Doug Moore, KB9TMY
Editor's Note: Rig pictured is not actual rig restored
|This little gem was given to me by an ex-Hallicrafters employee, who extracted it from his basement where it had been for the last 25 years. Bringing it up on a variac produced no smoke, but alas, no sound either. There was some noise when switching bands, so it seemed like the power supply and audio system was working. The main dial cord was sticking and slipping, and the band indicator gizmo didn't work at all. On the plus side, there was no loud hum, so perhaps the electrolytics were still good. Opening the back, I was greeted with the potent odor of cadmium oxide. Removing the chassis was fairly simple, two hex nuts holding the panel and three screws in the bottom holding the chassis. The internal antenna plugged into the tuner section, so could be unplugged with ease.|
After chassis removal, I gave
the unit a preliminary cleaning with an old paintbrush to remove
most of the cadmium oxide. This was followed by a wipedown with a
damp rag and a very light coat of de-ox-it. I tried to be careful
not to ingest or inhale any of the cadmium dust. Next, I took a
look at the underside of the chassis and was greeted by a couple
of handfuls of the dreaded "black beauty" capacitors,
some of which showed signs of leaking oil. Rather than just do a
bulk recap of the entire unit, I thought I'd investigate why the
set didn't play, and possibly show up any drastic problems first.
The bandswitching method on this set is quite unique, resembling the Standard Coil TV tuner of days gone by. (In fact, I'd swear it had some of the same parts.) I quickly discovered that I could get some signal on the AM band by touching the center lug of the three gang variable. I concluded that the oscillator and mixer were working, but the RF amplifier stage was dead. Since the bandswitching turret blocked the converter and RF amplifier tube sockets, I removed the 1U4 tube and plugged in a test adapter. The problem was quickly discovered, zero volts on the 1U4 plate. Naturally, the suspect components were buried under the turret beneath the tube socket. In order to access this area, it was necessary to temporarily remove about three of the snap-in band coils. I found an open resistor, (R102) and while I was in the area, replaced the "black beauties" which would be hidden when I replaced the band coil modules. Snapping these back in and firing up the set, I was rewarded by music from a local AM station.
The next project was to restring the dial cords. There are three cords, two for the main tuning, and one for the bandswitching indicator. To get at the dial cords, you need to remove the glass dial cover, the dial pointer, the metal dial plate, the tuning and volume knobs, and the speaker baffle. The easiest thing to do in the latter case is unsolder the speaker wires and leave the speaker bolted to the baffle. For restringing the cords, I used 45 pound test dacron fishing line. (Gudebrod #518) I had a stringing diagram for the TW-1000, which is almost identical electrically, but somewhat different mechanically. The bandswitch stringing was the same, but the main tuning stringing was different. Since the old cord was still mostly intact, I just made my own drawings of how it was done. After the old cord was removed, I carefully cleaned and lightly lubed all the pulleys and shafts, then re-cleaned the main tuning shaft in the area where the cord wrapped around. (Any lube left here will do more harm than good.) On the cord ends, I used tied loops, then dabbed the knots with Duco cement. An alternate technique is to use small brass eyelets to form the loops. The loop can be easily adjusted to the correct length, and then the eyelet is squeezed with a pair of pliers, and dabbed with cement. Following the stringing, everything was tested with the knobs temporarily back in place, and all worked well. The baffle, dial plate and dial glass were carefully cleaned, using only WATER on the dial markings, then reassembled. The dial pointer was attached prior to the reattachment of the dial glass bezel, and after positioning, was fastened to the cord with another dab of cement. When resoldering the speaker leads, be VERY careful not to touch your new dial cord with the soldering iron!
The next task was to finish cleaning the contacts on the bandswitch, lube the cam on the bandswitch detent, and give the volume control a spritz of cleaner. I replaced capacitor C16, which bypasses the B- to the chassis, with a UL approved part. I then examined the remaining "black beauty" capacitors, with the thought of replacing any that looked suspicious, but finally decided to replace them all. The set was then aligned, and played on the bench for a couple of days. While I was "burning in" the chassis, I cleaned the inside of the wood case, then rubbed down the outside surface with auto upholstery treatment. The guts were then reinstalled. The looks and sound were better than I expected for a 47 year old radio.
Later that same day, my wife saw the radio in the basement and asked what it was. I told her it was Hallicrafters' answer to the Zenith Trans-Oceanic. She said, "You know, that radio is the first one you've had that I'd let you put in the living room." Well, to conclude an already long story, the TW-2000 ended up in the living room and now I can't get it away from my wife. She likes to listen to a station from Italy. Maybe it's time to start her on Morse code, or just ask her if she wants to help me finish the SX-28.
Doug Moore - KB9TMY
This page last updated 31 Mar 2001.