Sony TC 777

.this .is a synchro motor, timed by line frequency, so it has to run at speed. The shaft diameter is identical to my other machine as is the pulley on the motor. I also swapped belts, but it still runs slow???? My other machine has a solid capstan shaft while this on has a sleeve. Could the large wheel on the capstan be too large? Not likely, but I may also change that whole assembly.
 

kevinkr

Administrator
Paid Member
The pinch roller does not determine the speed the tape travels, the diameter of the capstan determines that - are they the same diameter on both machines? Not sure what the capstan drive arrangement is on the TC777, but I am assuming flywheel, belt and pulley on motor. (Does it have two slots or just one) If not I would assume direct drive like ReVox used. You haven't provided any information on where you are located so I have no clue as to whether you have 50Hz or 60Hz power. A deck designed for 60Hz power running on 50Hz power will run about 17% slow. I'm not a musician so have no way of knowing what 4 frets means in terms of pitch error.
 
Sony 777

I'm in Wisconsin, all 60 hz. The capstan diameters match, 8.4 mm. Motor pulleys match too. Motor is a 5 wire, hysteresis syncronis type, start cap at 2 mfd. It starts and runs fine, just slow. Belt is fine, the only thing left that I can think of is the large wheel in back of the capstan, but why would they be different?
 
I'm in Wisconsin, all 60 hz. The capstan diameters match, 8.4 mm. Motor pulleys match too. Motor is a 5 wire, hysteresis syncronis type, start cap at 2 mfd. It starts and runs fine, just slow. Belt is fine, the only thing left that I can think of is the large wheel in back of the capstan, but why would they be different?
It must have been produced for the European market? Do you know its origin?