1980's electronic typewriter transformer bad?

A

atikovi

New Member
This is a Brother EM711 typewriter. It would randomly reboot as if you had turned the power off then on. Now it's totally dead. Took it apart and checked the transformer.



there is 120V on the black and white wires going up to the transformer, but only like 30 mV coming out on the two red wires on the left. Bad transformer? And where do I find a replacement? Found nothing by searching those numbers and have no idea what the output should be.
 
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I would have just ordered a 28-36v DC power supply brick.

 
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atikovi said:
That's not going to fit where the transformer is located.
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That's why you'd add a 5.5x2.1mm barrel connector and leave the brick outside your typewriter. Then you don't need to worry about an expensive and large capacitor. You can likely eliminate it or replace it with a much smaller one when needed.
 
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Hmmm. I'm counting on my fingers and I'm no accountant but:

Transformer: $15
+
Cap, 10000uf, <$10
50 volts*

Seems to be less than:

Digikey DC Supply: $33

and it preserves the original one piece operation of the typewriter.

* may or may not need replacement at some point.
 
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And with the brick, you get all the short-circuit interruption and voltage surge protection of a modern power supply. User's choice. Dollars aren't everything. It's the same advice as I gave in post #30. Cheers.
 
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ZipZapOuch said:
Let it run for a while and feel those aluminum heat sinks - can you keep your fingers on them?
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And lick your finger before you touch them

You should always do this, as if it's hot you will instantly hear the saliva 'boiling' - so can remove your finger before it's burnt. With a dry finger, if it's hot, your finger burns before you can feel the heat - the bodies heat sensing is a very slow action.
 
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