Roland JD990 intermittent freezing

Hi I have a Roland JD990 rack module that intermittently freezes up. Powering off and back on again resarts it.
This happens every 30 mins to a couple of hours.
Someone suggested bad electrolytics in power supply may be likely suspect - it is about 30 years old after all.
Does this sound plausible? Has anyone else encountered this problem in 90s Roland digital synths? Any suggestions?

Thanks very much.