Hi heyheyrr,
Ken is correct it is always better to know the model of jukebox you want help on.
With regards to Rowe Jukeboxes over the last 50 years there has been no way to reduce the speed on them if the jukebox is operated as it was made.
The turntables are run by motors using idler wheels or are belt driven on the R-84 to R-93
The turntables could run fast if you are using a 60Htz (from the USA) machine on 50Htz in the EU without a form of conversion. On the idlerwheel situation then the speed is altered by the use of a speed spring fitted on the motor shaft. On the beltdrive option then a different size pulley is used on the motor.
Please let us know what the model number is and in what country you live in.
Regards
Alan Hood
ami-man
UK