Sjouke Burry wrote:



Maybe a silly suggestion, but check your scope 1khz signal.
Because those are not very reliable signal sources, specially
in old scopes. The square wave is usually oke, but the frequency
might be off. Maybe your voltmeter has a frequency measurement range.


** That might be the case OR the capstan roller has gone smooth and hard with age and is failing to control the speed of the tape through the capstan gate.

With this sort of defect, tape speed can increase or decrease, depending
whether the take up reel or supply reel has more torque. A simple test is to see if it is easy to pull tape through the capstan gate with the machine turned off - if it is, you have a problem.

Having serviced many Roland tape echo machines made back in the 1980s (the famous Space Echo and Chorus Echo models ) I can say the one fault common to practically ALL examples seen is a shiny, smooth pinch roller.

Since no new supply of suitable rollers exists, I fit the old one with a suitable shaft and lock it into the chuck of a bench drill spinning at 600rpm - then, using finger pressure on a piece of fine sand paper wrapped around strip of wood, gently remove the shiny surface & restore the needed matt one.


.... Phil