Typewriter Talk / Smith Corona 5Te Transformer Temperature

**Posted by DrLoveWizard** 02-10-2025 20:34:03

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.

**Posted by thetypewriterman** 03-10-2025 03:29:14

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 !

**Posted by DrLoveWizard** 03-10-2025 05:14:26

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:

**Posted by Pete E.** 03-10-2025 09:32:10

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/

**Posted by DrLoveWizard** 03-10-2025 22:40:14

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.

**Posted by Pete E.** 04-10-2025 10:22:25

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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**Posted by DrLoveWizard** 05-10-2025 08:37:09

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

**Posted by Pete E.** 06-10-2025 09:20:23

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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**Posted by Paul1986** 22-10-2025 18:51:23

Hello DrLoveWizar,
If the transformer feels too hot to touch comfortably, i.e. you can´t hold it for more than a few seconds, yes, you probably have a problem.
Things to look out for: 1) dying electrolyctic capacitors. Does your machine have any large capacitors? As the electrolytic fluid inside dries out, the capacitor's internal resistance increases, causing it to overheat, which in turn heats the transformer. 2) insulation breakdown. the insulation of the transformer windings deteriorates over time, causing micro short circuits within the transformer. 3) sticky or failing mechanical components: gummed up parts make the motor work harder, draw more current, which in turn makes the transformer 'sweat'.

**Posted by DrLoveWizard** 22-10-2025 19:56:01

There are no large capacitors. It's just mains wiring, connected to a transformer, connected to on/off switch, connected to a motor. The machine is in pristine condition and I've replaced the belts. Don't think the motor is working any harder than it normally would. Likely insulation breakdown or something in the transformer itself. I didn't pull off the tape around the transformer because I wasn't sure if it would have asbestos in it.

For what it's worth, I acquired a spare motor from TB Writers Plus and swapped it out. Had the same exact issue unfortunately.