|The Truetone Series 7J is a large 7-tube AC Superhet
circuit radio that receives the broadcast band and one short wave band.
Truetone was a brand sold by Western Auto Supply. This particular radio
was made by Wells-Gardner (W.G. 24).
The radio had seen some servicing in the past. There was a radio shop label still on the cabinet. Three wax-paper capacitors had been replaced, the power cord replaced, and some tubes likely had been replaced. Since the radio was still largely original, I decided to try to get it working yet maintain the original top and bottom chassis appearance and to reverse any previous repairs to the extent possible.
The schematic for the radio can be found on Nostalgia Air. Any part numbers will refer to numbers on that schematic.
My antique radio restoration logs
This radio was purchased at the 2014 CC-AWA Antique Radio Conference and Flea Market in Charlotte, NC. Being made by Well-Gardner, the build quality is very high. The working status was not stated by the seller. The cabinet finish, grille cloth, and knobs were original and in good condition. All tubes and tube shields were in place. The often missing chassis retainers (L-shaped and threaded) were in place, as were the chassis cushions. There were no shipping bolts present.
The radio had seen a minimal amount of repair in the past, and all repairs were far in the past, judging from the vintage of the components used. This was a well loved radio that someone paid a lot to have repaired.
Three wax-paper capacitors had been replaced. In this radio this is a difficult task, since all tubular wax-paper capacitors are secured by clamps (fortunately held by screws rather than rivets).
The original filter capacitors were still in place.
It is likely that some or perhaps all tubes had been replaced. Three were branded Wizard, three branded RCA, and one branded Philco. The Wizards may have been original.
All of the original resistors were still in place.
The line cord had been replaced.
My usual restoration procedure is to first make a complete survey of the condition of all components. The survey results guide my restoration strategy. If major and unique components are defective or missing and cannot be restored or replaced, I may elect to sell the radio rather than restore it. I always assume that all paper and electrolytic capacitors are leaky and thus should be replaced (I always "restuff" the original containers if possible). Any mica capacitors are assumed OK until testing proves otherwise. I never apply power to an unrestored radio, even through a variac or "dim bulb" tester.
Seven resistors were out of tolerance (more than +/-20%). All were old style dogbone type resistors of various wattages.
The speaker cone, field coil, and output transformer were OK.
The power transformer was OK. The high voltage was balanced across the center tap with 20 volts applied through a variac. With full power applied (no tubes present), the wattage consumed was less than 10 watts. A transformer with shorted turns will draw excessive power and will heat up. I use a real analog watt meter for these tests.
One pilot lamp socket was missing (the power lead was still in place).
The wire wound resistor R13 was fortunately good and in tolerance.
All RF coils and transformers were OK.
The IF transformers were OK.
All tubes were good.
The chassis cushion washers still OK.
The tuning capacitor mounting grommets had hardened and shrunk, allowing the capacitor to move around.
All wiring was cloth covered and was OK.
All tube shields were present.
The pilot lamp was burned out
The chassis was very dirty. All tubes and shields were removed and dust was removed using an air compressor. Before starting repairs, I took photos of the chassis bottom so that routing of wiring and component placement could be restored. Lead dress is often critical in radios. The tuning capacitor was removed for cleaning and for replacement of the mounting grommets. The two can type filter capacitors were removed for restuffing and chassis access for cleaning.
I then removed all of the non-original capacitors, documenting their locations and connections. When I replace a component, I always remove the original part completely from a terminal. Other components such as mica capacitors and in-tolerance resistors connected at the terminal are protected from heat using old medical clamps (hemostats). Excess solder is then removed using a solder sucker in order to expose terminal holes for reattachment of the rebuilt or replaced component.
The top and sides of the chassis were cleaned with GoJo hand cleaner and 00 steel wool. Since this process may leave metal residue, I then went over the chassis with a vacuum cleaner followed up by a small magnet and masking tape. The tuning capacitor trimmer hardware and mica insulators were removed to prevent damage during cleaning. I noted the original positions of the trimmer adjustments so that they could be returned to the original positions. I do this by counting the number of half-turns of the adjustment screw to fully tight. The tuning capacitor was cleaned using in my old Heathkit ultrasonic cleaner using dilute ammonia, followed by soap, water, and old toothbrushes. After drying, the bearing surfaces were lubed with automotive distributor cam lubricant. The tuning capacitor grommets were replaced by GLg-Tuner grommets from Renovated Radio, thick side up. These worked OK, but the center hole was slightly large and allowed some movement of the capacitor. These grommets were also slightly too short, so flat washers were added between the capacitor body and the grommets.
The original wet type filter capacitors were still in place. One (C25, 14mfd/400 volts) was insulated from the chassis. The other (C26, 18mfd/300 volts) was not insulated from the chassis. I was able to remove C25 easily using a large socket wrench. But the threads on C26 were stripped and I was NOT able to remove the part. I was forced to cut off the body and then grind off the remainder of the capacitor. I found a similar part in my junk box to replace it. Both capacitors were restuffed with suitable new electrolytics. I used 15mfd/450 volts for C25, and 22mfd/450 volts for C26.
Here is my restuffing process for these wet type electrolytics:
All the wax-paper capacitors in the radio were marked with a part number starting with 46X, and also marked with the value and voltage rating (normal and peak). The capacitors used by Wells-Gardner are unusual in that their voltage ratings are values such as 180, 240, or 360 volts etc. Their construction is also unusual. The capacitor is assembled inside a cardboard tube, the ends of which are crimped. Inside both ends is a metal disc, to which the component leads are soldered. The foil roll is soldered to an extension of each lead on the inside. The tube is filled with wax (and in one case, with tar). These capacitors are difficult to restuff without the repair being visible. There is really no way to "uncrimp" the ends without making a mess. My restuffing process is as follows:
Three original capacitors had been replaced: C6 and C21 (0.1mfd/360 volts) and C9 (.25mfd/240 volts). I collect both branded (Zenith, Philco, etc.) and generic dud capacitors. However I did not have the correct original Wells-Gardner parts in stock. For C6 and C21 I used Wells-Gardner part number S46X98 (.1mfd/180 volts) restuffed using 0.1mfd/630 volts. For C9 I used part number 31077 .25mfd/400 volt restuffed using 0.22mfd/630 volts.
All resistors in the set were old style dogbone types and were all original. Seven resistors were out of tolerance by more than 20%. I maintain stocks of NOS and used dogbone resistors, and buy all I can find that are reasonably priced. I also NEVER throw away a used dogbone resistor, even if out of tolerance. One resistor (R7) was inside the second IF transformer shield can, and thus hidden. I replaced this one with a standard 1/2 watt carbon resistor. For R2 and R8 I found NOS dogbone resistors in my stock that were in tolerance. For the remainder, I found replacements that were the correct size and in tolerance for the needed values. These were repainted to the correct values using hobby enamel paint.
The missing pilot lamp socket was replaced by a similar part. The original socket was screw based. The only suitable part I had in stock was bayonet based. The extant power lead was reused. The missing shipping bolts were replaced by 4" 1/4-20 carriage bolts. I think they should have been 5/16" diameter. The bolts were shortened by about 1/4" to prevent them protruding from the bottom of the cabinet. I have never seen original shipping bolts and nuts, since these are normally removed and discarded by the original owners.
The cabinet was vacuumed and then cleaned using GoJo (the white type, not pumice) hand cleaner and 00 steel wool. The grille cloth was simply vacuumed.
Once the radio was reassembled and the tubes installed, power was brought up slowly using a variac. A DVM monitored the B+. The radio came alive immediately and worked. It was then aligned.
Most of my restoration objectives were met, but not all. There was no intention of restoring the set to factory new appearance! My objective is usually to reverse any prior servicing and make the radio appear to have never been repaired. I do not go so far as to artificially "age" solder joints, as do some collectors! Here are some of my "misses":