A Hallicrafters Junker at Auction
SX-111 Receiver, R-48 Speaker and HT-37 Transmitter
BY CLAUDE CHAFIN
Never pass an "Auction Today" sign by is the moral of Claude Chafin's story. And never hesitate to look even further than the auction itself, if the opportunity presents itself. (Editor)
Imagine yourself one spring day driving home when you see a sign posting "Auction Today." Curious, you investigate, hoping to find something of interest.
In the spring of 2009, that was what happened to me here in Kansas City in a local suburb. Upon entering the house where the auction was being held, I found what appeared to be some old Amateur radio equipment. Only the chassis were present, no cabinets. Turns out the equipment was a Hallicrafters SX-111 receiver and matching R-48 speaker plus the companion HT-37 transmitter.
They didn't look very handsome without the cabinets, but I bought them anyway for very little money. Before leaving, I snooped around the empty house There in the basement were the manuals for both radios. Then I noticed these large vented metal cabinets. Could I be so lucky? Sure enough, they were the cabinets for the radios. The auctioneer was all too happy to give them to me free of charge. "Everything left in the house," he said, "is going to be cleaned out." Figures 1 and 2 show the SX-111, R-48 and HT-37 after restoration.
Figure 1. The Hallicrafters SX-111 communications receiver and R-48 speaker which were purchased at the "Auction Today."
Once I got them home, I could begin playing with my new "old" toys. Both power cords were in sad shape. To be safe one needs to install new cords of the 3-prong variety.
I started with the receiver -- cleaning the chassis, testing and cleaning all the tubes, cleaning air capacitors and the dial lens, installing the new power cord, and replacing the electrolytics. Some of the mounting screws were missing, but a trip to the hardware store resolved that problem. In the end, I had a great receiver and matching speaker.
Then came the transmitter. It had a relay with a jumble of wires connected to it when I bought it. I thought maybe it was some sort of interconnecting relay for the receiver. Turns out I was right. The contacts were dirty and needed cleaning.
The HT-37 transmitter uses two 6146 tubes in it its final stage. The original tubes tested OK. Figure 3 (see print version) shows the 6146s and the clean chassis.
Figure 2. The repainted Hallicrafters HT-37 transmitter, also purchased at the auction.
It also uses two 20MF/600V electrolytics capacitors. I didn't even bother testing these. Knowing that 50-year-old electrolytic capacitors are not dependable, I changed them out for brand new ones; see Figure 4 (see print version). Why risk a short, open circuit, or who knows what? The power cord was again easy to replace.
The transmitter calls for a high impedance microphone. I already had an old Astatic 10-D I found at a recent Hamfest, perfect for this set up.
The receiver cabinet was in good shape, but the transmitter cabinet had to be repainted. It has an odd shade of gray and today's modern paints don't come anywhere close. Luckily, I found that you can buy an industrial brand that comes pretty close to a match.
Junk No More
Both radios are now functional, as shown in Figure 5. For me, that's part of the fun of finding, restoring, and operating an old piece of equipment that someone had discarded as "Auction Junk."
The 1960 ARRL Ham Radio Manual shows these radios in a new release advertisement in the back of the book. The picture in the ad has the transmitter, receiver, matching speaker and even the Astatic 10-D microphone that I already have matched up with it.
Figure 5. The Hallicrafters SX-111 receiver, HT-37 transmitter and R-48 speaker up and running in my shack -- along with yours truly!
My plan is to have these radios on 20 and 40 meters for Field Day 2010 as a 50th Year Anniversary Special Event Station, N0FMO. A handsome QSL card will be available, if you QSL directly.
ARRL Ham Radio Manual, 1960.
Claude Chafin, an antique radio collector and Ham operator for many years, asks three questions before taking on a repair job: Will his techniques bring it back to normal? Is it too far gone to make the time spent worthwhile? And, does it have a good collectible potential? Affirmative answers mean success, as in this article.