Behind the White Wheel

Behind the White Wheel

Saturday, April 4, 2015

Becker Mexico Alive

After rebuilding the power supply, time came to rebuild the radio. Again, these units are made of simple electronics components (resistors, capacitors and some semi-conductors) in addition to the tubes. The Becker Mexico contains 7 tubes and complex circuits that are much difficult to follow without the correct schematics. 

The Becker Mexico view from above; 2 tubes and the Wunderbar mechanism are visible
Thanks to Jeff Miller for posting on www.mbzponton.org the schematics of the various Becker Tube radios (Mexico, Brescia, Europa and LeMans), without them I couldn’t perform any reparation accurately. 

Here is a quick history of the Becker Mexico installed in my car:
  1.  I bought it in 1999 from a retired taxi driver who had kept it for more than 35 years untouched, unused to replace the original Becker LeMans (AM, LW) radio which was beyond reparation
  2. I was 19 back then and had only very basic knowledge in electronics, no schematics and no testers. I only had a soldering iron and an ohmmeter. To my luck, visually a tube was broken (replaced it), cleaned the vibrator pins and plugged in the radio listening to beautiful music.
  3. I changed the power supply's vibrator in 2004 after finding a solid state replacement in Canada.
  4. The radio worked well from 1999 up till 2014 when problems started appearing:
              a-      The radio’s sound started becoming unclear (bad quality of sound)  
              b-      Then the Wunderbar (automatic electromechanical search system) stopped detecting any  station              
              c-       Finally, the radio died on the FM band followed by an extremely weak AM reception

I sent the radio to two repairmen (one of them mentioned in a previous article on this blog) who both failed to do the repair after leaving it at their shops for more than a month; I lost hope and decided to give it a try myself.
I started by studying well the schematics; understanding the different currents, how things work and how the radio is designed. I was lucky enough to find a very interesting website on old radios’ restoration (http://antiqueradio.org) that Philip Nelson runs. I exchanged few emails with Phil who suggested I start by replacing all the electrolytic and paper capacitors and see if anything changes.
The radio contains the following electrolytic capacitors:
  • One 50uF 350V
  • Two 10uF 25V
  • One 5uF 30V
  • One 100uF 25V
Replacements were easily found and installed; of course the new capacitors are much smaller making their installation easier than expected. 

100uF new electrolytic capacitor installed
New 4.7uF electrolytic capacitor installed
After replacing these capacitors I turned on the radio to only hear a hum from the speaker.
I continued recapping and changed the several 0.022uF and 0.01uF paper capacitors; the replacements are the smaller much more efficient orange and green drop models that are not polarity sensitive (no + or – connections as the electrolytic ones).
Green drop newly installed capacitors along with an electrolytic one
Orange drop newly installed capacitors
On a side note, always make sure to install the new capacitors in a way that makes them look nice in these “board-less” circuits.
Once this job done, I powered the radio without succeeding in getting anything different than the “hum” on the AM and very far FM reception (barely noticeable and accompanied by the hum).
At this stage I was starting to lose hope; the resistors were the only left components that I didn’t test thoroughly; the tubes were out of any suspicion since I tested them all on my working Blaupunkt Santos radio.  
Before doing so, and to get an idea on the status of the old capacitors, I placed each old one on the tester only to discover that the 100uF capacitor had drifted in value to 500uF and the 50uF one was shorted. 

The old paper and electrolytic replaced capacitors; notice the bottom of the Blaupunkt Santos tube radio
I took few days off then started again examining the values of the many resistors. After 3 long hours of examining and noting values, I found a 500K resistor that seemed completely open! This resistor (R104 on the diagram) connects Tubes EF89 to ECC85 indirectly; hence it plays a major role in the FM Band’s operation.   

The famous 500K dead resistor
100K resistors were the closest I found among the ones I had on hand; I connected 5 of them in series, soldered them to the respective points and powered up the radio…Eureka! Music was heard on the FM with very strong reception and excellent quality of sound!

5 x 100K resistors installed temporarily in series. Notice the 6 new orange drop capacitors
and the new 47uF electrolytic capacitor
5 x 100K resistors installed temporarily in series. Notice the 6 new orange drop capacitors
and the new 47uF electrolytic capacitor
I bought few 500K resistors, installed one adequately and started tackling the AM issue. The AM issue wasn’t as difficult as expected; a good hour spent on testing resistors showed that a well hidden (under many wires and other components) resistor R9 (70K - 2W) was completely fried! I wasn’t surprised when I found out that, especially that it is directly connected to the 50uF capacitor which was shorted. I changed the fried resistor and got strong signal on the AM.

70K Ohms (2W)  fried resistor
Finally, I addressed the Wunderbar issue which was extremely easy as it needed a bit of calibration (calibrating potentiometers P2 & P3 and variable capacitor C126) as indicated in the second page of the radio's schematics. 

Rheostat P3 surrounded by 2 resistors. Watch out this area as it contains high voltage 
(Photo courtesy Becker Autosound)
I tested the radio for few hours and was very satisfied with its performance. I lubed the Wunderbar mechanism, assembled it all and installed it in my car ready for additional years of playing music...
To conclude on this Becker Mexico Tube Radio adventure; I can say that most of these radios are easily repairable and can live for so many years. All what one needs is some logic, basic electronic knowledge (resistors, capacitors), specific testers, a soldering iron and a lot of patience. I admit it was a challenging project/ job to complete but on the other hand, I learned a lot and covered an additional aspect of maintaining my car and all of its components in a perfect shape. 

Enjoying the sound of the Becker Mexico Tube Radio

Wednesday, April 1, 2015

Rebuilding the Becker Power Supply


The Becker tube radios that fit the Mercedes-Benz pontons and other models are composed of two pieces: The radio itself and a heavy power supply that is mounted under the dashboard. The two are connected via a thick cable. 


A diagram showing each component of the 1950's Becker Sound System 
(Ref: mbzponton.org) 
The power supply as it appears
As a start, let’s talk about the role and the components of the power supply:
The power supply contains 2 transformers (1 big and 1 small), a buzzer or vibrator (a metallic can that has 6 pins, a vacuum tube (EL84), a 50uF capacitor (in a metallic can too) and a selenium semi conductor unit in addition to many paper capacitors and resistors. The power supply transfers the 12V DC current to 220V AC allowing the several tubes to operate. The radio then sends back the current to the power supply which amplifies it and transfers it to the speaker for the final output (music, news...etc.) 
The power supply is a critical component for the correct operation of these radios; hence rebuilding it is always a necessity.

Big transformer (from 12V to 220V) - small amplifier transformer - vibrator removed in this pic
As a rule of thumb, all paper/ can capacitors should be changed, regardless of what they measure on the capacitors’ tester. If they still haven’t failed, these 50+ years old capacitors will soon do.
Luckily, they are all still available, much smaller in size and much more efficient.
As a start, the first capacitor to replace is the big 50uF can capacitor. The available replacement measures 47uF, which is OK. 

Here is the new (much smaller) 47uF capacitor installed (brown). I kept the old capacitor in its place (far left) for the purpose of originality of appearance
Then comes the time to replace the 100uF ones; always make sure that the voltage on the new capacitors is equal to or more than that on the replaced ones. 

100uF electrolyte and 0.022uF paper capacitors before replacement (in red boxes)
...and after replacement
Finally, I replaced two 0.022uF paper capacitors that both played a role in determining the quality of the sound.
I took the opportunity to test the capacitors I took off and they all tested badly; some of them were even shorted! 
After replacing the capacitors and installing them in what I see as an artistic and safe way, time came to tackle the vibrator issue. For this problem, two choices are available; a permanent one – which is to buy a new solid state vibrator from several online suppliers (much recommended) and a temporary one – which is to open the can (break it) and clean the vibrator points. Prior to finding the solid state vibrators, I used to clean the points of the old vibrator every other year; fortunately, this is not needed anymore after finding the solid state replacement. 

Solid State Vibrator installed
I had bought earlier this year 3 solid state vibrators, so here it goes; I picked one and installed it in the place of the old Kaco vibrator.
With the capacitors and vibrator replaced, it was time to try to operate the power supply. I didn’t touch the EL84 tube as it looked good and tubes rarely fail in these units.
I connected the working Becker Europa corresponding tube radio, a speaker and a 12V source to the power supply and turned the radio on. Few long seconds passed and the sound started radiating from the speaker. A look at the Ampere-meter showed that the power supply was drawing current much more than it should. A quick test showed that the Selenium Semi Conductor was overheating. 

Replacing the Selenium Semi Conductor
As I still haven’t dealt with such a situation before, I tried swapping it with one from a donor power supply; the result was amazing and the Ampere-meter read something between 1.5 and 2 Amps; the magical current that these radios should draw when in use.
I let the radio play for a moment and verified the new capacitors, the resistors, the new vibrator, the transformers…etc. for any sign of overheating or melting but all seemed fine.

Capacitors, Vibrator, Selenium Semi Conductor that have been replaced
I re-installed the power supply’s cover, tightened the 2 screws and felt proud of having a power supply ready to be used for hopefully another 50+ years …


Saturday, February 28, 2015

The Most Exciting Ride

Today, I was amazed by a picture of an old man getting out of his Mercedes-Benz 180 ponton.

In the middle of nowhere - Beautiful picture of a man getting in or out of his Mercedes-Benz 180
I automatically felt a sort of complicity, a certain relationship between the man and his car. 
As a classic cars enthusiast and owner since the age of 15 (I am now 35) my teenage years, my 20s and now my 30s revolved around engines, gearboxes, paint waxing, chrome cleaning...etc. and most importantly around so many memorable rides with friends and loved ones.
The most remarkable ride was on my wedding's day; I surely never wanted to use my car, but as a good "to be" husband I couldn't say no to my future wife's request...

Driving the famous 100 meters and entering the wedding venue
So here comes the deal after long negotiations; we agreed that I only use my car for the bride and groom's entrance. It was a 100 meters drive into the venue and the 180 would be parked afterwards under my sight during the whole wedding.

Posing next to the Mercedes-Benz 180
When I got into the car along with my bride (she had to suffer to squeeze her long dress), I had strange feelings; stress mixed with joy and excitement...
How will the car "behave"? How will the people react when they see it? Will I be clumsy, as usual, and do some mistakes?

Getting ready for the entrance

I turned on the ignition key, pulled the choke and pressed the starter's button...the engine roared instantly with high idle...Will I have enough time to let the car reach its normal operating temperature so I could push down the choke before entering? I didn't want to drive with a high idle...maybe some cars' freaks guests would notice that and ask me about it...
I can't say a word about the conversation that took place between us; I can't trace it back easily...All I remember was Valerie (our friend and wedding planner) waving and giving us the signal to move forward...

Driving towards the venue; people started staring at us
The entrance was a kind of a complete black out; I remember so many faces looking at us and I remember hearing someone asking me to honk.

Getting in and out of the car wasn't easy for Dona
I turned off the engine and went out of the car...within a fraction of a second, the OCD side in me woke up; I went back in the car and took the key out of the ignition lock...

When I saw the picture, I automatically associated it with that of the old man above
The party started, was awesome and I felt continuously that on this special day, my teenage and early adulthood companion was there adding a special touch to the wedding.


Looking back at the pictures, the complicity I felt between the old man and his 180 was in fact not so different than the one that exists between my 180 and me...It is so far a life long relationship that I hope would continue "till the shadows retire"...


Thank you Nadim BouHabib for the beautiful pictures

Wednesday, December 31, 2014

Before It's Too Late


I have always admired the Mercedes-Benz Fintail series. For some reason; mainly to be able to compete in the US cars’ market and to follow the 1960s trend, Mercedes-Benz “went crazy” and added “wings” or “tails” to the newly designed sedans intended to replace the already aging pontons.

The late style 180b/c ponton overlapped with the Fintail series (Photo: Nadim Bou Habib)

The early 190 Fintail shared the same wheels, front blinkers and grill with the late 180b/c. Notice the wrong star (Photo: Dona Bardawil)
A blue 4 cylinders 190 Sedan
The four cylinders (190 and later 200) and the six cylinders (220S and its variants and the rare 300S) models of the Fintail series, had a successful career and an impressive look. Particularly, the six cylinders models with their big wings and long headlights enclosing the front blinkers had an imposing “attitude”.


The imposing 220S, unlike the 4 cylinders 190, the front blinkers migrated from the rear fenders to the headlights
A rare automatic 220S; notice the beautiful design of the rear wings, the huge taillights and the 13' wheels
Pleanty of room to work on the powerful 220 liters 6 cylinders engine. Notice the dual carburetors
Two years ago; I spotted in Mar Mikhael - Beirut a tired blue with beige interior 220S Fintail. Upon close inspection, the car looked complete with a relatively acceptable interior. However, rust was peacefully and generously eating its body.

Broken headlights glasses and missing star. Notice the rust on the front fenders (Photo: Dona Bardawil)
To my surprise, I found out that the car was for sale; I quickly called the owner who turned out to be living in the building under which the car was parked. An old funny guy, who had bought the car new back in 1963 and used it extensively until he stopped driving due to health reasons.


Rusted trunk, and broken/faded taillights. Notice the reflectors added on the wings (Photo: Dona Bardawil)
I sat in the car, had a look at its engine, trunk and dashboard that surprisingly was still housing the original Becker LeMans AM/ LW tube radio.

Simple and classy 220S dashboard. Unfortunately, the dashboard of our 220S needs a lot of refreshing
2 front seats that can easily accommodate 3 persons; notice the discrete pockets on the front doors interior
Spacious interior and folding arm rest. Notice the wood strips on the doors' interior
I fell in love with the car and found it an excellent candidate for an extensive restoration that would give it back its formal glory; unfortunately, the owner was asking for 5000$ non negotiable, an amount that I found and still find huge for a sedan in a similar condition. 


Missing hubcaps and chrome strips. These strips are very difficult to find (photo: Dona Bardawil)
2012 passed, followed by 2013 and now 2014…Every six months I used to call the owner asking for the price of the car; he never showed any willingness to go lower than 5000$. I hope 2015 would make him change his mind; the car has a history and deserves to be saved.

Thursday, December 11, 2014

Becker Mexico Kaputt

The radio sets originally supplied with the Mercedes-Benz Pontons are, like the cars themselves, of another age. The vacuum tubes need to warm up before the sound begins radiating from the speaker. They are prone to needing repeated adjustments, yet the audio quality is warm and inviting. There is something about sitting in a Ponton at night with the radio on, and hearing the barely audible buzz from the power supply that makes one believe if they were to tune the dial to the right frequency, they would hear voices and music from the past. - www.mbzponton.org - Jeff Miller / April 5, 2002


Back in 1995, when I bought my 1961 Mercedes-Benz 180b ponton, the owner (I respect him tremendously for that) had left the original Becker LeMans radio in the car's trunk.
After restoring my ponton, and being a purist when it comes to original equipment, I deeply wanted to re-install the original Becker LeMans. Unfortunately, the radio wasn't functioning and operated only on the AM and LW bands which were both obsolete. 
These Becker radios operate on vacuum tubes and are composed of two parts: The radio itself and a heavy power supply that is installed under the dashboard. 

Photo: www.mbzponton.org
Time passed by and in 1999, by chance, I found a similar radio in working condition. The radio was a Becker Mexico. I bought it quickly and was amazed when I found that it operates on the FM and AM bands. I installed it in my car and the love story started...

Becker Mexico Tube Radio - the perfect fit
The Becker Mexico with its Wunderbar (Automatic Electromechanical Search System) was a piece of art on its own; it goes perfectly well with the car's dashboard, has a warm and inviting sound and is very practical to use while driving. The driver has to just push the wonderbar and the radio will start searching for different channels and stopping on the strongest one. I enjoyed this Becker Mexico for the past fifteen years up till two months ago when suddenly the Wunderbar stopped finding any station...

I had been used to conduct regular maintenance on the radio; this included cleaning the tubes pins, changing few capacitors in the power supply and replacing the buzzer by a solid state one. Other than these operations, the radio worked very well for the past fifteen years. 

Notice the heavy power supply and the Blaupunkt Santos Tube Radio
With the help of IPOG (International Ponton Owners Group), particularly Jeff Miller who had posted the schematics of these radios on mbzponton.org I was able to get a hint on where to look to try to repair this defect. I changed a resistor and tried to calibrate a capacitor in vain...The Wunderbar would either not work or work sporadically. 

The variable capacitor that I tried adjusting in vain
Yesterday, as I was trying to source some capacitors that I thought might need replacement, I found by chance an old gentleman (Elias Kfoury) who used to repair these radios; he provided me with some additional tips on what to examine and where to look. Unfortunately, my trials all failed; the Wunderbar worked normally briefly and stopped again. I called Elias today, asking him to accept to work on the radio; after many trials and a lot of begging he accepted. 
I will give him the radio by the end of this week or early next week, hoping to get satisfying results. 
I kind of have a positive feeling about it, I have a strong favoritism vis-a-vis old technicians; they are artists who have a certain know-how combined with a very rich experience. They are, "like the pontons themselves, of another age". I enjoy listening to their stories; they are often proud to speak about their experience that makes them remember the "good old days". 

Elias, I am counting on you...I hope to publish a more detailed post once the work is done.

Wednesday, November 26, 2014

To Sabah


Today, the legendary diva Sabah left us…another symbol of the post independence Lebanon disappeared; a symbol of the “trentes glorieuses” era where the young republic and despite all the surrounding turmoil “knew” how to shine and excel.


Sabah, I always long to a beautiful era when I listen to your songs; an era I associate with the many pictures I saw and stories I heard of a certain “موسم عز", a certain short dream that landed once in my village Kfarhata in the early 70s, an era that I feel every time I listen to your beautiful “mawwal” "معنا بعدك و بتضل معنا".

Sabah, in one of your songs, Allo Beirut, you helped me feel, discover and know my city, you increased my love to it, to its people, its streets and its organized chaos. You projected me to moments where I walked around its old streets, listening to some of your songs coming out of Mercedes-Benz ponton and fintail tube radios. 


Sabah, with you gone, a beautiful part of Lebanon’s history ends; a part that I doubt will ever come back again…


Shine in the skies and keep on sweetening our lives with your beautiful voice and smile.