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02-10-2025 20:34:03  #1


Smith Corona 5Te Transformer Temperature

I have a 5Te in fantastic condition. I noticed the plate on the bottom near the motor gets very hot. So hot I can't touch it for more than a second. Is this normal? It seems like a heat sync but makes me wary of using it.

 

03-10-2025 03:29:14  #2


Re: Smith Corona 5Te Transformer Temperature

We will see what other members say, who may have more experience with these machines than I do.  But I cannot imagine that the motor is intended to get that hot.  Does it have a cooling fan on the end (you should be able to see by removing the bottom inspection plate) ?  Is the fan damaged ?  Are you running a 115v American machine on a British 230v supply ?  That would certainly heat the motor up, and eventually burn it out.  Just a few thoughts !

 

03-10-2025 05:14:26  #3


Re: Smith Corona 5Te Transformer Temperature

The fan blades are part of the motor and are clean. I'm in the US so the power supply is correct. The motor itself isn't getting this hot, but rather the transformer connected to the mains wiring. More specifically, this plate which appears to be a heat sink:

     Thread Starter
 

03-10-2025 09:32:10  #4


Re: Smith Corona 5Te Transformer Temperature

I have a 5TE in my collection and the transformer does not run hot, even when I use it for 2-3 hours at a time.

Have you used compressed air to blow out around the transformer windings ?

Also...the electrical wires of the windings might be breaking down with age and could be the cause for abnormal heat levels.

This article (below) is about power transformers in general but has some good info. about them running hot.

I would not leave the typewriter plugged in when not being used and you are not nearby.

It might be time to look for a parts machine if you want to keep your machine safely on the road.
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https://engineerfix.com/electrical/transformers/why-do-transformers-get-hot-and-how-to-avoid-it/

 

03-10-2025 22:40:14  #5


Re: Smith Corona 5Te Transformer Temperature

Thanks! I took it all apart tonight and it was very clean. Blew it out for good measure and no difference. It's still drawing 34 watts and half an amp. IR sensor is saying the bottom plate is 125F after about 15 minutes of use.

Guess I'll try to find a parts machine. The 5Te isn't cheap these days.

For what it's worth I did ask Phoenix Typewriter and he said they run hot, hot.

     Thread Starter
 

04-10-2025 10:22:25  #6


Re: Smith Corona 5Te Transformer Temperature

Ran my machine for 2-2.5 hours last night.  My IR scan indicated 103-104* F. at the end.
 Mine comes from 1960.
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05-10-2025 08:37:09  #7


Re: Smith Corona 5Te Transformer Temperature

Thanks for the data point, Pete! Keeping my eye out for a parts machine and will limit use of the 5Te for now.

     Thread Starter
 

06-10-2025 09:20:23  #8


Re: Smith Corona 5Te Transformer Temperature

It is odd how S-C did not leave more of an air-space under the metal cover (heat sink) of the step-down transformer.  A bit taller rubber feet could have accomplished that.

Having a thick felt typing pad under the 5TE would seem to make things worse in terms of heat build-ups.
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