Ryan, using the schematic you posted, look down on the left side and find the antenna jack (J401).
now following that line you can see the first place it goes is to the relay contacts that switch between Receive and Transmit.
so, first step is to jumper across the RX terminals to see if it's the relay contacts that are at fault. to do this, temporarily connect a length of wire from the center pin of the antenna jack to the end of C11 that connects to the relay socket. (leave the relay in place for this test, and have an antenna connected)
if your receive comes back, you know it's the relay itself that is at fault.
if it does not come back, your next place to look is C11 itself. it checks good?
then your next most likely culprits are TR4, L3, and TR5.
to check the transistors, remove them from the radio and test them using the diode function of your DMM.
for L3, check continuity across the windings.
im going to stop there, as after this the possibilities start expanding.
having said all that, there is a good chance that you just need a good receive alignment.
Yes, i understand that injecting a signal into the antenna jack isnt going to give you a signal to peak. you will need to inject signals along the receiver path to peak each can along the way. unless you know how to do this, it's time to send it to someone who does.
trying to walk someone through that process online is almost futile as you dont know whether or not the instructions were followed properly and you can end up in an endless loop of "nope that didn't work" and "ok try this".
best of luck.
LC