Help with SCORPION 1 MPU rom error 1

[dickie12]

hi ive got a deluxe only fools and horses machine £3 jackpot i have put a post about it further down, it works but had no sound just a humming from the speaker that pulses with the lights, its got a scorpion 1 mpu anyway i removed the battery on the board and then the sound worked but still had humming noise in the back round i used it for around an hour no probs then switched it off. 2 days later i switched it back on and comes up with rom error 1 the machine still works but no sound again is there anyone here that can help cheers