BACKGROUND

In a world of 'order online' for the latest and greatest gadgets and gizmos, I decided to take a step back in time and attempt my first radio restoration. The radio chosen for my very first restoration project, was a random Heathkit HW-101 (hot water 101, as commonly referred to) that turned out to be actually in dire need of repair.With my background in electronics for several decades, the project was still a challenge, but sure worth the effort. Would like to make a recommendation to any amateur radio operator with a strong troubleshooting background, to first research and then decide on a restoration project of their choice. I will caution though (with older tube equipment and associated power supplies) there are several safety items to be aware of including: High voltage safety, incorrectly installed components, non-approved modifications and many others when attempting a project such as this. I cannot stress the safety factor enough. One needs to be well trained and be very familiar with electronics and electricity. Working on or repairing this or similar equipment is at your own risk.

As an aid, there are several online forums and many radio operators more than willing to help answer any questions in assisting with your journey to completion. It amazed me just how large of a community of hams that restore radios. This can be a hobby just in itself. After a lot of fun, hard-work and yes, sometimes even frustration; the HW-101's receiver and transmitter was fully aligned and calibrated. Basic electronic test equipment was used. A full range multimeter, RF probe and frequency counter was utilized among other equipment. An oscilloscope is highly encouraged. A good quality RF dummy load is essential for transmitter alignments. Ultimately, made several DX contacts and ragchews. It turned out to be a winner. There is something to be said for these older rigs. It gives a sense of nostalgia and pride knowing that one more radio is back on the air, instead of on the scrap heap.

HW-101 RESTORATION PROJECT - YEAR 2025

Old HW-101 (dating back to circa 1975) in desperate need of restoration. Also, included are photos of an HP-23C power supply and Astatic D-104 microphone repairs.

• Replaced all electrolytic, film and mylar capacitors.
  
• Installed new 6146A final tubes and several other tubes in the modulator, RF driver, I.F. and bandpass circuits, as appropriate, also with new replacements.
  
• Swapped out carrier null potentiometer, installed Schottky diodes and replaced several tubes.
  
• Overhauled VFO and applied service bulletin upgrades, as appropriate.
  
• Upgraded HP-23C power supply and D-104 high impedance element.
  

PROCESS


This is the HW-101 with the tubes and VFO removed. Ready for deep cleaning.



Old components that need removal from an HP23C power supply



Gutted out parts and need to see what I can salvage to use.



D-104 needed a new element and rewiring.



Radio has been cleaned and new components, as necessary, are being installed.



Testing and replacing, as necessary, vacuum tubes and various components in power supply and radio. Ordered a lot of parts, but making progress.



Installed different SSB filter and missing CW filter (shown in green circle).



Conducted initial turn-on, and went through receiver and transmitter alignments. Checked frequency accuracy, spurious emissions, nulled carrier and finals neutralized.



Installed HP-23C circuit board / upgrade kit. Existing power transformer and choke tested fine.



Transmitter power output exceeded my expectations. Wonderful wattage output. Tested with a dummy load.



Final assembly and on-air contacts. Repainted covers in sage green, for a nostalgic appeal.


Final thoughts: Was certainly an interesting process of restoration. Many challenges along the way, but ultimately, a fun learning experience. Wishing you all the best in your future restoration projects.

Dave, AC3HT , ECARS 3620

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