = 169K, B pro = 218K, E amateur = 188K, E pro = 244K. The original chip was a B, so I guess 169K/218K is the way to go.
Thanks! It's probably times-2? eg. (169K*2)hz: approx 340khz.
I didn't think about that last night, but those numbers are pretty slow. I used an oscilloscope on pin 18 and measured about 6uS between peaks for amateur and about 4.5uS for pro. To get more accuracy, I measured the time for multiple peaks and divided. I averaged the timing for the two B chips, but they were pretty close.

The frequency vs resistance chart in the TMS1000 manual doesn't have a plot at 33pF, but extrapolating, 47k ohms could easily be 340kHz (just noticed that's at 15V and I measured at 9V, not sure how that affects it). That would put Pro at 436kHz, which is a little over the maximum recommended oscillator frequency of 400kHz. The manual does indicate a +/- 20% frequency variation, though.

I'll measure some other TMS1100s in their original circuits and see how they compare.