Tuesday, December 23, 2014

DIY 3D Printer - Printing Small Parts

Here is a picture of a printed 3D hand.  When I first tried to print it I had fingers flying all over the place.  I even tried gluing them down to no avail!

Here is what you can do to make printing small parts possible.
1. Clean the glass with a razor blade.
2. Treat the glass with acetone and/or hair spray.
3. Print a 3mm "Brim" around the base of objects.
4. Print the center or "infill" first, then the edges.
5. Use a soldering iron if needed to remove "bumps".
6. Slow down the acceleration to 1000 or 2000.

Here is a video of the results.
http://youtu.be/6_5nY8F2hQg?list=UU49j5FVUO2KIFyH2IXmGXjg

The problem is that the plastic expands in the Z axis as it cools.  Then when the print head goes over it the part is impacted and sent flying.  If the "infill" is printed first then the edge does not need to be passed over to print the infill.

Wednesday, December 10, 2014

EcoQuest Fresh Air II air purifier repair

I have purchased some junk EcoQuest Fresh Air air purifiers to repair.  I fixed one by replacing the capacitors in the power supply.  I like these air purifiers because they feature an Ozone maker, and Ionizer a UV light (to kill germs) and a normal air filter too!

I have two of these air purifiers that I cannot fix.  They come in two versions.  Version one has a 12 volt switching power supply in the lower left corner.  Then there are three Triacs in the middle that turn power on to the devices.  Then there is a 5 volt regulator over on the right side that powers the logic circuits.  On mine the IC for the 12 volt power supply blew up.  I tried taking a 12 volt AC adapter and powering it up that way.  The green LED comes on indicating that the 5 volt power supply is working.  However the LCD powers up but remains blank.

I labeled the parts in this picture.


My other air purifier is a version two device.  It uses a telephone cord or a SATA cable to connect the LCD Display.  The power supply in the front left corner only puts out about 2 volts and gets very hot. In this model the switching power supply makes 8 VDC, 12 VDC and 40 VDC.  The test points for these are located just above the power supply transformer that is covered in metal in the picture below.

This is a close up showing the power supply test points.

Once again I used an AC adapter to provide 12 volts and 8 volts but it would not power up even then.  However the AC adapter was not loaded down indicating that the switching power supply is at fault.

Does anyone have schematics or anything that would help me in fixing these?

Monday, November 24, 2014

MY DIY 3D Printer update

Here are a couple of tricks I have learned.  When I first started printing everything worked fine.  Then after making about 5 things they started coming loose.  To clean the glass use nail polish remover (Acetone) on a Kleenex.  Then apply 2 or 3 squirts of hairspray.  You may need to spread it around a little.  That surface preparation results in the best adherence of the printed parts.

I have made several upgrades to my 3D printer.  Like for instance an oversize fiberglass Y axis carriage.


Here it is printing out a Mendel90 X axis motor end.  I am working on printing out all the parts of the Mendel90 3D printer.


I used some packaging strap to hold the ribbon cable up.

This is a picture of my new extruder's hot end.  I need to mount the fan to something but it has survived hanging from the wires for quite a while.  Here is a link to a video showing it in operation. http://youtu.be/MVh2b1nGNW8?list=UU49j5FVUO2KIFyH2IXmGXjg

Here is my growing collection of "Bricks".  Things that did not turn out like they were supposed to.  I have made far too many bricks, so now I built the new extruder and hot end.

Here is a link to my latest video.
http://youtu.be/nLawLOgIe3Y?list=UU49j5FVUO2KIFyH2IXmGXjg

Monday, November 17, 2014

Crown XTi 1000 power amplifier repair

Over the weekend I dissembled and repaired a Crown XTi-1000 amplifier.  The problem was caused by bad connections on a bridge rectifier located in the power supply section.

This is a close up of the bad connections.  The leads needed to be cleaned and re-soldered.

This is the corner of the board where the problem is found.

This is what the amplifier looks like with the cover removed.  You need to remove the front, then all the screws on the back, then all of the screws holding the board in place.  There are four screws holding the heat-sinks in place that are under the foam.


Tuesday, November 11, 2014

Chevy Cobalt Replacing the front door speakers

One of the first things I do when I buy something used is to make a list of things to repair.  On the car it is something like this:
1. Prime
2. Paint
3. Undercoat
4. Door locks stick
5. Snow tires
6. Front Speakers
7. Do Spider Spikes fit?

So far 1, 2, and 5 are fixed.  When it comes to the front speakers Pioneer actually makes speakers that fit.  You can also buy an adapter that will allow you to use any 6.5 inch speaker if you want.  The wiring adapter is not needed.  Just tin the wires and they will fit tightly into the jack that was connected to the old speaker.

The new speakers come with clips that need to be installed first as seen in the picture below.

To install the speaker first remove or pry out the door cover near the speaker.  There are three screws behind plastic snap in covers that you will need to remove to take the inside door cover off.  Remove one screw and the old speaker comes out.  Connect the wires for the new speaker.  The wires can be taped in place with electrical tape.

Put one side of the new speaker in and then rotate it up and down to catch the two clips on the opposite side.  Tighten up the screws.  Use duct tape to fill the gaps above and below the new speaker to block road noise.

You are done!  It only takes ten minutes to do.  Turn on the radio and make sure that the new speakers work.

Now I can actually hear the turn signals, as the sound comes through the speakers.  Hopefully the warning that the headlights were left on will work too.


Thursday, November 6, 2014

My New(er) car - a 2007 Chevy Cobalt

After 20 years of driving vans, I have made a drastic change.  I drive 45 miles to work every day and the cost of gas for the van was running around $5000 a year.  So I have bought a car that should get me about twice the gas mileage and save me the cost of the car every two years.  These pictures were taken right after I touched up the paint.  There were some rust spots on the fender around the rear tires.




So far the Cobalt is getting me around 34 MPG according to the built in mileage calculator.  I hope to make some minor changes to get that up to 40 MPG.