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Motor Cap - Waxy Substance?

B

braincube

New Member
Background: I own a Sony TC-355 Tapecorder; recently opened it up, cleaned and lubed everything, replaced belts, demagnetized - the works!

My concern is that there is a pale yellow waxy substance that seems to have dripped out from the motor cap. During playback, music seems slow..

What does this indicate?
 
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If goo has escaped the capacitor, it may have lost capacitance and thus the motor torque may be below normal. You've done all that to it, why didn't you replace the capacitor? A bit hard to find perhaps but after you do it you will see if the problem has vanished.
 
Yep, that's the classic Sony motor cap issue. I've seen that condition quite a few times, and I'd recommend that you stop using the unit until you replace the motor cap. It is over heating (hence the waxy substance and eventually the gross smell that will come from the machine) and causing the motor to run out of phase and hot. It's not good for the motor to run it that way, so replace the cap and then enjoy that machine the way it's supposed to be. You can probably pick one up from Mouser, MCM / Newark, Digikey or any one of a number of suppliers. Don't get a used one, though - it's a very common problem with Sony decks of that vintage and type, so you're more likely to get a bad one.
 
That capacitor is place to supress electric noise caused by the motor. On Direct current motor it is an easy replacement. I guess you should use on of the same capacitance and equal or higher voltage on a AC motor (which I think it is yours)
 
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rotovator said:
That capacitor is place to supress electric noise caused by the motor, you can replace it by another capacitor with similar capacitance and equal or higher voltage limit.
[strike]
I think you don't need to replace it by an exact match, just observe the maxium voltage and a similar or higher capacitance.[/strike]
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Actually it's there to offset the winding phases in the motor which smooths out the motor's rotation. It's used as a run capacitor, and when it goes bad it will cause the motor to run hot and slow down. Stick with the correct MFD (uF) value, but you can go a little higher on the voltage rating (never lower). Also, you probably won't find one that fits exactly like the old one, so you might have to wire-tie it into place. Be sure to insulate the terminals as that motor runs at line voltage and exposed terminals are a hazard.
 
audiojones said:
Actually it's there to offset the winding phases in the motor which smooths out the motor's rotation. It's used as a run capacitor, and when it goes bad it will cause the motor to run hot and slow down. Stick with the correct MFD (uF) value, but you can go a little higher on the voltage rating (never lower). Also, you probably won't find one that fits exactly like the old one, so you might have to wire-tie it into place. Be sure to insulate the terminals as that motor runs at line voltage and exposed terminals are a hazard.
Click to expand...

So I need some sort of surface mount capacitor, eh? This might prove difficult - I read your response and it felt like the entire thing was written in another language. A few questions: First, what equipment will I need to accomplish this repair? Second, how does one wire tie something in place? Finally, how does one insulate the terminals?

I'm also a little confused on how to know exactly which capacitor to order..

I hope you haven't decided I'm a lost cause, yet. Thanks for all your help so far!
 
braincube said:
So I need some sort of surface mount capacitor, eh? This might prove difficult - I read your response and it felt like the entire thing was written in another language. A few questions: First, what equipment will I need to accomplish this repair? Second, how does one wire tie something in place? Finally, how does one insulate the terminals?

I'm also a little confused on how to know exactly which capacitor to order..

I hope you haven't decided I'm a lost cause, yet. Thanks for all your help so far!
Click to expand...

Nah, it's not a big deal. The replacement cap might not be the exact same shape or size as the one that's in there is all.
By "wire-tie" I simply meant that the replacement cap might not fit into the bracket that is holding the capacitor that's in there now, so you might need to use a wire tie (or zip tie) to hold it in place.

If you look on the side of the motor cap you will see some ratings like 15 uF or MFD (both mean microfarads) and a voltage rating number - VAC means AC Voltage, which is what that cap should me marked as. Just make sure that the capacitor that you order is of the same MFD (or uF) rating and the same or slightly higher voltage rating.

If you use commonly available insulated spade connectors (crimp on connectors for the slide terminals on the cap) then the insulating is all taken care of. The existing connectors on the capacitor wires might be just fine, so you may not even have to deal with that.

There should be a rubber boot or plastic shield on the capacitor now, so if you can get that to fit on the new one you're done!

Hope that clears things up!
 
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audiojones said:
Actually it's there to offset the winding phases in the motor which smooths out the motor's rotation. It's used as a run capacitor, and when it goes bad it will cause the motor to run hot and slow down. Stick with the correct MFD (uF) value, but you can go a little higher on the voltage rating (never lower). Also, you probably won't find one that fits exactly like the old one, so you might have to wire-tie it into place. Be sure to insulate the terminals as that motor runs at line voltage and exposed terminals are a hazard.
Click to expand...


You're correct. Actually, you answered in the time I was correcting my mistake, which I promptly realized after posting!!
 
braincube said:
So I need some sort of surface mount capacitor, eh? This might prove difficult - I read your response and it felt like the entire thing was written in another language. A few questions: First, what equipment will I need to accomplish this repair? Second, how does one wire tie something in place? Finally, how does one insulate the terminals?

I'm also a little confused on how to know exactly which capacitor to order..

I hope you haven't decided I'm a lost cause, yet. Thanks for all your help so far!
Click to expand...

if you look inside your deck - it should look a bit like the tc-252 - the motor run capacitor is mounted under the motor :

It's a 1,5uF + 0,5uF probably 250volt ac


252motor_cap.jpg
 
jan_stevns said:
if you look inside your deck - it should look a bit like the tc-252 - the motor run capacitor is mounted under the motor :

It's a 1,5uF + 0,5uF probably 250volt ac
Click to expand...

Alright, I'm gonna go purchase one and swap it out. I'll let you guys know how it goes.. Should I remove the residual wax? What's the wax doing in there in the first place?

Wish me luck!
 
braincube said:
Alright, I'm gonna go purchase one and swap it out. I'll let you guys know how it goes.. Should I remove the residual wax? What's the wax doing in there in the first place?

Wish me luck!
Click to expand...

Do remove the "wax" - and to answer the last Q : it's the dielectricum that works the inside of the capacitor, thus creating higher capacity.

read more here, if interrested : http://en.wikipedia.org/wiki/Capacitor


(hmmm... when do you use "thus" or "hence" ???)
 
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(First, sorry for the lag .. it has really been awhile!)

I replaced the motor capacitor with another from a similar Sony model - instead of a new one, a used one. The capacitor blew again.

I'm going to buy another (a NEW one this time), but could the problem also be some electrical issue? Perhaps bad resistors or other components somewhere?

Anyone have a similar experience?
 
I would try a new cap and see what happens. Chances are the old used Sony one that you put in there had the same issue as the bad one that you took out. It's a very common problem with that Sony part, so it's pretty easy to believe that a used replacement would have the same problem. If there was a short or something like that causing it then I doubt that the motor would be running at all, and most the motor would be stalled and emit smoke or show other signs of shorting. Make sure that you are using the correct type of AC motor run capacitor with the proper ratings.
 
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