Creating cheap custom power transformers by reusing a microwave oven transformer

Microwave oven transformers can easily be found discarded and reused to make a powerful custom transformer.  The ability to easily reuse the transformer comes from the primary and secondary windings being physically isolated from each other on the metal core.

The aim is to remove the secondary windings as cleanly as possible and wind a custom winding using enameled wire.  In my case for every one loop around the core gets one volt, the thicker the wire, the more current that can be supplied.

There are three windings on a microwave transformer, one primary and two secondaries.  In the pictures below, the primary is on the bottom and the secondaries are on the top.
The primary has hundreds of turns of thicker wire, do not modify this, keep it pristine.
The high voltage secondary, with thousands of turns of fine wire, we do not need this.
The six volt filament winding made from cloth insulated wire, we do not need this.

Removing the secondary is relatively easy. 

  • Clamp the transformer in a vice and using a hacksaw, cut one end of the secondary off.  Be careful that the saw does not cut into the primary at the end and try to avoid cutting the paper inner paper insulator.
  • Spray penetrating oil into the exposed wire in the transformer, this will help in the next stage.
  • Using a large drift and hammer, bash out the rest of the wire a bit from both sides at a time until it comes out like a horseshoe.  If the drift is too small, it will compress the wire and make it impossible to remove easily.
  • Once removed, clean all metal filings and make sure that the mylar paper insulator is intact, repair using insulating tape if required.  You do not want exposed metal cutting into the wire while winding.
  • Now using enameled wire, rewind to your own specifications.  The image below is a 4 volt ugly monster with several windings in parallel.

Remember that this transformer will hum like a microwave when in use.  It will draw lots of power. 
It will require some kind of forced air cooling to keep it happy.  Reuse the microwave fan…
Don’t attempt to take the laminations apart.  They are often welded. 
Best to source a transformer from a larger microwave oven, bigger = more power.

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Fixing a Noisy Kodak Ektapro Slide Projector Fan Repair

The Kodak Ektapro is the most “modern” slide projector around.  It is semi professional and costed big buck in their hey day.  Now due to the decline of mainstream use they are more commonly being found amateur photography people.

Kodak Ektapro

One fault that is found with an Ektapro is a noisy squealing fan, repairing it is a little tricky and requires a special tool (Long T-20 Driver).  A noisy fan is annoying or worse if it is not spinning you projector will be broken in no time.

Here are some quick instructions:

  • Remove the lamp module and the four screws from the bottom of the unit.
  • Remove the top cover by removing the focus knob and retracting the slide actuator arm.
  • Unclip the button pad and unscrew the screws for the intermediate chassis.  Remove the intermediate chassis.
  • The fan module should can now be removed, disconnect the cables.
  • Disassemble the fan by removing the two screws and pulling out the whole motor.  Unclip the clips on the the other end and everything should be apart.

Clean and grease these

Oil White Sponges in bearings

This sometimes fails

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How to suggest a feature on eBay

Who knows if there are monkeys operating the features section,  they are definitely in the tech support / customer support section.

Simply if you like to suggest a new feature on eBay:

1. Go to:
2. Click the ‘Send us your suggestion to improve the eBay site’ link. You may be asked to sign in.
3. Write your message explaining your suggestion and then click the Send button.

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Complaining to Coles Supermarket via Twitter Complaint AU

A while back Coles opened up a Twitter account (@Coles) which got flamed from the start.

They immediately abandoned it and it was desolate for some time, but it now seems that they are responding to their tweets trying to fix their “customer service”.

Using twitter to complain is a great way to vent your anger publicly, everyone can troll though the previous tweets and see what a others are complaining about.

Apart from twitter, there are other ways to complain, all of which are good to follow up on your public complaint with private details, such as name and address.
1800 455 400

@auspost is another well supported twitter page, where hundreds can complain and the rest of us can look down on Australia Post’s performance.

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