In article ,
wrote:

Hi guys, I have a hallifcrafters s76 and asking if any one has installed a
dd103 digital readout in one. I have it all restored. RED N9GHE

Red-

Does your dd103 have the counter circuit needed to convert the reading
of your local oscillator to operating frequency? If not, you will need
to design that circuitry.

I found a service manual at:
http://gmcotton.com/ham_radio/misc%2.../Hallicrafters
_S76%20HF%20Reciever_Service%20Manual.pdf

I think you would need to take a sample of the 6C4 oscillator (V3)
voltage, either at the plate or the grid. Using a small capacitor like
10 pf should not upset oscillation, but may require retuning. Also, it
is possible the sample may be too small!

73,
Fred
K4DII