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.
I ordered a cheap solder pot from Ebay a few months ago. I didn’t want to spend a fortune since I will only need it 5 or 10 times a year, just to take care of the jobs where using a soldering iron to tin a bunch of wires would be a pain. I had used it 4 or 5 times prior to this review and was very surprised at the quality of case construction, look and feel of the controls, and the speed at which it could melt solder. The only thing I would have liked is the power cable to exit the rear of the case and the on off switch to be pushed up to turn on. As I write this I am thinking the easiest way to solve all of these problems is to have the text on the label printed upside down so that the temperature dial, on/off switch and power cord were naturally positioned on the top. I bet that the guy who designed the case and physical layout was not the same guy who designed the label.
I was expecting to be pleasantly surprised at some nice build quality on the inside, but once the cover came off I lost some faith in the unit. I can see that this was assembled in a hurry like lots of other Chinese products. There is some heat resistant insulation covering the feed wires for the heating element, as you can see in the pictures and video a small sleeve should have been long enough to safely nest itself under the larger sleeve but in this case the wire was too long which left the insulation too short and exposing one of the conductors.
There are some very poor connections of two very important wires to the small control board. One is the live feed direct from the plug, it is just soldered to the rear of the board onto the fuse holder solder point. It looks like originally it would have been through hole mounted from the front of the board into the same position and a smaller fuse holder (or solder in fuse) would have been used. If this wire comes loose and brushes against the inside of the case you will see a light show for a few seconds before your house breaker trips.
The other very poor connections were on both ends of the heater. There was a push on lug that was poorly soldered to the center terminal of the on/off switch. After the review a small wiggle was all it took to pop it off. When pushed onto the terminal the height of the lug interfered with the back panel, the simply solution was to simply fold the connector over on itself. The other heater connection was to the control board and this was also simply tack soldered to the back of the board just waiting to vibrate loose, looks like this connection also had a lug on it at one time but the lug was simply trimmed to a small nub which was the part soldered to the board.
If anyone is interested the triac used in the design is a BT137-600E. There is line voltage connected to the potentiometer which feels wrong to me but with a quick glance at a similar product, it looks like you can put 250 volts on many of these little pots (such as this one [PDF]). I guess I have seen too many loose adjustment pots with missing knobs which would make me think twice about adjusting them if I knew there was serious voltage on the wipers of the pot.
I also saw a problem with the switch wiring that wasn’t there (in the video). Many of these switches have a common terminal in the center, when the switch is flipped up the center and lower terminals are shorted and when the switch is down the center and upper terminals are shorted. In this case when the switch is in the off position there is no connection between any of the terminals. When moved to the on position neutral is placed on the center terminal which has one of the heater leads attached to it and also an internal lamp connection. The hot for the lamp is connected with a jumper from the fused side of line voltage on the control board.
Thanks to Black and Decker for sending in this 20V Lithium Drill for review. This drill would be perfect for the average DIYer who is tinkering with projects in the basement on the weekends and evenings. It is nice and light so you won’t need to work out at the gym before a session of drilling. That being said, if you are planning on building a deck or putting in a new fence this is not the drill for that. The most exciting claim is that it will hold a charge for up to 18 months. Of course there was no way I could test this claim in the 2 weeks that I have been playing with the drill.
The LED light is nice if you are using it in a dark corner, it automatically turns on whenever the drill is being used. A few days ago I assembled a new corner desk for my daughter, this thing was a beast of a desk with poor instructions which meant that 5 or 6 of the pieces needed to be unscrewed and rearranged to work properly. I would have thrown in the towel if I was putting it together by hand. The clutch worked well for this job, I just set it at 3 and drove the screws in until the clutch kicked in.
Remember the first Mini Weapons of Mass Destruction? John Austin is back at it with a new version of the book called Mini Weapons of Mass Destruction 2 – Build a Secret Agent Arsenal. This book boasts over 250 pages of fun builds.
The projects are well laid out as usual, there are lots of great step by step projects with nice black and white pictures. The pictures remind me of the ones that accompany assembly required furniture. You should be able to follow the pictures to build the creations and refer to the documentation if you need clarification.
Chapter 1 is my favorite, it has 8 Agent Sidearm projects. The PPK Tic Tac and the Binder Beretta 92 look great, best of all you probably have everything you need to build these around the house already. The main parts of these two weapons is a box of Tic Tac breath mints, binder clips, paper clips, party balloons, markers and tape.
You better keep a close eye on your office mates book shelf, if you see a copy of this book you better watch your back since you can be sure a sneak attack is eminent. Better yet get your own copy and plan a counter attack. 🙂
Our friend Csaba did a great Review of the SIGLENT SDS1102CM Oscilloscope.
Based on the CSV file:
Model Number: SDS1102CM
Serial Number: SDS00002111512
Software Version: 3.01.01.22
Based on the turn on screen:
Software Version: 3.01.01.223
Approx. 450USD on ebay.com”