Sony TC-366 runs slow after a period of time

[richieyork]

Hi all
Bought a Sony Tc-366 reel to reel. Its complete. Went through all the mechanics. Regreased, lubricated,cleaned, reprofiled rubber surfaces, everything. Sound is superb, crystal clear and all controls working correctly. Left it switched on (motor turning but that's it) for a couple of hours then hit play. It was running about 10% slow. Grrrr. Why should that be, given it was working fine before I left it? No buttons or switches turned in the meantime. Is it a motor or capacitor fault?
Cheers
Richard

[Ted Kendall]

Check the motor run capacitor, certainly. Is the motor lubrication correct?

[richieyork]

Hi
Thank you. A little update. I've located both oil holes in the motor an applied a few drops of oil. I've run the machine again and as before it starts to lose speed but i've given it longer than before and the motor run capacitor(s) can is very hot to the touch - it's also bulging slightly at the contacts end. That can't be right, surely Should they run cool just as they would if as a reservoir capacitor in a wireless?
Anyway, i've gone to fleabay and found replacements - there is a 0.5uF + 1.5uF in the can. The circuit diagram shows a switch (50/60hz selector) wired across the caps so i'm figuring either one or both are needed for 50hz but i'm unsure hence just ordered a pair of caps at those values.
Richard

[barrymagrec]

Motor caps shouldn`t run hot or bulge. I think this machine uses 1.5uF for 60Hz and 2uF (1.5 + 0.5) for 50 Hz.

[richieyork]

Thank you for the clarification - It seemed wrong to me to have a hot running capacitor! I'm hoping it's not damaged the motor windings - anyway i'll await the replacement caps and not use it anymore for now. And yes, having rechecked my not very clear schematic it does indeed seem that for 50hz its the 1.5 + 0.5 in parallel.

I'll report more once the parts have been fitted - keeping my fingers crossed as it really is a fine sounding machine!!!

[richieyork]

Originally Posted by barrymagrec

Motor caps shouldn`t run hot or bulge. I think this machine uses 1.5uF for 60Hz and 2uF (1.5 + 0.5) for 50 Hz.

Indeed I agree they shouldn't.

I sourced some individual bolt-on caps on ebay as I couldn't find a can type with 0.5/1.5 in the can. They took a while to arrive (China Post - oh why didnt I check before ordering?!?!) hey ho. But they got here. Rated 400VAC.

Bolted on and wired in today. Suddenly the machine has a new zest for spinning the reels. Hooray :<) I hadn't realised how much slower it was running even from cold before. All seems good.

So, another machine rescued from an uncertain fate. Ans it sounds really special too. Happy days.

Thanks to all for your help and guidance on here.

[philips KT3]

Hi Richard,just seen your sony tc366 problem.I presume you hadnt seen my posts of sept 2016 re sony tc366/7 hot motors.It would have solved the problem in seconds.Glad you sorted it.Gerard in Chester