UPDATE: JANUARY 22, 2017
Hallicrafters S-40A
Restoration of a 1946 Hallicrafters S-40A General Coverage Receiver
While the National HRO-500 awaits parts, we have begun the restoration of a 1946 Hallicrafters S-40A.
Hallicrafters S-40A
That's what they look like when fully restored. This one was done by Jeff Miller
***
Our journey begins with a not-too-bad specimen, acquired in 2005 off eBay for $30.
1946 Hallicrafter S40-A: Faceplate & Cabinet
After a thorough cleaning, the faceplate and cabinet emerge intact. No dents.
***
Chassis: Top and Bottom
Chassis cleaned up after a thorough cleaning with dishwater liquid, followed by Brasso and cotton rags.
Beneath the chassis lie the original components, including paper capacitors and blown power resistors.
***
\
Band spread Flywheel & Transformer Case
The tuning capacitor and pulley mechanism are removed from the chassis and cleaned. While being spun by a cordless drill, the flywheel is slathered with Brasso and buffed with cotton rags.
The pulpy mechanism is reinstalled and lubed with Mobil 1 and white lithium grease. The top of the power transformer is then removed, sanded, primed and painted.
Restoration forums say the rust spots on the chassis can be removed through application of Naval Jelly with Q-tips.
No interest in doing that here, for this not a museum-grade restoration. It's a W1ZY clean-up.
***
Arrival of Components from Just Radios®
Elation greets the arrival of capacitors and power resistors
***
Enlarging the S40-A Schematic
After being downloaded from the internet, a high-resolution S40-A schematic is blown-up and printed on 8.5" x 11" sheets of photographic paper, which are then trimmed and taped together.
The resulting mosaic--measuring 3 feet by 2.5 feet--is then populated with useful information, such as resistor wattages, power busses and cathode return circuits.
***
Schematic Hung Over Workbench
With its hanging over the work bench, the schematic acts as a road map when tracing point-to-point wiring in the chassis.
Prior to that, a magnifying glass was needed to read a smaller schematic.
***
Re-capping with the Foil-Side of Capacitors Towards Ground
The rewarding work of re-capping the radio begins. Care is taken to connect the "foil-side" of capacitors to the part of the circuit closest to ground potential. This reduces hum.
To check a capacitor, hold it between your fingers while touching each lead with an oscilloscope probe. Your fingers act like an antenna. Whichever lead shows MOST hum on the scope is the "foil side".
***
Rebuilding the Power Supply
Although the can capacitor remains in the chassis, it is disconnected from the circuit. It is replaced by fresh electrolytic capacitors which are mounted along a terminal strip.
At first, high-wattage resistors are wired to the terminal strip to check voltages. But then they are then moved to the rear of the chassis, and stacked like rifles in the back window of a F-150 between two terminal strips.
This protects other components from the heat they generate, and eases their measurement and eventual replacement in the future.
Low-wattage resistors connected in series & shrink-wrapped allow the testing of voltages while waiting for the arrival of a high-wattage resistor.
The original tube rectifier (80) was initially supplanted by silicon diodes; its filaments were left wired for visual effect.
However, the rectifier tube was re-introduced after it was discovered that the higher efficiency of the silicon diodes registered a 10% increase in plate and screen voltages.
***
New "Fender" Toggles & Switchcraft 1/4" Headphone Jack
S40-A toggle switches are replaced with new "Fender" switches ($4/ea.).
The new toggle switches and headphone jack enhance the pleasure derived from operating the antiquated shortwave receiver.
These new items will spruce up the appearance of the restored radio since they are the only controls exposed on the front panel. All others being concealed by Hallicrafters "cupcake" knobs.
***
#44 Pilot Lamps Arrive
6-Volt pilot lamps are installed upon their arrival from Antique Electronic Supply (10 for $3).
The dry and cracked powering wires are ensconced in shrink-wrap tubing. Done.
***
Tuning Pulleys Restrung
New dial cord is restrung upon its arrival from Antique Radio Supply (8' for $8).
This completes restoration of the tuning mechanism. Done.
***
Just a pretty picture taken by a proud father.
***
JANUARY 32, 2017
The Aesthetics of the Front Panel & Cabinet
After getting the final screen-dropping resistor in place, and checking the voltages throughout the circuit, we put the chassis aside to work on refinishing the front panel and cabinet. At the top of this list is obtaining a perfect color-match between the old and new paint. I thought this might be impossible since the Hallicrafters S40-A has a unique color, which does not appear to be black. It appears to be slightly lighter than black, with perhaps an olive or green or blue tint to it. But this does not turn out to be correct. What happens is that when flat black paint is applied, the metal does something that causes the color to match the original color--as we shall shortly see.
The Process
First I turned my attention to the front panel. I cleaned it with "Super Clean", available at Home Depot, WalMart and auto stores. This really cleans the chassis and cabinet of old radios.
After cleaning the front panel, I then made a number of measurements depicting the placement of various labels on the panel. A lot of photographs were taken during this stage, along with measurements and copious notes taken down on paper. This produces a record for the precise placement of decals after the panel has been painted.
I then sanded and cleaned the front panel with Spray Clean, and then rinsed it. And then cleaned it again with Acetone, after which I hit it with a tack cloth to get every, last anal-compulsive speck of anything off it. Nervously I began shaking a can of Rustoleum Gray Auto Primer. With the front panel leaning against the bottom of one of the re-cycle containers, previously used to restore the SB-221 last Spring, I rolled my office chair up to the victim. I lowered it and began to spray the panel--hoping I was not making a mistake. When I was through, I placed it kitty-cornered over the edge of the table and the operating position to let it dry over the electric (oil) heater which I rolled beneath it. The paint can says it takes about 10 minutes to dry. I am nervous All the patina coveted by The Collectors is gone. Jittery, I go into the kitchen to get some coffee. When I return, I almost drop the cup when I see what I had done...
Dayem! It looks great! I might not even paint the black on it. I take a swig of coffee admiring the thing, and set the cup down. Determined to experiment, I flip the front panel and paint the backside with the the Kyron flat black--just to see what it looks like. Just to see if it is too black. I put the panel back kitty-cornered over the edge of the operating position and up-loaded some of these photos to the QRZ.com page. As you know, that took several hours. Just kidding. A few minutes later, I check out the panel. Dayem again! It looks even better than the gray primer! I shake the can of flat black Krylon, which I had left on the radiator to warm up, and start spraying the front panel. As McDonald's says, "I'm Luvin' It!" After three coats, the front panel pretty closely color-matched the original paint--as seen in the photograph below.
Very nice match. So we are now prepping the cabinet for the same treatment. Start with the perforated top. Remember to spray the paint in at angles at the end in order to get the sides of the perforations, where rust is often times lurks.
The perforated top comes out perfect. Three coats. I then sand and clean the cabinet, getting it ready for the primer.
After the auto gray primer and two coats of the Krylon flat black, this is what we get. Yes.
Done.
Now we perform a partial re-assembly sans chassis.
The types of paint I used were Rustoleum Automobile Primer (gray), followed by Krylon "Colormaster" Flat Black. That's what you see applied in these photographs. After putting the decals on, I used Krylon Clear Coat (gloss). This brought the color down to true black, which was a slight disappointment because I liked the hue of the flat black. It matched the original Hallicrafters finish perfectly. So if I did it again, I might try using Krylon Clear Coat (matte), if it exists. Perhaps that would not cause the same darkening of the base coat color. You will see what I am talking about a bit further down in the photographs depicting the front panel after application of the decals. Until then, check out the nice results from using the flat black.
We are now ready to put the decals on the front panel. Stay tuned....
Application of the Decals
The decals were ordered from Antique Electronics Supply ($15). Although the restoration forums all reported that one needed to use a watercolor paintbrush to position the decals after they had been slipped off their paper backings, I found use of my index finger more convenient. As seen in the photographs below, the decals worked wonderfully. At first you could see the trim off to the sides of the decal lettering. But this totally disappeared after application of clear coat to seal and protect the decals. As previously indicated, application of the clear coat also darkened the hue to the base coat, bringing it to true black. No worries, though. The results were quite acceptable--especially when compared to the original condition of the receiver cabinet.
Before & After
Comparison between the original S40-A front panel and after application of decals and one coat of clear coat.
***
A General Overview
One coat of clear coat is seen depicted in these photographs of the front panel, which appears to provide sufficient protection to the decals without raising the gloss of the front panel's finish.
In this restoration, however, several additional layers of clear coat were applied to raise the gloss of the front panel, as seen in subsequent photographs.
Do not be afraid to cut the decals as close as possible to eliminate trim area. Once they are coaxed from their paper backing, they can be positioned with a watercolor brush or an index finger with ease.
After getting the decal positioned properly, a dab with a Kleenex removes excess water. Pressing down on the Kleenex also secures the decal to the front panel surface.
***
Detail of Decals
When first applied, the film of the decals is clearly visible. However, it disappears after application of one coat of clear coat.
A slight is evident in the "the" of the Hallicrafter decal, which was subsequently touched-up with a watercolor brush dabbed with a smidgen of flat black paint. Additional layers of clear coat followed.
On the right, a small defect can be seen int he paint, which was sanded down and re-painted before adding more layers of clear coat.
***
Clear Coat: Before & After
For anyone about to do this restore, the photograph on the left shows the luster of the front panel after one coat of clear coat. On the right we see the luster after 7 additional coats.
***
Details of Decals: S40-A & The Hallicrafters Co.
Seen above are the finished states for the S40-A and Hallicrafters decals.
We can see the removal of the blemish from the panel finish previously seen below the S40-A decal, as well as the removal of the film artifact from the "the" of the Hallicrafters decal.
***
UPDATE: JANUARY 22, 2017
Hallicrafters S-40A
Restoration of a 1946 Hallicrafters S-40A General Coverage Receiver
While the National HRO-500 awaits parts, we have begun the restoration of a 1946 Hallicrafters S-40A.
Hallicrafters S-40A
That's what they look like when fully restored. This one was done by Jeff Miller
***
Our journey begins with a not-too-bad specimen, acquired in 2005 off eBay for $30.
1946 Hallicrafter S40-A: Faceplate & Cabinet
After a thorough cleaning, the faceplate and cabinet emerge intact. No dents.
***
Chassis: Top and Bottom
Chassis cleaned up after a thorough cleaning with dishwater liquid, followed by Brasso and cotton rags.
Beneath the chassis lie the original components, including paper capacitors and blown power resistors.
***
\
Band spread Flywheel & Transformer Case
The tuning capacitor and pulley mechanism are removed from the chassis and cleaned. While being spun by a cordless drill, the flywheel is slathered with Brasso and buffed with cotton rags.
The pulpy mechanism is reinstalled and lubed with Mobil 1 and white lithium grease. The top of the power transformer is then removed, sanded, primed and painted.
Restoration forums say the rust spots on the chassis can be removed through application of Naval Jelly with Q-tips.
No interest in doing that here, for this not a museum-grade restoration. It's a W1ZY clean-up.
***
Arrival of Components from Just Radios®
Elation greets the arrival of capacitors and power resistors
***
Enlarging the S40-A Schematic
After being downloaded from the internet, a high-resolution S40-A schematic is blown-up and printed on 8.5" x 11" sheets of photographic paper, which are then trimmed and taped together.
The resulting mosaic--measuring 3 feet by 2.5 feet--is then populated with useful information, such as resistor wattages, power busses and cathode return circuits.
***
Schematic Hung Over Workbench
With its hanging over the work bench, the schematic acts as a road map when tracing point-to-point wiring in the chassis.
Prior to that, a magnifying glass was needed to read a smaller schematic.
***
Re-capping with the Foil-Side of Capacitors Towards Ground
The rewarding work of re-capping the radio begins. Care is taken to connect the "foil-side" of capacitors to the part of the circuit closest to ground potential. This reduces hum.
To check a capacitor, hold it between your fingers while touching each lead with an oscilloscope probe. Your fingers act like an antenna. Whichever lead shows MOST hum on the scope is the "foil side".
***
Rebuilding the Power Supply
Although the can capacitor remains in the chassis, it is disconnected from the circuit. It is replaced by fresh electrolytic capacitors which are mounted along a terminal strip.
At first, high-wattage resistors are wired to the terminal strip to check voltages. But then they are then moved to the rear of the chassis, and stacked like rifles in the back window of a F-150 between two terminal strips.
This protects other components from the heat they generate, and eases their measurement and eventual replacement in the future.
Low-wattage resistors connected in series & shrink-wrapped allow the testing of voltages while waiting for the arrival of a high-wattage resistor.
The original tube rectifier (80) was initially supplanted by silicon diodes; its filaments were left wired for visual effect.
However, the rectifier tube was re-introduced after it was discovered that the higher efficiency of the silicon diodes registered a 10% increase in plate and screen voltages.
***
New "Fender" Toggles & Switchcraft 1/4" Headphone Jack
S40-A toggle switches are replaced with new "Fender" switches ($4/ea.).
The new toggle switches and headphone jack enhance the pleasure derived from operating the antiquated shortwave receiver.
These new items will spruce up the appearance of the restored radio since they are the only controls exposed on the front panel. All others being concealed by Hallicrafters "cupcake" knobs.
***
#44 Pilot Lamps Arrive
6-Volt pilot lamps are installed upon their arrival from Antique Electronic Supply (10 for $3).
The dry and cracked powering wires are ensconced in shrink-wrap tubing. Done.
***
Tuning Pulleys Restrung
New dial cord is restrung upon its arrival from Antique Radio Supply (8' for $8).
This completes restoration of the tuning mechanism. Done.
***
Just a pretty picture taken by a proud father.
***
JANUARY 32, 2017
The Aesthetics of the Front Panel & Cabinet
After getting the final screen-dropping resistor in place, and checking the voltages throughout the circuit, we put the chassis aside to work on refinishing the front panel and cabinet. At the top of this list is obtaining a perfect color-match between the old and new paint. I thought this might be impossible since the Hallicrafters S40-A has a unique color, which does not appear to be black. It appears to be slightly lighter than black, with perhaps an olive or green or blue tint to it. But this does not turn out to be correct. What happens is that when flat black paint is applied, the metal does something that causes the color to match the original color--as we shall shortly see.
The Process
First I turned my attention to the front panel. I cleaned it with "Super Clean", available at Home Depot, WalMart and auto stores. This really cleans the chassis and cabinet of old radios.
After cleaning the front panel, I then made a number of measurements depicting the placement of various labels on the panel. A lot of photographs were taken during this stage, along with measurements and copious notes taken down on paper. This produces a record for the precise placement of decals after the panel has been painted.
I then sanded and cleaned the front panel with Spray Clean, and then rinsed it. And then cleaned it again with Acetone, after which I hit it with a tack cloth to get every, last anal-compulsive speck of anything off it. Nervously I began shaking a can of Rustoleum Gray Auto Primer. With the front panel leaning against the bottom of one of the re-cycle containers, previously used to restore the SB-221 last Spring, I rolled my office chair up to the victim. I lowered it and began to spray the panel--hoping I was not making a mistake. When I was through, I placed it kitty-cornered over the edge of the table and the operating position to let it dry over the electric (oil) heater which I rolled beneath it. The paint can says it takes about 10 minutes to dry. I am nervous All the patina coveted by The Collectors is gone. Jittery, I go into the kitchen to get some coffee. When I return, I almost drop the cup when I see what I had done...
Dayem! It looks great! I might not even paint the black on it. I take a swig of coffee admiring the thing, and set the cup down. Determined to experiment, I flip the front panel and paint the backside with the the Kyron flat black--just to see what it looks like. Just to see if it is too black. I put the panel back kitty-cornered over the edge of the operating position and up-loaded some of these photos to the QRZ.com page. As you know, that took several hours. Just kidding. A few minutes later, I check out the panel. Dayem again! It looks even better than the gray primer! I shake the can of flat black Krylon, which I had left on the radiator to warm up, and start spraying the front panel. As McDonald's says, "I'm Luvin' It!" After three coats, the front panel pretty closely color-matched the original paint--as seen in the photograph below.
Very nice match. So we are now prepping the cabinet for the same treatment. Start with the perforated top. Remember to spray the paint in at angles at the end in order to get the sides of the perforations, where rust is often times lurks.
The perforated top comes out perfect. Three coats. I then sand and clean the cabinet, getting it ready for the primer.
After the auto gray primer and two coats of the Krylon flat black, this is what we get. Yes.
Done.
Now we perform a partial re-assembly sans chassis.
The types of paint I used were Rustoleum Automobile Primer (gray), followed by Krylon "Colormaster" Flat Black. That's what you see applied in these photographs. After putting the decals on, I used Krylon Clear Coat (gloss). This brought the color down to true black, which was a slight disappointment because I liked the hue of the flat black. It matched the original Hallicrafters finish perfectly. So if I did it again, I might try using Krylon Clear Coat (matte), if it exists. Perhaps that would not cause the same darkening of the base coat color. You will see what I am talking about a bit further down in the photographs depicting the front panel after application of the decals. Until then, check out the nice results from using the flat black.
We are now ready to put the decals on the front panel. Stay tuned....
Application of the Decals
The decals were ordered from Antique Electronics Supply ($15). Although the restoration forums all reported that one needed to use a watercolor paintbrush to position the decals after they had been slipped off their paper backings, I found use of my index finger more convenient. As seen in the photographs below, the decals worked wonderfully. At first you could see the trim off to the sides of the decal lettering. But this totally disappeared after application of clear coat to seal and protect the decals. As previously indicated, application of the clear coat also darkened the hue to the base coat, bringing it to true black. No worries, though. The results were quite acceptable--especially when compared to the original condition of the receiver cabinet.
Before & After
Comparison between the original S40-A front panel and after application of decals and one coat of clear coat.
***
A General Overview
One coat of clear coat is seen depicted in these photographs of the front panel, which appears to provide sufficient protection to the decals without raising the gloss of the front panel's finish.
In this restoration, however, several additional layers of clear coat were applied to raise the gloss of the front panel, as seen in subsequent photographs.
Do not be afraid to cut the decals as close as possible to eliminate trim area. Once they are coaxed from their paper backing, they can be positioned with a watercolor brush or an index finger with ease.
After getting the decal positioned properly, a dab with a Kleenex removes excess water. Pressing down on the Kleenex also secures the decal to the front panel surface.
***
Detail of Decals
When first applied, the film of the decals is clearly visible. However, it disappears after application of one coat of clear coat.
A slight is evident in the "the" of the Hallicrafter decal, which was subsequently touched-up with a watercolor brush dabbed with a smidgen of flat black paint. Additional layers of clear coat followed.
On the right, a small defect can be seen int he paint, which was sanded down and re-painted before adding more layers of clear coat.
***
Clear Coat: Before & After
For anyone about to do this restore, the photograph on the left shows the luster of the front panel after one coat of clear coat. On the right we see the luster after 7 additional coats.
***
Details of Decals: S40-A & The Hallicrafters Co.
Seen above are the finished states for the S40-A and Hallicrafters decals.
We can see the removal of the blemish from the panel finish previously seen below the S40-A decal, as well as the removal of the film artifact from the "the" of the Hallicrafters decal.
***
High-gloss Detail of Front Panel
Above we see the result of 8 layers of clear coat (gloss) applied over the flat black base coat.
***
Preparation of the Dial Plate
Blue painters tape protects the dial plate glass from paint. The plate assembly has been sanded with 600-grit sandpaper.
White-Out has been rubbed into the band position numbers in an effort to reclaim them after painting.
The idea being to pick the White-Out out of the numbers and re-apply White-Out.
***
Dial Plate: Before & After
Here we see the dial plate after priming, painting and clear coating.
***
Final Assembly
Initial photography of restored S40-A.
The receiver will be set aside in the warm house for several days to allow the clear coat to harden.
***
Coming Up Next
Aligning the receiver with a sweep generator...
High-gloss Detail of Front Panel
Above we see the result of 8 layers of clear coat (gloss) applied over the flat black base coat.
***
Preparation of the Dial Plate
Blue painters tape protects the dial plate glass from paint. The plate assembly has been sanded with 600-grit sandpaper.
White-Out has been rubbed into the band position numbers in an effort to reclaim them after painting.
The idea being to pick the White-Out out of the numbers and re-apply White-Out.
***
Dial Plate: Before & After
Here we see the dial plate after priming, painting and clear coating.
***
Final Assembly
Initial photography of restored S40-A.
The receiver will be set aside in the warm house for several days to allow the clear coat to harden.
***
Coming Up Next
Aligning the receiver with a sweep generator...
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