Heathkit XR-1L AM Radio Restoration

My Heathkit XR-1L 

I was the winning bidder of the vintage Heathkit XR-1L AM Radio from an online auction site. I didn't have much competition as Heathkit Ham Radio and High Fidelity Stereo equipment are more widely sought after. My XR-1L was basically intact except that the moulded leather handle was missing. 

There were scuffs and scratches on the leather case due to normal wear and tear. ​

There was a lot of rust and corrosion on the radio chassis, probably caused by chemicals inside dead leaking batteries left in the radio by a previous owner. The battery compartment, shown at the bottom of the picture below, was very rusty. 

My Story

I have a soft spot for Heathkit radios and equipment. As a child I remember my dad being hunched over our dining room table on any given evening, building various pieces of Heathkit equipment. It was my job to inventory all of the discrete parts and to place them neatly in cardboard egg cartons we used as organizers. In addition, I would hand my dad the parts required during the assembly process. At the end of each building session, we would have to carefully move all of the parts to the top of the dresser in my parents bedroom, in order to clear the dining room table for the next meal. The dresser was high enough that it prevented my two young toddler sisters from being able to access it. My parents, two sisters, and I lived in a small three bedroom ranch in a suburb of Cleveland, there was very little extra space for hobbies, other than the dining room table. My dad and I working on Heathkit equipment brings back fond memories, as such, I have become an avid collector of vintage Heathkit equipment. 

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There is a wide variety of completed Heathkit kits available on Amazon. 

Step 1 Initial Testing

In order to establish a baseline of my radio's performance, I decided to power it on to see if it would pick up any stations, prior to restoration. First I removed the chassis from its leather case. Only two screws, circled in red below, hold the chassis in the case. First I had to remove the Tuning and Power/Volume knobs, they just pull off. The chassis pulls straight back and out of the back of the case, once the screws were removed.

As you can see below, the chassis of the Heathkit XR-1L AM Radio is truly a self contained unit. Even the speaker is mounted on standoffs to the component side of the chassis. This radio required 9 Volts, typically supplied by six D Cell batteries. For initial testing purposes, I used a 9 Volt battery, jumpered to the proper connections in the battery compartment to provide power. Initial testing was promising, I immediately heard atmospheric hiss once I turned the volume control to the On position and then set the volume to about midpoint of its range. With some fiddling of the tuning dial, I as able to hear a couple of stations in my regional area that I know have a strong signal. My Heathkit XR-1L was functioning, but its sensitivity left much to be desired. 

Step 2 Electrolytic Capacitor Replacement

As electrolytic capacitors age, their electrolyte dries up causing their electrical capacity to drop and leakage current to increase. It is definitely a good idea to replace 60 year old electrolytic capacitors like the ones in my Heathkit XR-1L!
Electrolytic capacitors should be replaced with one of similar capacitance and equal or above Voltage rating. These type of capacitors are also polarized so make sure you observe the polarity of the capacitor to be replaced and install new the same way.

The speaker must be removed before you can reach the component side of the chassis, where the electrolytic capacitors reside. Four screws, circled in the picture below, hold the speaker to the chassis.

Once the screws have been removed, you must flip the speaker towards the top of the chassis, where the loopstick antenna is attached, so that you can gain access to the wires. You must desolder the yellow and black wires from the speaker terminal in order to remove.

Circled below in red are all of the electrolytic capacitors that need to be replaced. You must remove the Power/Volume control, circled in yellow, from the chassis to gain access to one of the electrolytic capacitors to be replaced. 

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I also took this opportunity to lubricate the shaft of the Power/Volume control as its rotation was quite stiff. I use Labelle 107 Oil as it is safe on plastics and I have it around for my model train hobby. 

Below is a picture of the chassis with the electrolytic capacitors replaced. I have circled the replacement capacitors in red. You'll notice that 60 years of development has led to much smaller capacitors packages. I had to change connection locations as I replaced the original axial package electronic capacitors with radial packaged ones that I keep in stock. 

Once again I took the opportunity to test my Heathkit XR-1L radio after the replacement of electrolytic capacitors. I used alligator clips to temporary connect the speaker to the yellow and black audio transformer leads. In addition, I used alligator leads to connect a 9 Volt battery, used as a temporary power source. Once powered on, I noticed immediately a drastic improvement in the sensitivity of this receiver. I was able to pick up stations accross the entire AM broadcast band! 

Step 3 Disassembly

The chassis of my Heathkit XR-1L radio was pretty rusted and corroded, most likely caused by corrosive chemicals emitted from dead batteries left in the radio many years ago. The only way I could make the chassis presentable again was to sand and then paint it. The first step is to remove as many components as possible from the chassis to make the masking process easier.

I removed the six transistors, they are mounted in sockets. I removed the transistors, one at a time, noting their part number and placement on the chassis.

I removed the side panels, in order to making the paint process easier. Three screws and the Power/Volume control nut must be removed in order to free the right side panel. In addition, you must desolder the solder lug connected to the white wire leading to the battery compartment, then thread the wire through the hole. Once these are removed the right side panel should be free from the chassis. 

You must remove several screws on the left side panel in order to free it from the chassis. 

You must also separate the adjustable bar from the left side panel. The bar has a insulated battery contact that must be removed for paint as well. It is held in place with one screw. Make note of how the insulators are placed on the screw shank. 

The loopstick antenna, circled in red below, must be removed for paint. Plastic mounts on each side hold it to the chassis side plates. I noted the locations were its wire leads are soldered to components on the chassis, then desolder the wires from the antenna. 

I decided to also remove the tuning capacitor from the chassis, first noting its wiring before desoldering wires connecting to it.

Next I removed both interstage and audio transformers from the chassis, first, making note of how they were wired to components on the chassis. I took the picture below after I already removed the audio transformer.

Step 4 Sanding and Polishing

It is important to remove as much rust and corrosion from the chassis and side panels as possible before paint. I used my Dremel tool with either a wire brush or sanding drum to remove the heavier rust deposits.

As a final step, all of the chassis parts were wet sanded with ultra fine 800 grit sandpaper.

As I time saving step, I typically replace rusted hardware (nuts, screws, lock washers) with new. It only adds a couple dollars to the cost of the project. Unfortunately, our local hardware store did not have the same style of slotted screws used to assemble the Heathkit XR-1L chassis. 

Instead, I used my cordless drill, Meguiar's Motorcycle All Metal Polish, and paper towels to shine the screw heads. I would insert the shaft of the screw in the drill's chuck then tighten it down firmly. I would then apply a dab of polish to the paper towel. I would press the paper towel with polish against the screw head while the drill was spinning. I repeated this process with each chassis screw and was amazed at the results. This made the screws look like new!

Meguiar's PLASTX and an old toothbrush work wonders on cleaning up old knobs!

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I use a lot of Meguiar's automotive products when restoring vintage radios. I already have these products on hand for taking care of my cars and motorcycles.

Step 5 Masking and Painting

It is important to remove all wax and grease residue from parts to be painted. Just prior to paint, I wipe down all parts to be painted with Prep-All made by the company Klean-Strip. This clear liquid chemical dries quickly leaving no residue.  

The first item to be painted was the metal speaker frame. I carefully masked off the speaker cone to prevent overspray then applied Prep-All to remove wax and grease residue. Painting the metal speaker frame required two paint sessions, allowing 24 hours of drying time between them. One session to paint the mounting tabs on the front of the speaker and another to paint speaker frame on the back. I used Krylon Shortcuts Chrome spray paint on the speaker frame. It is available at most craft stores. Please see my slideshow below for a pictorial view of the steps. 

On many parts to be painted, I use magnet wire to suspend them. This allows me to paint all surfaces and then let them hang to dry.

I carefully store painted parts so as to prevent them from being scratched. I placed a paper towel at the bottom of a plastic storage bin then place the parts in it so they are not touching. 

I painted the main chassis with Dupli-Color HWP101 Silver High Performance Wheel Paint, this paint is durable and has texture which hides surface imperfections. I carefully masked off all components that I didn't want painted. In addition, I masked off the component side of the chassis. I didn't paint the component side of the chassis because many components are electrically grounded to it, paint is not conductive. As before, I suspended the chassis with magnet wire, allowing me to paint all surfaces and then hanging to dry. Please see my slideshow below for a pictorial view of the steps. ​

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I typically use Dupli-Color Wheel Paint when painting vintage radio chassis. This paint is durable and has texture which hides surface imperfections.

The brass mounts that hold the carry handle to the Heathkit XR-1L case were badly corroded. First I lightly sand them and then painted them gold. I used a test lead with alligator clip to hold them while they were being painted. 

I used a sharp bamboo stick to paint the dial scales on both the Tuning and Power/Volume knobs. I used Acrylic Enamel Gold paint that I have on hand for my model railroad hobby.

Step 6 Chassis Assembly

First, I had to attached all ground lugs, terminal strips, and speaker standoffs with the original screws, nuts, and lock washers. Four of the screws also server double-duty and hold the audio and interface transformers in place. The screws holding these items in place were removed for paint. Next, I had to solder the wires connected to the audio and interface transformers to the proper points on the terminal strips.

The Tuning capacitor needs to be installed to the left side panel first. Then the side panel can be attach to the chassis with three screws. I had to install a solder lug, circled below, as the painted side panel will electrically isolate the frame of this air capacitor from the chassis. Once the side panel is attached to the chassis, I will run a wire from this solder lug to a chassis ground point.

Here is a picture of the chassis with both left and right side panels attached. The Power/Volume control, circled below, was attached to the right side panel after it was attached to the chassis with three screws. In addition, I installed the loopstick antenna to the top of the chassis.

Time to install the ground connection between the Tuning capacitor and the chassis. I circled in red the soldered endpoints for this connection. At this point I also soldered the rest of the connections to the Tuning capacitor and the loopstick antenna, these connections are circled in yellow. Note: There are other connections to the Tuning capacitor and loopstick antenna on the other side of the chassis that are not displayed in the picture below.

The audio transformer's wires are then soldered to the speaker terminals.

The speaker is mounted to standoffs, attached to the chassis, with screws. 

I decided to attach a 9 Volt battery clip to the battery terminals. This allows me to power my Heathkit XR-1L radio by either a 9 Volt battery or six D batteries, as originally intended. 

I cut a rectangular piece of packing foam that fits the height and depth of the battery compartment. I then cut a rectangular opening in the center just big enough to hold the 9 Volt battery snuggly. Picture below is the 9 Volt battery in its newly constructed holder.

Step 7 Final Testing and Alignment

It is always a good idea to test electronics before buttoning it back up into their enclosure. In addition, I wanted to check the alignment of this radio as it was built from a kit. The Heathkit XR-1L radio can be aligned without any special equipment. Before performing the alignment, I installed the transistors in their appropriate sockets. Here are the alignment steps I used, based on my experience with Superheterodyne radios. It differs slightly from the official Heathkit XR-1L alignment procedure. 

1. Turn the Heathkit XR-1L radio on, set the volume control mid range.
2. Tune in a weak radio station, adjust the ferrite slugs in the three IF Transformers for maximum volume of the radio station from the speaker. Adjust IF Transformers in this order: Top Left, Bottom Left, Right. 
3. Repeat step 2 a second time to ensure correct adjustment. 
4. Find a station of known frequency on the high end of the dial (around 1400Khz or higher). Adjust the tuning dial to read the appropriate marking for the station's frequency. Now adjust the trimmer on the tuning capacitor that is closest to the side panel it is mounted on until you hear the same station again.
5. Find a station of known frequency on the low end of the dial (around 600Khz or lower). Adjust the tuning dial to read the appropriate marking for the station's frequency. Now adjust the slug of the local oscillator coil, directly above the two IF transformers, until you hear the same station again.
6. Repeat steps 4 and 5 again to ensure correct adjustment.
7. The last step is to adjust the antenna trimmer. Find a station around midpoint on the tuning dial. Now adjust the trimmer on the tuning capacitor that is farthest from the side panel it is mounted on until the station is loudest from the speaker.

Step 8 Install Chassis

The last major step is to install the chassis into its leather case. First, I treated the leather case with Meguiar's Rich Leather Conditioner. I have many Meguiar's automotive products on hand for use on my automobiles. 

The original formed leather handle was missing from my Heathkit XR-1L radio, I assume it rotted away many years ago. I found a suitable guitar amp leather carry handle on Amazon that will do nicely. The replacement leather handle matches the cream color of the Tuning and Power/Volume control knobs. 

I cut off the original chrome mounts of the replacement leather handle with a Dremel cut-off saw. I then fashioned handle connecting rings using cloth coated wire painted gold. I then soldered the ends of the cloth coated wire together. The soldered ends will be concealed in the brass mounts attached to the leather case.

The brass mounts that connect to the leather carry handle have clips that pass through the leather case. The clips are then bent over to secure them to the case.

Here is a picture of the replacement leather strap installed.

Finally, the chassis can be installed in the case. It is held in place by two screws. I have circled where the screws are installed.

Here is a picture of my newly restored Heathkit XR-1L.

My newly restored Heathkit XR-1L AM Radio in action!