I think the TC377 uses the same motor.
Check C707 on the motor. For 60HZ use 1.5uF 250V Metallised Paper and for 50HZ place a 0.5uF in parallel. Making 2uF.
Check C707 on the motor. For 60HZ use 1.5uF 250V Metallised Paper and for 50HZ place a 0.5uF in parallel. Making 2uF.
.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.
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?
They shouldn't be different. I'd start by getting one of those inexpensive laser tachometers on eBay and figuring out exactly how fast each motor runs.
Would run very fast were that the case. U.S models usually don't have multi-voltage capability.
I believe I have solved the problem. This is a 5 wire motor, and it is fed through 4 .1mfd capacitors. I replaced all 4 and now it is running at the correct speed. I will be verifying this tomorrow. Strange, huh?
Got it! Works properly now. BTW, if your reel holders are worn, try a tye-wrap. I'm still using mine after 60 years....
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