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So far aharpham has created 28 blog entries.
7 09, 2015

Hallicrafters S-38B Restoration – Part 6 Final

By | September 7th, 2015|Blog, Halicrafters|0 Comments

In the final installment of our restoration We show how we made the replacement knobs and give a final overview of the completed restoration.

One point I want to clarify.  In one of the videos I misspoke and it sounded like the chassis was not hot.  What I did was make sure it wasn’t hot when the power was turned off and then I also installed a safety cap to make sure if the filter cap failed it would not fail to a short.

Over all we are very happy with the outcome and think we did justice to this restoration.  We learned a lot and hope to apply those lesions to future restorations.

At our local August club meeting, we presented the restored radio to our friend and he seemed to be very happy with it.  We have several more Hallicrafters radios to restore, so look for future videos on those.


29 07, 2015

Hallicrafters S-38B Restoration – Part 5

By | July 29th, 2015|Blog, Halicrafters, Projects|0 Comments

In part 5 of our restoration project, we align the radio and build, test and install the new BFO.  We also install the chassis in the case and finish up most of the decal placement.

The BFO design was taken from http://www.flashwebhost.com/circuit/bfoceramic.php.  I used power from pin 4 of the IF amplifier.

The next and final episode will show how we make the reproduction knobs and I will give you a final overview of the completed project.

20 07, 2015

Hallicrafters S-38B restoration – Part 4

By | July 20th, 2015|Blog, Halicrafters, Projects|0 Comments

In episode 4 of our Hallicrafters S-38B restoration, we finish the electronic maintenance.  I show how we replaced any out of tolerance resistors and caps.

We also rewire the power cord to make sure it gets plugged in with the the hot side switched.

The speaker is repaired and we turn it on for the first time.


7 07, 2015

Hallicrafters S-38B Restoration – Part 3

By | July 7th, 2015|Blog, Halicrafters, Projects|0 Comments

In part 3 of our Hallicrafters S-38B restoration, we strip the chassis of it’s components and media blast it.  Then we proceed to paint it with Rust-Oleum Stainless Steel appliance epoxy.

After that we start to remount the components onto the chassis.

Next episode we will work on the IF cans and start to recap the chassis.

3 05, 2015

Pic-A-Star Project Build – Part 3

By | May 3rd, 2015|Blog, Projects|0 Comments

In episode 3 of our Pic-A-Star Build, we install the components for the RS232 interface and start installing the components for the DSP and CODEC section.

I find that I made a mistake and installed a 10K thermistor instead of a 10K resistor in the audio amp section, so first I remove that and replace it with the correct component.

I have found that I prefer the 0805 component size over the 1206 or 0603 size.  The 1206 is a little big and doesn’t give you as much wiggle room as the 0805 and the 0603 are just a little small for my tastes.  Call it the Goldilocks syndrome or something, but next time I order, I know what I am going to try to spec.

On the Combo P1 boards, in the DSP section there is a capacitor that isn’t marked real well,  it is C199, I point that out in the video.  I also discover that I need to pay attention to the soldering tabs.  When you put the components on, make sure the long part of the tabs are a crossed from each other.  The space is tight, so sometimes the markings are twisted around and if you are not careful, you can mount them in the wrong direction.

The voltage check in the final section checked out correctly, so next step will be to burn the EPROM with gmon.hex and mount it along with the DSP chip and the CODEC chip.  I am waiting for the CODEC chip, since I had to order it from overseas.  So it may be a week or two before we move on.  In the meantime, I will do a video about burning the EPROM.

28 04, 2015

L/C Meter IIB Build

By | April 28th, 2015|Blog, Projects|0 Comments

I just completed a build of a L/C Meter Kit made by Almost All Digital Electronics.  I have included a video of the build to show how easy it was.  Sorry for the length, I tried something new.  I thought I would tape the whole thing and then edit it.  I won’t make that mistake again, it took too long to edit and I still ended up with a long video.

The build was easy as I said and the kit is really high quality.  I plan on using it to test the inductors for the Pic-A-Star project and my son Brad KD0JCP is finishing up a Genesis G59 and then he will be building the matching GPA10 power amp.  We will use it to check those inductors also.

The IIB measures inductors from .001 uHy to 100 mHy and capacitors from .010 pF to 1 uFD.  It does not check polarized caps.  That range covers most needs and it boasts an Accuracy of 1%.

Take a look at Neil Heckt’s page at www.aade.com.  Tell him KB0ASQ sent you.

25 04, 2015

Pic-A-Star Project Build – Part 2

By | April 25th, 2015|Blog, New Products, Projects|0 Comments

In Part 2 of our Pic-A-Star build, we assemble the “Buzzer” tool and install the components of the AF audio amp.

Since it is my first real experience with soldering a large amount of SMD parts, I have to take it slow and perfect my soldering skills with these types of components.

After some practice I am able to get both of the tasks completed with only a few diodes and transistors being sacrificed.

The next episode of our project build will cover the RS232 installation and some DSP building.

21 04, 2015

Power Management Unit Build – Part 5

By | April 21st, 2015|Blog, New Products, Projects|0 Comments

Part 5 of our Power Management Unit Build will cover the final physical construction and some information on the sketch we did for the Arduino.

I show you how I wired up the front panel LEDs, Buttons and the project board.  I used the following sources from the internet to determine how to wire up the controls and write the sketch:

  1. http://www.arduino.cc/en/Tutorial/Blink?from=Tutorial.BlinkingLED  // Turn the LED on and off.
  2. http://www.arduino.cc/en/Tutorial/Button  // Monitor the momentary push buttons.
  3. http://www.arduino.cc/en/Tutorial/LiquidCrystal // Display information on the LCD.
  4. http://startingelectronics.org/articles/arduino/measuring-voltage-with-arduino/ // Calculate the voltage and convert it to use on the Arduino.
  5. http://openenergymonitor.org/emon/buildingblocks/how-to-build-an-arduino-energy-monitor-measuring-current-only  // Monitor current with a YHDC SCT-013-000 sensor.
  6. http://www.electronicecircuits.com/electronic-circuits/7805-5v-1a-regulated-power-supply-with-overvoltage-protection-circuit // 5v 7805 1A Regulated Circuit.
  7. http://blog.startingelectronics.com/arduino-web-server-tutorial/ // Webserver Tutorial.

I would like to thank those authors for sharing the information.  I took bits and pieces from them to build the project.

In my next post about the project, I will share the Arduino sketch and provide a wiring diagram.

I am going to leave this project as is for now, but at a later date I want to add the ability to use DHCP for the webserver and then be able to set a static IP address.  I also need to add a security/login method to the project.

14 04, 2015

Power Management Unit Build – Part 4

By | April 14th, 2015|Blog, Projects|0 Comments

In part 4 of our Power Management Unit Build, we start to wire things up.  There are essentially two separate sections we have to wire.

First we wire the power to the power supply and then to the relays, fuses and power poles.  I have a fuse that protects the hot side of the power supply and then each port has a 10 amp fuse installed on the hot side to protect the devices attached to the unit.

I show how I don’t trust the crimp connectors, so I remove the plastic insulators from them and crimp, solder and finally use heat shrink tubing to protect the connectors.  I also use WAGO LEVER-NUTS for the first time.  I am really happy with how they work and plan on using them again.

To wire up the connections for the controls and the Arduino, I use jumper wires from Pololu and some of our own connectors from Flatwater Trading Post.

The 5v power supply is also hooked up.  I have a heatsink on the LM9805 since it runs so hot.

At the end of this episode we have the Unit running like it was on the breadboard.  So we have to finish the wiring of the momentary switches, port LED’s and the current indicator circuit.

We will do that in Part 5 of the series.