Using Nichrome Wire To Repair Broken Plastic Parts

February 5, 2013 by Mike Szczys 44 Comments

nichrome-wire-plastic-repair

It’s a real bummer when injection molded plastic parts break. We’ve never found a gluing technique that works for a part which is exposed to force like the clamp on this camera tripod. But [Matthias Wandel] may be on to something. Here he’s using nichrome wire to reinforce the broken plastic part.

The repair process is demonstrated in full in the video after the break. He scavenged the wire from the heating element of broken hair driers. the idea is to wrap the wire across the broken piece, then apply power from a bench supply. This heats the wire, which can then be pulled beneath the surface of the plastic. [Matthias] likens it to using rebar in concrete.

His implementation could be improved just a bit. Getting the wire to embed evenly is a problem, but using a pair of pliers instead of just alligator clips may yield better results.

Continue reading “Using Nichrome Wire To Repair Broken Plastic Parts” →

Laminated Wooden Case Brings A Dropped Coffee Grinder Back From The Junk Heap

January 21, 2013 by Mike Szczys 14 Comments

coffee-grinder-fix

Instead of giving it up for dead, [Suprise Pink Mist] fabricated a replacement case for the motor and blade of his broken coffee grinder. The original enclosure was made of plastic, which didn’t survive being dropped. There isn’t an image of what those plastic parts looked like, but we have to think they were nowhere near as neat as the replacement.

The first step was to cut a set of plywood discs to the approximate outside dimensions. Since the base of the motor has several different diameters each disc had a void cut out of its center to match. The image to the right shows the motor sitting upside down next to the stacked plywood. The black electrical tape seals around the mason jar ring which was a perfect friction fit with the original bowl of the grinder. Once everything was glued together the outside edges were flattened on a belt sander and the mason jar was screwed in place to house the beans during grinding.

[via Reddit]

Replacement Drivers For Old LED Signs

January 11, 2013 by Mike Szczys 17 Comments

led-sign-driver-replacement

The LED signs sitting idle on the left are brought to life by an Arduino replacement driver shown to the right. The big one is made by Signature Electronic and used as an advertising display like you would see in front of a business. [Bob Davis] picked it up on eBay being sold as non-working. After some power supply repair he set to the task of driving them with his own hardware.

The images he shared give us a good look at the parts used on the sign. The display area is made up of a set of eight 8×5 pixel LED modules. Each module has a key and slot in the top and bottom to help align the rows properly when building a larger array. They use TPIC6B595 shift registers (the same ones seen in yesterday’s low-res gaming hack) and 74HCT138 decoders to multiplex the pixels. Most of this info is shared in the second part of his post.

He hasn’t quite gotten the larger sign to run properly. Each row displays the same data but one pixel lower than the last. If you’ve got some insight on why this is happening we’re sure he’d like to hear about it.

[via Dangerous Prototypes]

Electric Clothes Drier Repair Heats Things Up

December 18, 2012 by Mike Szczys 33 Comments

clothes-dryer-fix

[How To Lou] sure has shown us how to do quite a few things. This time he’s dealing with an electric clothes dryer that won’t heat. We’ve been elbow deep in our own appliances and we think [Lou’s] matter-of-fact demonstration will help you gain the confidence to investigate problems before deciding if it’s a job to be relegated to the repair man.

This picture shows the back side of a clothes dryer after having a protective panel removed. Just out of frame is a functional schematic which lists each part and it’s resistance measurement. Lou has labelled those parts in this image to help us understand what we’re looking at. In the video after the break he begins doing the same troubleshooting that a repair would use. He grabbed his multimeter and used it to test the resistance of each component after removing the wires from it. All of them should read zero Ohms except for the heater coil which the schematic rates at 7.8-11.8 Ohms. The high limit thermostat is loose and measures an infinite resistance. This, coupled with the charred wire on one side is the culprit. As with that ice maker repair from yesterday, [Lou] searches for the numbers on the part to find the replacement he needs.

Continue reading “Electric Clothes Drier Repair Heats Things Up” →

Repair Your Ice Maker Motor Without Buying A Whole New Assembly

December 17, 2012 by Mike Szczys 28 Comments

ice-maker-repair

There are a number of things that can go wrong with an automatic ice maker. But one of the more common problems is that the motor which scoops the ice out of the integrated trays can burn out after years of use. [Dave] recently repaired a common ice maker motor and shows us how cheap and easy it can be. See how he did it in the video after the break.

Pictured above is the motor and gear box from the ice maker. Before disassembly he verified that the problem is with the motor by placing a piece of paper in the path of the fingers that move the newly formed ice. After removing the sensor arm and three screws he was able to pull this front portion from the unit. The two wires are clipped as near to the motor as possible and the motor itself comes out with just a twist. After verifying that the gears are not broken he sourced a $2.50 motor replacement by Googling the part number (M004 3W in this case). Once the new unit arrived the motor wires are connect in much the same way that a punch down Ethernet jack makes a connecting with insulated wires.

This is something worth looking into if your ice maker is not working. The manufacturer may suggest replacing the entire unit which can be well north of a hundred bucks… this is a worthwhile gambit to save some cash. Well, we guess you could always build your own non-electrical ice maker.

Continue reading “Repair Your Ice Maker Motor Without Buying A Whole New Assembly” →

Repairing A Junked Signal Generator

October 15, 2012 by Mike Szczys 21 Comments

We must be walking past the wrong dumpsters because we certainly haven’t encountered equipment like this just waiting to be salvaged. [Shahriar] found an HP 8648C Synthesized Signal Generator while he was ‘dumpster diving’ and set out to fix the malfunctioning lab equipment. He posted a 1-hour video on the project, which you can find embedded after the break. The actual fix happens in the first half, the rest of the video is spent testing the resurrected device.

The back corner of the case has been dented, which may be the reason this has been thrown out. When it is first powered it emits an unpleasant screeching noise and the user interface doesn’t do anything. [Shahriar] says he recognizes the sound as a malfunctioning switch-mode power supply. Sure enough, when disconnected from the main board it still makes the noise. It turns out there’s a huge electrolytic capacitor the size of a stack of poker chips which has come loose from the PSU board. When it’s resoldered the device fires up as expected.

Now how are we going to find a digital capture oscilloscope that just needs to have its PSU reassembled?

Continue reading “Repairing A Junked Signal Generator” →

Oscilloscope VFD Repair Like Doing Brain Surgery On Yourself

October 9, 2012 by Mike Szczys 11 Comments

[Jerry Pommer] has an old Tektronix 2236 that is having some issues. Just to the right of the top corner of the screen is a VFD display that is used to show various numerical measurements. Unfortunately this has stopped working, so he made the oscilloscope probe itself in order to trouble-shoot the situation.

The entire repair process was filmed and you can see the 42-minute job embedded after the break. There’s a lot of stuff crammed inside that oscilloscope, and we see a tour of it all at the beginning of the video. Once [Jerry] gets down to business he traces the problem to a JK Flip-Flop used to feed the display. The output appears correct at first, but the clock signal is not functioning as expected. His solution is to use an MSP430 chip to replace the Flip-Flop functions.

The confidence to try this repair was sparked by [Todd Harrington’s] car-stereo VFD repair video.

Continue reading “Oscilloscope VFD Repair Like Doing Brain Surgery On Yourself” →