In article ,
Gareth Magennis wrote:
Hi,
I have here a tape echo, Evans super echo SE-810, with a non working capstan
motor.
Can't find any schematics for this, so am looking for generic info what this
motor and driver circuit might be, so I can diagnose and fix it.
Photos he
Motor with connectors
http://tinypic.com/r/28stz05/9
It's a four-phase motor.
Drive circuitry
http://tinypic.com/r/34e2txh/9
Looks like a four-phase oscillator.
1. Before doing anything else, replace all the electrolytic caps.
2. While you have the board out, make sure the windings in the motor test
okay for resistance and that those TO220 transistors aren't shorted.
2. Look at the Uher 4000 for a good example of this general phase shift
oscillator design.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."