Something great showed up in the post, a package from Anatek with the Blue ESR meter kit.
I have been trying to get an LCD/LED TV set working. I was running into some problems in the diagnostics. Everyone I came across online that does TV work says the best tool for basic electronics diagnostics is an ESR meter, and the Blue ESR is an affordable ESR solution. As a kit, it’s $80 and worth its weight in gold.
There aren’t a lot of parts, so the kit is fairly simple to assemble. The assembly order is based on parts types, first the 1% resistors, then the 5% resistors, followed by capacitors then semiconductors and so on.
Getting the parts on the board goes quickly. My best recommendation to anyone building the kit is to take your time and be sure of each part and it’s placement.
Once all of the parts are are on the board it’s time to calibrate the meter. Calibration is easiest if you have a variable power supply for testing the low battery indicator, but you can get away without one. The assembly instructions include a simple circuit you can build for this test.
Calibrating the meter itself only requires the two resistors included with the kit for this purpose and the turning of two trim pots. I decided to take the calibration resistors and keep them stashed in the battery compartment for possible recalibration at a later date.
With everything calibrated and running well it’s time to button it all up. After buttoning it all up, it’s time to get back to that TV project.
Although the TV project is still pending, the Blue ESR is done. More to come on the TV in a future post.
If you don’t work with RF electronics the need for an L/C meter may not be readily apparent. If you work with RF, you have likely found capacitors and inductors in the junk pile and played hobb trying to figure out the value, unless of course they were marked.
If you wind your own inductors or make your own capacitors the need for an L/C meter is a no-brainer. I bought a cheap Chinese manufactured meter and it was no bueno. No redeeming qualities what-so-ever.
Being a homebrew ameture and a recycler of electronic components, I decided to buy the L/C Meter IIB kit and build it. The kit itself is very straight forward. Assembly is well documented and easy to follow.
I have been generating a lot of solder smoke lately so I may have an advantage here in assembly speed but I went from shipping box to functioning test equipment in about 4 hours.
Starting with full parts inventory I went right into construction. The parts list is only one sheet and it is very detailed. After checking in all of the parts and tagging them to the parts sheet I fired up the soldering iron and started melting metal. Filling the printed circuit board didn’t take long at all.
The only hiccough was technician error. I got all of the components soldered in, mounted the board in the back of the case, mounted the LCD, and plugged in the battery. When I turned on the power switch I got nothing. I knew from reading the instructions fancy that that a common oversight is that the contrast pot should be turned fully clockwise. When I went to check the pot I noticed something missing, I forgot to install the IC’s in the sockets. Doh!
After installing the IC’s I checked the pot and Voilà! A working L/C meter.
At $100 a kit that looks as simple as this one does you may be tempted to buy a cheaper factory assembled meter. I would strongly advise against it. A comparable factory manufactured meter will set you back at least twice what the L/C Meter IIB will, probably more.
I purchased a cheap meter for $38, paid $6 for shipping and another $8 to return it. Sure, it looks nice but it is complete garbage.
And if you need something else to push you over the fence on this purchasing decision, buying from AADE supports a family run US business that takes pride in the work they do. Now that’s a bargain at any price.
Solder smoke is filling the air as I continue work on the 40 meter Beach 40 DSB transceiver so check the build page for updates. I will be making an update tomorrow!
The Newcason XC4070L Handheld LCR Meter I ordered showed up on Monday. Wow, what a disappointment. No stability in measurements whatsoever and I’m not talking bounce between two consecutive numbers. 32 ρF to 64 ρF on a 50 ρF capacitor which by the way I checked with another meter that pegged it at 49 ρF. This puppy is on the express return train.
I did get something good done while testing the meter. I wanted to make a set of alligator clips on banana plugs to easily check through-the-board components. I wanted to make a set of these for some time. Now I have them.
One of the advantages of using these is that it reduces the inductance and capacitance errors that can be introduced by some meter cables and close proximity of hands.
In other pending order news, I have the tap and dies for the antenna. Of course I am waiting on the drills. So there the tap and dies sit, on the group W bench, just waiting on the for the drills.
As soon as I get the drills I should be able to get all of the antenna parts all connected up so I can start tuning and testing. Then I can move on to the ATU.
On Saturday I picked up a few things at the De Anza Electronics Flea Market. The most impressive acquisition would be the Lafayette Signal Generator for $20.
I have been needing one and I was dreading the prospect of having to build one and having a tough time without the right tools for calibrating it, so this was a great find and a steal of a value, though I didn’t know it for sure until today.
One thing I have learned about buying used electrical/electronic equipment, particularly in at a flea market, is that you have to take your time and open it up, get documentation, inspect and clean the equipment before attempting to use it, or plug it in for that matter.
Sunday was opening day. I noticed right away that I would need to replace the power cord grommet as it was in two pieces. I didn’t actually get to anything else until today.
Today I inspected all of the wiring and components, looked for hot spots and anything that would indicate an over heat. Having found nothing of the sort I moved on to cleaning, which there was surprisingly little to do. I made sure the tubes were cleaned and had no fingerprints on them. Now that I have a piece of tube equipment I will need to get a tube tester. 😉
With the cleaning done it was time for the plug-in and smoke tests. No pops and and no smoke! I let everything warm up and burn in for a good twenty minutes before starting any tests.
Testing with the oscilloscope began with the AF (audio frequency) side of the generator. After the twenty minute warm up period the “approximately 400 cycles” audio tone as specified in the manual turned out to be stable at 388 cycles (Hertz). I can work with that.
“kc” is kilocycles. The term is essentially the same as the more familiar kilohertz along with “mc” megacycles being the same as megahertz. The change over in terminology occurred slowly from the mid 70s to the mid 80s. Many hams still use kc and mc. I use them interchangeably depending what I am referencing or who I’m talking with. This piece of equipment has frequency labeled on the dial as kc and mc.
Moving on… The generator did its first diagnostics job with a portable amplifier I have had for a very long time (the one on the right). I clipped on the amp to the audio out and it turn out the volume control on the amp is trashed from banging around in my tool bags for a couple of decades so I will need to replace the potentiometer in that this weekend.
I then moved over to the RF (radio frequency) side of the generator and clipped on the oscilloscope. The RF side is divided into 5 switchable bands. I checked each band by referencing the frequency on the dial with the frequency on the O-scope. All five bands checked out very closely to the dial. A little lead or lag here-and-there, but overall pretty close for this equipment and its age which I’m guessing is about as old as me (made in the mid/late 60s).
The frequency counter I purchased last year has been giving me problems. New equipment, cheap (figuratively and cost), and no manual. With the help of the new sig gen and the oscilloscope I managed to fix a couple of minor problems and figure out the modes on the counter in the process. Looks like the electronics bench is finally coming together.
Now that I can check the receivers I build I can also check the transmitters I plan on building. I can also check portions of the radios as the construction moves forward. I plan on building more of my own test equipment but it’s nice to have a reference point or two to calibrate off of.
(2015-04-03 This page has been copied to projects)
This was the first attempt at an oscillator for practicing CW. I don’t remember where I found this particular schematic but there are a ton of oscillator circuit designs available online. Click here for a Google search that will result in a lot of options (over a half million hits!) The image results are a good place to start.
I committed to protoboarding this design because I wanted to play around with it some more. At the time I built it I was planning on getting an O-Scope but I didn’t have one yet. Now that I have one I can revisit the circuit.
The AF (Audio Frequency) tone is unstable to say the least. It varies from 3kHz to about 200Hz . The wave form resembles a square wave, but only loosely. It is very spiky and irregular.
While this is a simple circuit to build, uses only a few components, can be built very inexpensively, was a fun basic electronics project, and would be good as a beginners circuit / soldering project, I wouldn’t plan on using it for much more.
I would avoid it for a CW practice oscillator. If you are serious about learning CW, do it with a stable oscillator that will be pleasant to listen to. This thing can squeal at times.
Mark II – 555 IC Based Oscillator
As the section title above says, this oscillator is based on the 555 timer integrated circuit, a much more stable oscillator, also with few parts.
I documented the build on Flickr but the focus was more on the cabinet build and less on the electronics.
This circuit makes a good CW practice oscillator. Still a very easy build for beginners and fun. I was going for a steampunk look with the cabinet build. There are many things I think I would do differently in the cabinet build to make it easier, and smaller, but the oscillator works just fine as is.
The waveform is a pritty clean and produces a consistent 724.8 – 725.2 Hz tone. This circuit does consume more energy then the other. I put a fresh battery in the oscillator, had done a week of cw practice 20 minutes a day when life called and shelved it in May 2014. I just took it down and did some testing when the battery died.
Thing two I might change, a positive power cut off switch to completely lift the battery from the circuit. Just a thought.
Here is a short video of the cabinet and the oscillator in action with a CW key. There is no additional AF amplifier which brings up the one thing I might change. It my be a good idea to add a variable resistor on the output to adjust the volume.
There is a neat site Learning CW Online or LCWO.net I am just starting with. Since I am just starting with them I don’t have a whole lot to say about the site, but, it did spark a short project idea.
LCWO has different sections for copying code and for transmitting code. The copy side is easy, just listen through the speakers on the computer or headphones. Transmit requires action, you need to key something, usually the left mouse button. I have a touch pad and not a mouse. Besides, a mouse doesn’t have the feel of a straight key (SK) and that’s what I will be using on the radio…
Enter the idea… a USB cw key! I’m cheap and more homebrew so I came up with an incredably simple USB mouse mod that allows me to use the key with any site or program that will allow you to key by clicking on a virtual key.
All I did was open up the mouse ans solder two wires to the left mouse switch and run those wires out the side of the mouse case and tie them down to the binding posts on the straight key. Now the key is parallel to the switch. You can still use the mouse, and you can use the key too.
I still need to do one thing before this project is done. I need to install a jack in mouse so I can easily unplug the key when I just need a mouse.
Helpful Hint: If the mouse keep sliding around while you are trying to use the key, just line it up with the on-screen button and slowly pick it up and turn it on its back. This will stop it from tracking.