The EPIC 1 is the first generation of the SCM.
These are good SCM's if you don't have a SIMM, as they can take the 29F040 flash chips with a dip switch change. If you have one with a SIMM on it, remove the SIMM and install the chips! Use the SIMM for an EPIC 2 or 3.
The complete schematics are PNG format and are also available as a pdf
This is known to have a problem with no or low transmit modulation. This has been traced back to U306 in the audio processing stages on the SCM. It's a MAX292EWE+ available from Digi-Key for about 7 dollars.
You can tell these based on the real LEDs on the front, vs the light pipe with SMD LEDs on the others.
Note the light pipes on the LEDs