This time we will be taking a look at a Black and Decker model T2707SKT Toaster. Not that I was looking for a toaster to teardown but I just happened to stumble across it at my local XS Cargo store. It was a factory reconditioned unit that was then returned. The issue listed on the ticket was that one side didn’t heat properly. The regular price was around $30 or so and it was sitting on the discount shelf for $2. I figured it would make for a good teardown and possibly repair video.
Turns out the design of the toaster is both quite simple and more complex than I would have expected. Let me explain… The actual electrical design of the basic toaster is very simply. There is a large plastic plunger that is connected to the handle that gets pressed down by the user to push the toast down. When pressed there are 2 contacts that are made which transfers the electrical connection from both neutral and hot AC lines to the heating elements. The heating elements consist of one circuit for the outer heating and one for inner heating. Turns out that the inner one was working and the outer one was not.
There is an electromagnet that is used to hold the spring loaded mechanism in the depressed (toasting) position and when de-energized the toast pops up and automatically kills the power to the entire circuit.
There is not much in the way of protection in this device, the chassis is not grounded like many other devices like this. This means that if there is a stray connection from one of the heating lines to an internal metal component the case could be energized. The construction is quite well designed to prevent this though. I would have felt safer if there was a ground connection to the exposed metal housing though. There is also no over temperature sensors that could be seen in this device. Most high wattage devices that generate lots of heat have an internal in line heat sensor that opens at a pre-determined temperature to prevent an over heating issue from becoming dangerous. For example if something accidentally jammed the toaster in the depressed position it would eventually reach a temperature to turn off. I guess with this design the actual heating wires might fail after a short enough time to prevent any dangerous conditions.
The control board is powered in an interesting way. The heating coil for the internal section is tapped at around 12 volts to power the control board, this prevents them needing to design a circuit that first needs to reduce the 110V AC to a usable voltage. The only method of control that the control board has is to energize and de-energize the electromagnet that holds the toast tray down. There is no temperature feedback and the only output that the controller can provide is how long the heat is on. There is a large temperature dial and 4 push buttons but in the end all these do is vary the on time blindly. For some reason I felt that there was going to be some additional smarts in place here. **UPDATE** Alex left a comment about the control chip. I didn’t take a second look at it, I figured it would have been some type of generic timer chip. Was I ever wrong, the chip is a Holtek HT46R005 which is a microcontroller!
Turns out that one of the connections between the heating element and crimp connection was where it failed. This is a failure that can’t be repaired since this connection can’t be soldered due to the natural high temperatures of the connection. It would need to be spot welded or crimped. I don’t have a spot welding machine and there is no room to re-crimp so I simply temporarily twisted a binding wire around the broken connection using some light gauge solid copper wire to allow the system to be tested before it was thrown out.
During the teardown of the unit it was noticed that the AC power cord was squished quite badly in the strain relief clamp. This clamp is a simple piece of plastic that is held in place over a notch in the molded plastic base by 2 screws. I am not sure if this is an isolated incident where the cord is damaged to this extent by being held in place or if this is how most of the cables look after being squished in place. You can see some pictures of this below.
Unfortunately there isn’t much in this unit that can be scavenged. The electromagnet and timer board is the only thing that is of any interest.
You can see the damaged cord below, this was damaged by the strain relief clamp! See additional pictures of the damage in the picture gallery below.
Thanks to Spy Tec for sending the Zetta Z12 Spy Camera in for review. The unit is nice and small, the battery is designed to last long enough to catch the video you need. There are lots of uses for this device, if you have someone that is borrowing your morning paper or leaving your doggy presents on your lawn you can hide this little device to catch the action you need. Unlike a normal security camera you can set it up to just record when there is some activity to be recorded. There is a ton of other activation modes to help you record what you need. To see it in action watch the video below.
Pictures of the device are below, if you would like to see them in full size you can grab those here.
Thanks to Creative for sending in the Sound Blaster Roar for review. Right out of the box the quality of construction is evident. The feel of the buttons and switches is top notch, it should provide years of trouble free use. It is easy to pair it to your bluetooth compatible phone and get your tunes cranking on the Roar. If you don’t want to play music through your phone you can select one of the many other methods of playback. Pop in a micro SD card with some music will allow you to keep it standalone and play all of your favorite music. If you have a device that just has a headphone jack out like an old iPod that will work using the Aux in jack. The micro USB port can be used to play music from your computer.
The system has 3 active drivers, one is a long through woofer for surprisingly deep base. There are also 2 forward facing speakers for right and left audio, 2 additional passive radiating drivers fire music out of the side grills.
If you have a cell phone that needs a quick charge you can plug it into the full size USB port. The port has a 1 amp rating so it will also charge most tablets.
Need a conference room speaker? The Roar actually does a good job of transmitting the sound from your cell phone to the speaker and transmits the room audio using the built in room mic. The system is obviously doing a good job of canceling out the sound that it is producing in this mode since there is no feedback.
If you are feeling a bit uneasy in your surroundings you can arm the alarm and press the siren button to grab the attention of everyone around.
You can see that there are good and bad qualities to this device. That being said the good far outweigh the bad. If you are looking for a kick ass portable audio player to fill a room with booming sound this device is for you!
Thanks to GearBest for sending in this Opus BT-C3100 V2.0 Intelligent Battery Charger for review. at a quick glance this charger might look like any other charger that you see at the grocery store. Your generic store bought brand probably also has 4 charging bays for AA and AAA batteries, it probably has 2 charging circuits which places 2 cells in series to charge them, it most likely has 2 charging lights which just turns off when charging is done. If you leave the batteries in your generic charger you will most likely have batteries that have been overcharging or running down. Also your generic charger can probably just charge one chemistry of battery.
When you have a closer look at the Opus BT-C3100 V2.0 Intelligent Battery Charger you can see how this system differs from your every day generic battery charger. It can auto detect and charge NiCd, NiMH and Li-ion batteries. It charges each cell independently preventing bad cells from interfering from other cells from charging properly. Forget charging lights, this has a full LCD display that provides tons of status. It will monitor batteries that are left in the charger and keep them topped up and ready to go. From here the features go on and on. Don’t let the small package fool you, there is a ton of smarts and features built into this small package.
Have a look at the pictures below and in the video for a look inside the charger. The construction is a dual sided SMD load, the construction looks very professional. The battery contact spring tensioners work well and the connection to the PCB has been beefed up with a thick metal bar. The heat management in the unit is great, there are no hot spots when operating and if there was a problem one of the 6 thermal sensors would be sure to catch it. The processing and display is done using a chip on board which can be seen under the epoxy blob in the pictures.
The case is well built and feels nice in the hand, the buttons and battery sliders feel like they will last. The plug in power supply came with an adapter which changed it from a European plug to a North American style but this caused the plug stack to be quite long and might cause a problem if it was to be plugged into a wall plug. I was using a bench mounted power supply so I didn’t have any issues but this could be a concern.
The price of this unit is a bit higher than your grocery store version but don’t be fooled, this unit is worth it. Best of all GearBest is offering all Hacked Gadgets readers an 8% discount using the coupon code Anna08.
There is a fantastic display screen on this unit. The LCD screen is backlit when you are pressing buttons and is clear and easy to read. The screen is divided into 4 equal sections, one for each battery in the unit.The upper unit of the display tells you what function is being performed, the lower section is for data such as cell voltage, charging current, discharge current, etc.
You can use the slot button to select each of the 4 battery bays to adjust what operation is to be performed on that bay. This adds flexibility since now you can perform any task you like in any of the positions. For example you could charge cell 1 at 500mA, charge cell 2 at 1A, discharge cell 3 to put it into storage and do a discharge refresh on cell 4. You can also easily opt to perform the same function on all slots with the press of a button.
In charge mode you simply pop in a battery, you will be shown the initial battery voltage before the charge starts. You can then select the current you wish to charge the cell at.
In Discharge mode you can discharge the inserted battery to a preset level. You will also be shown how many energy was discharged from the cell after the discharge is done. It is then trickle charged to prevent it discharging any further.
In Refresh mode the charger will discharge and charge the battery 3 times to allow old batteries that have not been used in a long time to restore some of their capacity. After the 3 cycles are complete you will be able to see the total mAH of the cell. This lets you track the health of the battery over time if you like.
Test mode checks the capacity of the battery by immediately discharging the battery after it is charged.
Quick Test allows for a check of the internal resistance of the battery. This test is quick (under 10 seconds) and will show you if the battery is a good contender for high current applications. You can test batteries with other chemistries using this function such as alkaline and any other 1.5 volt battery.
I wanted an in-circuit ESR meter (equivalent series resistance meter) to aid in determining the condition of electrolytic capacitors without the need of desoldering them first. When capacitors fail you will often have some signs of failure such as bulging of the capacitor top. Starting in approximately 2002 and continuing till about 2010 there was a glut of high failure rate capacitors on the market which found their way into everyday items such as PC power supplies, monitors, motherboards etc. These devices would test fine after manufacturer and continue to work for the consumer for many years but fail prematurely, often in as little as one year.
I purchased a MESR-100 Meter from eBay for around $55 USD shipped to my door in Winnipeg (Canada). The meter came well packaged in a retail box, this is a nice change from many other items from China that are simply wrapped in bubble wrap and stuffed into a padded envelope. Inside the box was the meter, two short meter leads and a manual. Pressing the red power button for a few seconds powers the meter, it is ready to use after about 3 seconds. The display is a backlit LCD display, it does appear that the backlight is on all the time. The display is nice and bright and has a good viewing angle, there are two hot spots near the bottom of the display which is probably due to the location of the backlight LEDs but it doesn’t effect display readability.
The meter has 3 modes, autoranging, 0 to 1 ohm, 1 to 10 ohm and 10 to 100 ohm. The modes can be cycled through by pressing the mode range button. The meter can be zero calibrated by shorting the leads and pressing the zero button. All of the buttons need to be pressed for about half a second before they are recognized, a quick tap isn’t usually sufficient. This button sensitivity could be improved but other than powering the unit on I am thinking it will live in automatic mode until it is switched off after use anyway.
The display has lots of useful information. There is a battery indication, mode indication, large resistance reading and some smart text under the reading that indicates some criteria of when the capacitor under test would be considered good. There is also a chart on front of the meter but the automatic text output during the reading is very convenient.
The meter is powered by a PIC18F24K20 microcontroller, there are also some unpopulated areas which suggests that there might be a more advanced version of this meter available. The other main IC on the board is a TI LMV824 Precision Low Voltage Operational Amplifier. The case also has some indications of a second version, directly under the 3 existing buttons you can see a space for 3 more, it is obvious from the inside of the case and is also slightly visible when looking at the front of the meter.
The meter case could be improved, it is cheap feeling and the tilting bail works but feels like it will break in time with normal use. The display protection is quite thin and you can feel it deform easily with a light press. The cutout on the side for the external USB jack is not centered very well adding to the low quality look and feel of the case. I wouldn’t have this thing unprotected in a toolbox since the case would be prone to damage in that scenario.
The PCB is of high quality, it is a single side SMD loaded board. The PCB has an immersion gold finish which should keep it corrosion free for a long time. The solder joints look good, there is some hand soldering of the leads that run to the battery compartment and the front test jacks, these could have been soldered better but they are adequate, it was nice to see some heavy wire going to the banana jacks on the front but their placement made it cumbersome to re-assemble the meter since the plugable area is between where the leads are soldered into the board and the jack, this means you need to bend the wires around the plugable area while reassembly. There is one bodge on the board, it looks like a lower profile capacitor was originally specified but when it was manufactured the capacitor that was used was slightly too tall so it was soldered in and allowed to lay against the PCB for clearance. You can see it in the pictures below and in the video.
The reading are believable but I don’t have any other test equipment on hand that can confirm if the ESR readings are accurate, the manual does indicate that the meter is accurate to 1% and 2% depending on the range you are in. The meter states that it uses a 100KHz frequency to test the capacitors using a sign wave and this was confirmed on the scope, the test voltage is around 150mV.
Overall I am pleased with the meter, for the price the functionality. If you are looking for a meter in this price range I would recommend it.
You can see full sized images here on Flickr.
When you are taking apart some electronics to start a repair a normal screwdriver will work but a battery operated one will make the job go faster. Thanks for Black and Decker for sending in this Gyro Screwdriver for review. I have used battery operated screwdrivers before but nothing with the technology that this one is packing. To operate it all you need to do is squeeze the handle of the screwdriver which will depress the large button at the base. As soon as it is squeezed that is considered the starting position, at this point the bit will not be turned, as you turn it in one direction or the other the bit will follow. The further you twist the screwdriver the faster the bit will be turned. The drill can accept any standard bit, but the unit comes with a flat blade and phillips to get you started. If you are interested to see what is on the inside be sure to checkout the Black and Decker Gyro Screwdriver Teardown.
The drill have a built in LED light that turns on when it is in use, the light also functions as an indication for conditions such as low charge and over heating. There is no charge indication though and it would have been nice to have the LED flash once ever 3 or 4 seconds to indicate that the charge cable is plugged in properly and the unit is charging.
Probably the best news here is the battery, the lithium technology will last on the shelf for months and still be ready for use. I hate grabbing a tool for use just to realize that I need to charge it for many hours before I can use it.
The screwdriver was tested by screwing a drywall screw into plywood, it performed the task but struggled a bit. This shows that the screwdriver has quite a bit of power since this task would normally have been done using a full sized drill. Fastening threaded screws was very easy for the screwdriver and I suspect it could drive these all day long.
The feel of the tool is not bad but could be contoured a bit differently to feel better in my hand. The movement based operation does take some getting used to, for someone who has always used button based tools it doesn’t feel as controllable as the manual style for me. This would probably change with more use though.
For full sized images please see them here.
Thanks to Circuit Specialists for sending in this 3 chanel power supply. The Hantek PPS 2320A sure packs in a ton of features for the price. The video below goes through the unboxing of the power supply and a quick run through its features. Overall it functions quite well, there are a few questions that need some clarification. I will have a look through the manual and reach out to the guys over at Circuit Specialists if I can’t find the answers.