[Heathkit] info needed - Heathkit frequency standard

[Michael Tortorella]

Looking at a Heathkit model 10A-4510-1 circuit board also marked 85-1521-1.
Looks like a frequency standard, has TTL with 1 mHz, 100, 10, and 1 kHz
outputs.  Does anyone have a schematic or hookup info for this?

Thanks and 73

Mike W2IY