Yes, you will need an inverter board AND make sure to get power to it.
OR
To convert the Sanyo monitor to accept normal, positive video:
1. Remove the wire jumpers that have been installed in place of
transistors TR201, TR202, TR203.
2. Remove R213, R214, R215.
3. Install the following components:
a. R201, R202, R203 100K
b. R210, R211, R212 100K
c. R213, R214, R215 820 ohm
d. R217, R218, R219 560 ohm
e. TR201, TR202, TR203 2SC1815 or equiv.
f. C202 220uf 16V
g. D210 1N4004