Ken's Antique Radios

Ken's Antique Radios My name is Ken and I am an old school electronics hobbyist. I refurbish vintage radios and give them a second life and also saving them from being tossed.
(1)

If you need help in reviving your vintage radio. Contact me (text only) at cell 604-817-6339. I am an old school electronic hobbyist. It's my passion to restore vintage tube radios and amplifiers to as close to the original condition as I can. I pay attention to details. Wood cabinets will be re-furbished and some stripped to bare wood and re-stained and varnished depending on the condition. Bakelite and plastic cases will be polished to expose its original shine. in some cases they may be repainted. Cracks will be repaired with epoxy to prevent further development. Out-of-spec components will be replaced as needed. "Stuffing" technique is used in some higher end antique radios to retain its originality. It is a time consuming process in which new parts will be hidden inside the original can or shell to make them look original. My mission is to revive dead and abandoned vintage radios in order to give them a second life. I can also add a cable by request so you can play your phone/iPod/Bluetooth through the radio.

Electronics restoration of 1956 Motorola Model 56M portable AC/battery radio. This very nice little radio was mad...
09/14/2026

Electronics restoration of 1956 Motorola Model 56M portable AC/battery radio.
This very nice little radio was made by Motorola of USA. The case is pressed tin with leatherette cover. The original A battery (7.5 V) and B battery (90V) has been obsolete for many years. It is also 120 Vac powered. The plugs and wires for batteries hook up are not necessary anymore and I have removed them totally.
The plastic carrying handle has the antenna coil loop inside because it cannot be inside a metal case which shields off the radio wave. The PCB (printed circuit board) is used as chassis. It has copper trace on both sides making difficult to trace the circuitry. Personally I hate working on PCBs. The electrolytic capacitor can contains 80uf-150v, 60uf-150v, 400uf-15v. It is a pain in the behind to remove since there are 3 connectors and 3 hold down prongs that have to be heated up to melt the solder, simultaneously at the same time. The copper trace will usually be damaged during the process. It is also an oversight trap that the 3 hold down prongs are connected to ground and the aluminum can is used for conductivity, so they must be all connected to ground after the can is removed. Three separate electrolytic caps are used to replace it. There are 3 resistors have drifted in value and replaced.
Tube lineup is 1R5, 1U4, 1U5 and 3V4, and 3V4 is the only survivor. 1R5 tested dead and replaced with a Hitachi (59%/59%), 1U4 tested dead and replaced with RCA (74%), 1U5 tested at 26/6 and replaced with a Hitray (78%/74%). It is rather unusual that 3 of 4 tubes need replaced.
There are 2 pins for the 120 Vac connection, the power cord is missing. I soldered the cord to the pins for test run. As usual, an AC amp meter is connection to monitor the AC current draw and the Variac is set at 85 Vac. Radio makes no sound until the Variac is cranked up to about 100 Vac. The mixer tube will not oscillate when the heater voltage is too low. The radio makes a loud rumbling noise and later I found out that one of the filter caps is not properly grounded.
The radio works very well and fairly powerful considering it uses the low power miniature tubes. A quick alignment is performed.
The case is cleaned with VLR (Vinyl Leather Rubber) and the chrome face plate is polished with Brasso. Since the power cord is missing and it is near impossible to find a replacement, even if I can find one on eBay, it will probably cost me a limb. I decided to fabricate one using the parts from a 6 pin 6E5 magic eye socket. The pins of the 6E5 tube are the same size as the AC connection pins in this radio. After some cosmetic dressing and the plugs color marked for L - live and N - Neutral. It works just fine. I always like to polarized the AC to minimize danger of hot chassis, especially for this radio with metal enclosure.
It is a fun project bringing this 70 year old little guy back to life.

Electronic restoration of 1948 Zenith model 6G801 portable battery /AC radio. A lady contacted me on my FB site ab...
09/08/2026

Electronic restoration of 1948 Zenith model 6G801 portable battery /AC radio.
A lady contacted me on my FB site about donating an antique radio to me. Before I even asked for the location where I can pick up, she offered to deliver to me. I admired her passion about keeping these beautiful antique radios from going to the city dump.
Jacquie D. drove for an hour from N. Vancouver to Coquitlam (a suburb of Vancouver, BC) where I am located. It was love at first sight, of course I mean the radio. It has a plastic case and by pushing a button the front doors will be "pop open" and the back panel will pop up, the radio will be on automatically. This is like the toy "Transformer" which will change its appearance to entirely different thing. I promised her I will bring her back to life and feature her in my Face Book site so she can view how it is done during the whole restoration process.
After a short queue up, it is her turn to get on my work bench. This radio is made by Zenith, the same company that produced the iconic Trans Oceanic multi band portable battery/AC radios. As commented by my mentor, I am always a fan of odd ball, rare radios. This one is no exception. It is the first one that I have come across. The aluminum chassis is carefully pulled from the plastic case. The inside is in fairly clean condition. All Loctal tubes used except the power tube 3Q5. They are just like their name, they lock in place in the socket to withstand movement or bouncing. They were used in portable radios, transmitters, automobiles and military equipment. They were made by Sylvania. The centre pin or key is locked in place in the tube socket. Underneath the chassis, there is a lot of paper/wax capacitors and a electrolytic multi cap that has 60uf-150v, 40uf-150v, 20uf-150v and a 200uf- 25v inside a single can. I immediately know that I have to deal with the limited space for the 4 replacement caps. A wire wound voltage dropping power resistor has its enclosure burnt and turned into crumbs as shown in one of the photos.
All tubes pulled and tested in my Knight 600 tester. Tube line up: 1LN5, 1LA6, 1LN5, 1LH4 and 3Q5 plus a Selenium rectifier. Usually for a portable radio, 4 tubes are enough, the 5th one will give the extra oomph in boosting the radio wave. Also the larger Loctal tubes are more powerful than the smaller 7-pin miniature tubes. So I would expect nothing less than a more powerful portable radio than a typical Trans Oceanic. The large speaker (5.3") is designed to handle the output power.
All tubes tested strong, except a weak (22%) 1LN5 which I would use for test run and replace later. There is a great number of paper/wax capacitors. I have painstakingly swapped them out one by one. The ones hidden deep inside are hard to retrieve. The single 4-plex electrolytic capacitors will need 4 individual ones to replace since a straight replacement is not available anymore. It imposes some headache where can I find the space in this clustered chassis. Two of them are Epoxy glued behind the speaker and above the (R9) 950 ohm/(R10) 950 ohm Candohm resistor. Heat dissipation is not a problem for the Candohm since it is riveted to the aluminum chassis. As shown in one of the photos, the voltage dropping (R6) 140 Ohm wire wound resistor has its ceramic or Teflon body burnt and disintegrated. I replaced it with a 125 Ohm+ 15 Ohm = 140 Ohm 7 W wire wound ceramic one which we called "white coffin".
The rest of the resistors checked for the allowable tolerance, it is important particularly for battery/AC radios because some of the resistors are in the heater network. A drop in resistance may cause the voltage to rise and heater blown since the heaters are only 1.4 volt. After hooking up the antenna coil built in the enclosure, she is now ready for test run. A Variac is used with an Ampere Meter connected in the AC line to monitor the AC draw. The AC current draw is very little considering it can also energized by dry batteries, so the electric consumption is very low. I started with 85 Vac and there is no sound. Obviously, the heater voltage may be less than 0.8 volt and it is not enough to generate heat. The converter 1LA6 may not even oscillate with the low heater voltage.
I continue to crank it up to 100 Vac and the radio starts to make noise.
Experience tells me that the contacts in the Variable Air Condenser of all antique radios need a good cleaning with Silicone base contact cleaner to remove the surface oxidation which may not be visible. The radio is very sensitive and powerful and sound quality is excellent.
Next will be the clean up on the plastic case. The dirt collected in the lines and crevices are cleaned off using Mr. Clean solution and a tooth brush. All hinges l**ed with 4 in 1 l**e oil. The pop up antenna panel in the back is not working properly. Grease is applied lightly to the retainer spring wire and all sliding surfaces l**ed.
The button in the front when pushed, the front doors will pop open, back panel pop up and radio will be on automatically. It will turn itself off when the doors are shut.
This is a fun project to say the least. Somewhat challenging. I am glad that I can bring this beauty back to life after sitting mute for decades.
Special thanks to Jacquie D. for donating this unique radio and giving me the chance to work on it.

Cosmetic refurbishing and electronic restoration of 1931 DeForest model "Encore" Model Type 500 chassis radio. I...
08/19/2026

Cosmetic refurbishing and electronic restoration of 1931 DeForest model "Encore" Model Type 500 chassis radio.
I received an inquiry from Sommer B. who wants me to look at her heirloom radio that has been with the family for over 60 years. She sent me a few photos of the radio but I cannot find the model number anywhere. I need to look at the schematic before I can assess the radio and give her my opinion. There is a label of Jones and Cross Ltd. Edmonton where the radio was purchased. Later Sommer confirmed that the radio was originally bought in Edmonton by the grand parents of his hubby Craig, and was brought here to Vancouver, BC. They are wondering if the cabinet can be refurbished for decoration or she should be electronically restored as well. I immediately advised her that she deserved a full restoration both cosmetically and electronically because of the rich family history.
The 1st few photos show the state she was in. Speaker cloth was ripped. The cabinet was in bare wood after someone in their family stripped the paint finish. All wood k***s are there.
The radio was built like a tank and weights a ton. The overkill power transformer alone probably weights 8 - 10 lbs. The chassis has flanges on both sides and slide inside 2 U-shape channels and cushioned by some foam which has deteriorated over the years.
After some cleaning and polishing, the metal parts shine again like new. A 8uf electrolytic condenser has red copper can which is very unusual when you consider the cost of copper. Its has the value 8 uf 450 v engraved on top instead of printing. There are 6 vacuum tubes: UY235, UY224,UY235, UY224, UY247 and UY280.
These are tubes used in most 1920's sets. Some are the beautiful hot air balloon glass envelop type. Both UY224 are tested DEAD unfortunately. Luckily I have two 24A which I can replace with. UY224, 224, 24, 24A are actually the same tube just marked for different usage. The 24A is an improved version of the original UY224 with faster warm up time and treated plate.
The radio has only 2 electrolytic capacitors being the Red copper one and the paper tube one. They are replaced with 10 uf-450v modern ones about 1/15 of the size. All other capacitors replaced. Some "dog bone" resistors have drifted beyond 15% and replaced accordingly. The output transformer is found dangling and not fastened down to the chassis.
The good thing about working on 1920s to early 1930s radio is the generous space under the chassis that make it easier to work, but the tough part is to chase the wiring and ID the parts. Engineers designed things differently 95 years ago. American tends to use thick cotton jacket wires with oversize gauge conductors while German radios have thinner gauge wires just enough to carry the current according to the German engineering.
Hazeltine Corp. was an American communications company since 1924 and has gone through different changes and ownership. I will leave it up to you to research its history which is quite interesting. A great deal of time has been spent on tracing the wiring and identifying the resistors and capacitors. A few "dog bone" resistors have drifted in values and replaced with new ones nearly 1/20th of their size.
After the recap job has been completed, I have to pull the 8" field coil speaker from the cabinet to facilitate test run. The speaker is in excellent condition even has a shroud to protect the paper cone which is rarely seen. Since the speaker is out of the cabinet, its a good chance to work on the cabinet and speaker cloth at same time. The cabinet is so nicely stripped, all I have to do is to sand it down so slightly with 800 grit sand paper and apply a very thin coat of "traditional cherry" stain. It soaks up the stain like a sponge. After a couple of days of drying, 2 -3 coats of high gloss clear varnish is applied to the k***s, copper bezel plate and re attached. Four rubber feet also installed. I have picked a bright gold color cloth with floral design for speaker grille cloth. It is stretched and attached to the mounting board with 5 minute Epoxy. The last photo shows the final product. This old lady retains her original beauty like 95 years ago.
Radios of this era are always thirsty for strong radio signal. If you are old enough, you may remember seeing the external antennae on top of buildings everywhere. They could look like a long copper wire suspended by ceramic insulators at both ends, or wires wound around a cross shape wood frame and look like a big spider web. With the improved transmitting power of radio stations, we can do with just a long piece of spread out wire. As a trick for radio technicians, I stapled a wire on the underside of the cabinet to act as antenna. It looks like the heating element of an oven. I choose to do this as added value to the radio.
After hooking up the AC draw current meter, the power is gradually increased from 85 vac with an Variac. Radios this era do take much longer warm up time due to the lower 2.5 V heater voltage. The AC current draw is around 0.6 Amp which is normal. I was testing the radio with a short external hooked up to make sure she has got enough oomph to jump start. After a few stretching and yawning, she comes to life. The volume control controls how much radio wave is grounding, the less grounding the louder she sounds.
All plate voltages measured to be acceptable and the power consumption holds steady. I hooked up a signal generator and inject a 600 KC and then a 1300 KC signal and adjust the 3 padding condensers to obtain maximum output. The radios is quite powerful even with just the DIY built in antenna wire.
Now I am ready to slide the heavy chassis back to the cabinet. I cut up couple of rubber strips that I cut from the inner tube of truck tire to 1" wide by 5" long and wrap them along the flanges on both sides of the chassis for cushioning.
The radio is ready to come home to Sommer B family where she has sit mute for the last 60 odd years. I hope Granny is ecstatic to see her childhood radio back to life again. I am grateful to have the chance of working on this beautiful heirloom radio.
The satisfaction is priceless.
Kim finally came to pick up her childhood company, except this time she is no mute, she sings beautifully. I just realized that Kim stripped the re painted (literally) finish herself when she was a teenager. She has done such fantastic job that makes it easy for me to refurbish.
See last photo of another satisfying customer with her beloved 95 year old resurrected antique radio.

Electronic restoration of 1939 Stromberg Carlson model 335-L console radio. Customer Sam W. brought in this lovel...
07/28/2026

Electronic restoration of 1939 Stromberg Carlson model 335-L console radio.
Customer Sam W. brought in this lovely 87 year old console radio for electronic restoration. The radio cabinet is in VG condition with original speaker grille cloth, k***s and bezel plate. Stromberg Carlson is one of my favorite American made radios. They built strong, attention to details and consideration for future repair etc.
The chassis is fastened down with rubber padded grommets in 4 corners for absorbing any shock. However, the rubber did get hardened after 87 years. I like the steel inverted U shape bar that holds the push button block which acts as carrying handle and a stand when the chassis is inverted. I wish German radios are designed with this helpful feature in mind. On the other hand, German radios are the worse when it comes to inverting the chassis. One has to fabricate a custom "rotisserie" to hold the chassis in place when inverted, or the chassis will be supported by the dial glass. The radio has 7 vacuum tubes (6A8, 6K7, 6H6,, 6F5, 6U5, 6F6 and 5U4) The original schematic shows an 80 rectifier and this radio is using a 5U4 instead.
The under chassis is pretty crowded with all kinds of paper/wax capacitors and electrolytic caps that were used to replace the aluminum cans. Second and third photos show the BEFORE and AFTER condition. One big paper/wax 0.025 uf capacitor was replaced but not removed due to its fastened down with strap and rivets. The 4th photo shows a parade of casualties. There is a couple of "dog bone" resistors which still holding their values, so they stay. As a normal practice, all tubes are tested: 6A8- 68/69%, 6K7-70%, 6H6-26/22%, 6F5-59%, 6F6-75%, 5U4 69/68%, 6U5 bright. Since I don't have a 6H6 on hand, I will use it for test run and will replace it later.
The gigantic 12" field coil speaker is in excellent condition and extricated from the cabinet to facilitate test run of the radio on the bench. An AC current meter is hooked up to monitor the main AC draw, and it hangs around 0.6 Amp which is normal. The selector switch is cleaned with contact cleaner. The radio comes to life without a hitch. Owner wants to add on a pig tail shielded wire with a 3.5mm phone jack to play his gadgets. A swift alignment is performed. All is good to go back into the cabinet. The 6U5 reacts briskly. As I was listening to the radio inside my enclosed garage, I can hear some mild hum regardless of the volume level. Here we go again, both chassis and speaker back to the bench for further tweaking to mitigate the hum.
As I was listening to the radio while it is on the bench with open baffle speaker, I didn't notice the hum which is nearly inaudible, well, otherwise I wouldn't have put them back to the cabinet. Obviously the first thing I suspect is the ripple in the B+, meaning not enough filtering. I have already increased the capacitance from 16uf-16uf to 22uf-33uf. Tried to increase to 33uf-47 uf but no improvement.
Here is a list of what I have done, BUT ALL TO NO AVAIL :
* Add one more stage of filtering using 33uf+3.3K 10w resistor + 47uf right off the gate of 5U4
* Connect in series a silicon diode in the B+ line
* Swapped out 6F5 and 6F6
* Shorted the grid (pin 9) of 6F5 to ground
* Shorted the grid (pin 5) of 6F6 to ground
* Put a grounded shield between the OPT and the volume control
* Add two 0.04 uf 275 Vac safety caps to the AC line (still there)
* Grounding the chassis to the ground of the AC line
* Replacing the Air Cell with a 1.5V AAA dry cell

I have spent enough time and done enough tweaking that I have exhausted all avenue. When the speaker is in the cabinet and I listen in a very quiet environment the low frequency hum is mildly audible. So I surfed the net and try to find out what is an acceptable level hum in the speaker. If the speaker is of bigger diameter and higher sensitivity and contained inside a big cabinet, the hum is usually much amplified than if the speaker is smaller, less sensitive and open baffle. See the last screen shot photo of the post regarding this subject. For acceptable hum , an AC voltage measured across the speaker coil with no sound should be between 5mV ~ 10mV. I tested it at 4.2 mV. I am convinced that " it is what it is" and we just have to live with it. I would just sit back and enjoy the music rather than turning off the sound and stick your ears up trying to listen to the hum.
Conclusion: I have acquired a near new 5Y4 rectifier and swapped it the original one and see if the tube is the culprit. There is no change. Now I suspect the manufacturer's design flaw .
(1) the location of the OPT (output transformer) under the chassis is too close to the power transformer and the volume control with all the AFC components close by. The hum may be caused by magnetic induction.
(2) The field coil of the speaker does not have the "bucking" reverse winding in it. If it does, it may help to reduce or minimize the hum.

Electronic restoration of 1952 Zenith model J615 radio. She has 6 tubes (6BJ6, 12BE6, 6BJ6, 12AT7, 35L6 and 35W4) Ob...
07/13/2026

Electronic restoration of 1952 Zenith model J615 radio.
She has 6 tubes (6BJ6, 12BE6, 6BJ6, 12AT7, 35L6 and 35W4) Obviously this is a strung heaters configuration.
Zenith has some beautiful design radios, this is one that I like. After recapping and checking all other components and tubes. The radio works and sounds great. I decided to install a Bluetooth module with its own PSU to make her BT ready as I have done dozens of times with no problem. As usual, I Epoxied both BT and PSU modules on a piece of cardboard which is also Epoxied on top of the now defunct Electrolytic cap. I like to see the two little blue light LEDs when its turned on.
A mini toggle switch with 2 position 2 pole is installed on the back panel. I like use the mini toggle for its size, price, function and easy installation by drilling a 1/4" diameter hole. When it is switched to play BT, it will connect to 120Vac main, disengage signal from radio and engage signal from the BT. It is a very practical and effective way IMO. So far so good, it seems everything went well. Both radio and BT play very well when needed. The joy was short lived. when I listened to the radio, the music is good but it has a constant .....tick...tick.....tick...tick sound at a frequency of about every 0.5 ~ 0.75 second. The sound occurs across the whole spectrum with or without station tuned in. The sound is controlled by the volume pot, that tells me that the sound comes from the front stages precedented 12AT7 and 35L6.
At first, I thought this is no big deal. I back tracked to double check all the parts put in. Traced all the wirings, test all resistors for drifting but to no avail. I plugged the radio to a different wall socket, sound is till there. I turned off the light, incandescent or LEDs, the sound is still there. I tried to ground the grids of the first 3 (RF) tubes, sure enough as soon as I grounded the grid (pin 1) of the first 6BJ6, there is no sound. So I think the culprit is in the 1st stage. I shorted out the antenna coil to see if the interference is from the atmosphere, but the sound is still there. Now I realize that I am going down the rabbit hole. After a few days of tweaking and lost a couple of night sleep, I am not getting anywhere and decided to seek help from another antique radio repair discussion forum. Some more experienced tech suggested that I should post a short video clip to show what the ...tick....tick....tick.... sound like. There is no better place to post the short video clip than here so all my viewers can also "enjoy" the sound which I call "noise" (view and listen to the last photo)
I cannot remember if the ....tick...tick....tick.... noise was there before I added on the BT module or after. I decided to remove both the BT and PSU modules totally and re check. Surprise, surprise, the noise has gone.
Now I have to conduct a post mortem to find out what did I do wrong to cause this oscillation. The last 2 photos show the schematic and a 3D diagram of how I wired the lead wires from the BT module to the radio. Pay attention to how I grounded the shield of the shielded wires. I was too casual to ground the shielded wires creating a loop around circuit which causes the oscillation IMO, but I can't understand why. Especially this happens even when the BT module is not powered up. I created my own problem so to speak. However, I am not giving up the idea of retrofitting the BT module as I have done to other radios dozens of time. I will re connect the BT module in a different manner and see what result I will get.
SEQUEL to this write up on the mysterious "pulsating" noise. Since there is lots of possibilities to go around for causing this noise, I start to diagnose the problem using process of elimination.
(1) I disconnected and removed all the shielded signal wires just leaving the the 120vac wires connected to the PSU module with the on/off toggle in series. The noise is gone. But when I connect either the signal wire or the ground wire from the BT to the radio, the noise comes back. Please note that the PSU is on OFF position at this time, that means the BT is not even powered up.
(2) I suspect the BT/PSU combo module is faulty, so I built another one using the same model of BT and PSU (see photo) and wired it up without using shielded wires. The noise is still there, so the faulty BT/PSU combo theory is eliminated.
(3) I built another BT/PSU combo but this time using a different model PT (model XFW-BT) on a red color PCB, and wired it in but the noise is still there while the radio is played.
(4) After reading a few discussion forum, it is suspected that the PSU is tapped into the same main of the AA5 radio and share the same Neutral line of the main which will cause pulsation and an isolation transformer should be used. So I connected a 120vac/120vac isolation transformer for the PSU, but the noise is still there when the radio is on and even when the BT/PSU is OFF.
AS LONG AS EITHER THE SIGNAL WIRE OR GROUND WIRE OF THE BT MODULE IS CONNECTED TO THE RADIO, THE PULSATING NOISE IS THERE EVEN WHEN THE BT MODULE IS NOT POWERED UP.
Conclusion: None.
The root of the cause of this pulsating noise is not found. There is a gremlin inside this radio that doesn't want me to retrofit a BT in her. I am moving on to the next project.

Electronic restoration of Philco Model 42-360 floor radio.After viewing my post on FBMK, Sam W. came to purchase a radio...
07/09/2026

Electronic restoration of Philco Model 42-360 floor radio.
After viewing my post on FBMK, Sam W. came to purchase a radio that I have posted for sale. He ended up purchasing 3 of my high end antique radios from my own collection, including a 1929 Radiola 18 which I have refurbished both electronically and cosmetically. He will use it to drive his 1600 Ohm horn speaker.
The sale did not end here. He then carried in a very nice 1942 Philco Model 42-360 floor radio that his father purchased from a garage sale in his neighborhood. The wood case is in amazing condition with no scratches, coffee cup or cigarette burn marks. All k***s are original and the plastic bezel plate has maintained its original shape. Needless to say the chassis has its share of 84 years of dust collection. She employs 7 vacuum tubes : XXL, XXL, 7B7,7B7, 7C6, 41 and 84 rectifier. The power transformer is massive. As part of my routine restoration process, all tubes and pulled for testing to make room for chassis cleaning. The tube test results are recorded. They are the original Philco Loctal tubes, except 42 and 84. Philco is specialized in designing radio receivers used in the military and auto industry. The Loctal tubes can withstand vibration and the bouncing motion of the units they were in. When these Loctal tubes are pulled from the socket, one can push on the glass envelop on the pimple mark side of the metal base and dislodge it. However, some may say the opposite way works.
All tubes are tested above average, except the 84 rectifier which only has 13 and 22% emission.
All paper/wax condensers and 3 electrolytic caps are replaced. An unusual number of condensers are used in this radio and they are replaced one by one. I have noticed that the steel wires used in making the pins of these Loctal tubes are of high tensile steel and always show a dark and glossy surface and they need to be polished by say, #400-600 W/D sand paper to expose better contact surface. This is particularly important for the heater pins. The heater may not light up if the conductivity is poor.
A lot of time spent swapping out all the capacitors. Photos show the BEFORE and AFTER condition of the under chassis. To test run the chassis, I have to extricate both speaker and the big heavy wire antenna coil and put them on the bench and hooked up with jumper wire with alligator clips.
After hooking up an AC ampere meter in the 120vac main, the unit is observed drawing about 0.3 Amp which is normal. After some tweaking, the unit comes to life. Upon checking the rectified DC B+ after 84 tube, it is only 250 Vdc instead of 320 Vdc as shown the the schematic. The plate voltage of 41 tube is 117 Vdc instead of 180 Vdc, and Grid 2 is 128 Vdc instead of 190 Vdc. The radio still works but a bit under power. This is not unexpected knowing that the rectifier tube 84 is tired and not pumping out adequate voltage.
To make the case even worse is the existing 8" speaker has a field coil resistant of 4,000 ohms while the original speaker is 1,700 Ohms which drops the voltage even more. The rectifier tube 84 is an odd ball tube and hard to find. I have decided to bypass it using two FR207 diodes and achieve full wave rectification. To compare the two methods, 84 pumps out 325V 60mA while FR207 pumps out 1000 V 2 Amp at a fraction of the cost. The 84 remains in its socket to show originality.
Now I can see the difference, I am getting 336 Vdc after the FR207. 41 tube has 167 Vdc on plate and 176 Vdc on Grid two. The radio sounds powerful, reception is great. To maximize its performance, an alignment is performed.
This 84 year beauty is singing again after sitting mute for God knows how many years. Sam and his father should be happy to see the radio resurrected. Moving on to the next project.

Electronic restoration and retrofitting of Bluetooth of 1951 Crosley D-25 table top clock radio. Kevin, one of my cu...
06/06/2026

Electronic restoration and retrofitting of Bluetooth of 1951 Crosley D-25 table top clock radio.
Kevin, one of my customers, brought me a very nice looking clock radio made by Crosley. This model is very popular among collectors and antique radio enthusiasts. There are many colors to suit your taste, White, tan, chartreuse, maroon, metallic blue and green. This one is maroon color. All k***s are intact, even the 3 little ones on the clock side which is unusual. Its dash board face makes it so well liked. I have restored at least ten of these babies. The clock is always reliable and seldom gives me trouble. As a matter of fact, I like AC clocks more than the modern battery operated quartz movement clocks. If you have a few of these battery operated clocks in your home, take turn replacing the batteries could be a pain in the behind.
One has to be careful pulling the chassis out from the case. There are about 6 wires need to be disconnected and they should be marked. There is an exterior AC plug on the right side and a bit tricky to dislodge. The chassis is dusty and a bit grimy which is quite normal. Underneath the chassis is quite crowded due to the use of the big old wax paper capacitors. All tubes are tested to be good. There are the usual 3 electrolytic caps in one cylindrical can as shown in the picture. They are replaced with individual ones. All paper wax capacitors are also swapped out. Most of the resistors are tested within 15% of the original values.
Kevin wants to add on a Bluetooth module for playing Spotify music from his cell phone. The top of the original electrolytic capacitor is an ideal place for the BT module where I epoxied it in place. I use a "wall wart" 5 Vdc adaptor as the power supply and Zip tied it on top of the speaker magnet. A 2 position 2 pole mini toggle switch is used for switching the BT module on and off and also selection of Radio and Bluetooth. I choose the mini toggle switch instead of the slider switch is because it will be easier to drill a 1/4" diameter in the back cover than to make an oblong hole. The last picture shows where it is located and marked for its function.
The retrofitting of the BT module will not interfere with the function of the original RCA phono jack in the back. The radio works great and so is the retrofitted BT. So the project goes off without a hitch. Now Kevin can sit back and enjoy the radio or music from Spotify on his cell phone.

Address

Coquitlam, BC

Telephone

+16048176339

Website

Alerts

Be the first to know and let us send you an email when Ken's Antique Radios posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The Business

Send a message to Ken's Antique Radios:

Shortcuts

Share

Category