The manual for the TM-252a does not explain how to use the repeater functions.
REPEATER SELECTION

Put the reciever into VFO mode.

For Fixed (UHF recieve VHF Transmit) repeater, press Function REV and input
the UHF frequency for recieve.

Change back to VHF and input the transmit frequency.

Shut down and Power up with the REV button held in to access menu B.

Go to #69 and turn the Freq selection knob to select CROSS.

Hit any other function key and you are now in cross band repeater mode.
(one way only). 

To use a single band VHF repeater mode input a VHF frequency and access
menu #69. Select REPETR (the 1st choice), press any other function key 
and you are in single band repeater mode. The radio will record up to
16 seconds and then retransmit after the incoming transmission ends.

Note #70 will toggle between instant retransmission (OFF) and ON which will
give a 500ms delay before retransmission.

If you are in memory mode before you access the Menu B, #69 and #70 will
not come up as you cycle thru the menu and you cannot access the repeater function.

Have fun  
Dan McAuliffe  VE7SRT.