This is from the service manual for the Radio Shack PRO-197 which is nearly identical. I don't think it is available online.
The words battery, backup and heap do not appear in the service manual. I don't see any type of backup battery tied to the ICs.
The troubleshooting flow charts don't really appear to indicate the precise problem you are experiencing.
Pin 10 of the 100-pin IC307 (CPU) is labeled as "Reset Input".
Pin 25 of IC307 is labeled as "LCD Reset Output"
Pin 46 of IC307 is labeled as "DSP Reset Output"
Transistor Q305 (a 2SC4116) is labeled as "Reset". 3.3 VDC feeds through a 10K resistor into the collector of this transistor. The collector of this transistor is also tied directly to pin 10 of the IC307 CPU labeled as "Reset Input". The emitter of the transistor ties to ground and the base of the transistor feeds off to numerous parts. It would appear that Q305 may briefly short pin 10 of IC307 to the ground to reset the CPU. I'm always leery of shorting any pin carrying voltage to the ground however as the voltage first passes through a 10K resistor prior to pin 10 this may be ok.
Pin 12 of IC311 (Flash Memory) is labeled as “Reset”. It appears there is 3.3 VDC typically present at this pin. This pin 12 ties directly to pin 120 of IC310 (DSP) (a 144-pin IC). I imagine a brief interruption of the voltage from pin 120 resets the flash memory. I'm not sure how a person would interrupt the voltage to pin 12 other than cutting the trace and fixing it afterward. I would probably not short pin 12 to the ground as it may damage the circuit.
Pin 24 of IC313 (CODEC) is labeled as “Reset” and ties directly into pin 58 of IC310.
So, there may be hope of resetting either the CPU or flash memory if you dare.
This looks quite challenging viewing the inside of my scanner. It appears IC307, IC310 & IC311 are on one of two boards in the display / keypad section and possibly under metal shields which may have epoxy over the solder holding the shields in place. Anyway, it's a last resort.