Roland Re-150 Space Echo speed suddenly doubled!

[Toxophilite]

  I have a roland RE-150 space echo
I've used one of these for years and generally service them myself
The one I have now I've had for a couple years (I sold my original one..ggrrrr stupid..and poor!)
Anywho today the speed of the motor suddenly doubled, on all three settings
I use this all the time and have a biggish show coming up on the 6th
I wonder if anyone has any insight as to what to look for
I'll post a schematic I had to squish it a bit as the site won't let me post the whole service manual

[Toxophilite]

further testing shows the speed control is not working AT ALL and the unit is running on it's fastest speed!

[Toxophilite]

A bit of looking at the schematic and some consultation with my electrical engineer(ex-ham enthusiast) brother-in-law saw me replacing a few electrolytics in the relevant area and hey presto the speed control works again
I think my space echo is due to have ALL the electrolytics replaced.
What's moor he passing dow his old Tektronics scope as he's upgrading!