You are on the right track but I can't see where you setup T1CON. As the delay you need is 75,000 instructions and timer1 can only count to 65,536 then you need a prescaler. You appear to have chosen 8 when 2 would provide better accuracy. You can also use the assembler to do the calculation.
Code:
Period equ 0x10000-(.75000/2)
movlw 0x10 ;set timer 1 to prescaler 2
movwf T1CON ;but don't start it yet
movlw high(Period)
movwf TMR1H
movlw low(Period)
movwf TMR1L
bcf PIR1,TMR1IF ;clear interrupt flag
bsf T1CON,TMR1ON ;start timer 1
wait btfss PIR1,TMR1IF ;wait for interrupt flag
goto wait
Thanks very much Mike I greatly appreciate your help. It works now! I will visit this board more often I think.
Seems like I don't quite understand how the prescaler works, I thought using a prescaler of 8 would have made it more accurate and not the other way around