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Radio

This component is part of Radio and Antenna.

Introduction

Radios [German: Rundfunk] were installed in W113 cars at the factory or by local dealers. Factory ordered and installed radios radios were made by Becker but less expensive Blaupunkt radios could be ordered and installed through dealerships. Radio technology was in rapid change in the 1960’s and radio models were changed during the years of Pagoda production. Some radios were monophonic, others were stereo, some with tone and balance, others had European push buttons others had North American buttons.

Examples of documentation that came with original radios

Stereo broadcast was not common in some countries and mono radios were selected.

Some models included a shortwave band which was popular in Europe at the time.

Photos of some radio models are included below. The steps to remove a radio are also presented here.

Content:

Options

If a car was ordered without a radio, a plate with the car model designation (e.g. “230SL”) was installed in the dash in place of the radio. A “Delete Plate” was not common since most cars came with a radio installed. Because of the rarity of these plates, an original Delete Plate commands a high price now. Possible to see asking prices for a good condition original Delete Plate of over $500 (2008).

Becker Radios available from 1963 to 1971 with Data Option Codes.

The Option Code for some radios installed by local dealers at the time of delivery do not appear on the Data Card.

  • 510 Radio Becker Mexico (Olympia with stereo-cassette)
  • 511 Radio Becker Mexico, cassette, full stereo
  • 512 Radio Becker Europa cassette
  • 513 Radio Becker Europa stereo, USA
  • 514 Radio Becker Europa LMKU (LW, AM, SW, FM)
  • 515 Radio Becker AM, FM, USA
  • 516 Radio Becker Grand Prix
  • 517 Radio Becker Monte Carlo
  • 518 Radio Becker Europa stereo
  • 519 Radio Becker Grand Prix, USA

However, only option codes 511, 514 and 516 were available for factory installation at the time of ordering a new Pagoda:

The factory installed only Becker radios and it is highly unlikely that Becker stereo radios could be ordered from the factory - even for the latest 280SL cars - and if present in original cars then they are dealer installed.

The Becker Europa mono radios used most of the same hardware and connections (one speaker output of course).

  • Grand Prix TG - partly transistorised, Two units, Assembly with tubes and transistors, Automatic station tuning and Pushbutton station selection
  • Europa TG - partly transistorised, Two units, Assembly with tubes and transistors, Pushbutton station selection
  • Mexico TG - partly transistorised, Two units, Assembly with tubes and transistors, Automatic station tuning
  • Monte Carlo TR - fully transistorised, Single unit
  • Europa TR - fully transistorised, Two units, Pushbutton station selection
  • Mexico TR - fully transistorised, Two units, Automatic station tuning
  • Grand Prix TR - fully transistorised, Two units, Automatic station tuning and Pushbutton station selection
  • Avus TR - fully transistorised, Single unit
  • Mexico Cassette - Two units, Automatic station tuning and Stereo cassette, from 1970
  • Europa MU - fully transistorised, Single unit, AM FM, 5 pushbutton station selection
  • Europa Stereo - Two units, Pushbutton station selection, from 1970
  • Grand Prix - Single unit, from 1970
  • Avus - Single unit, from 1970

Automatic station tuning (also known as Wonderbar, perhaps a play on words with Wunderbar meaning Magic or Terrific) works by pushing the top button and the radio then scans to next strongest station.


Early and late size faceplate

Depending on the year of manufacture the Becker mono radios may not have the separate amplifier. The electronics got more compact in later years. The actual size of the separate amplifier box got smaller also. Eventually the radio tuner itself also became more compact. The face plate, escutcheon and mounting hardware remained the same. The exception is the early radio Becker TR (230 SL) which installed in a smaller dash opening with an entirely different face plate and escutcheon plate.

The Becker Grand Prix with the signal seeking feature "wonder bar" mono or stereo, always had a separate amplifier box as far as I know. The last version Becker Europa Stereo (after the W113 series) looked the same from the front but was very compact, and no longer had a separate amplifiers.

This 1972 sales information (see below) shows the Becker Mexico Cassette Stereo. This came along the year after the W113 cars, but will fit in the later "large opening" W113 dashes just fine. It also has the separate amplifier. Although it is not an original option it does have the original Becker look. Some 113 owners have upgraded to these signal seeking, "wonder bar" Becker Mexico Stereo Cassette units. Only the most familiar W113 people will detect it as non original. The outward appearance looks correct except for the door for the cassette. The list price on these Mexicos was about $800.00 thirty years ago! Since they were also used as an option in some later Mercedes sedans and 450-SL's, they can be found. Someone was lucky enough to find an excellent working one on Ebay for $40.00 in 2003. Expect to pay more or spend some time searching the net or wrecking yards.

The separate Becker Cassette player without amplifier was offered on the latest W113 cars but was less practical than the later built-in cassettes since it had to be installed by itself in the glove box or under the dash.

Becker brochure from 1972

Becker TR radios 230SL Installation Manual (German)

BOSCH Radio Interference Suppression Kit

Dealer-installed radios (mostly Blaupunkt) also required a suppression kit. These instructions show the places where the different parts were installed. For the 230SL Figures 7 and 11 are the important ones.

http://www.sl113.org/wiki/uploads/Electrical/Bosch_230SL_Suppression_Instructions.pdf

Becker GrandPrix Installation Parts

Installation Instructions (Becker Grandprix-Mono)

Here is a good installation page sent by Ed Ebel at Becker. It shows the Becker Grand Prix installation. The mounting brackets, and auxilary fuse box with its mounting is also clearly shown. The power hook up for the antenna is also shown. The Becker Europa mono radios used most of the same hardware and connections (one speaker output of course).

The connectors at the back are as follows:

  • black wire: positive 12 volt connection
  • brown wire: ground
  • two, round-pin connector: speakers - the lower pin is the ground side
  • six pin connector: test point for factory
  • spade connectors: antenna control
  • DIN Connector Layout

Radio Mounting Diagram

Fastening brackets come in different shapes and lengths and the ones on the left in the photo below may be not be useful for Becker radios. Perhaps these are for Blaupunkt or Grundig radios. Also note the correct orientation of the tightening bolt on the right.

Push buttons

Amplifier Brackets

The Becker Europa, Mexico and Grand Prix models exist as one-unit and two-unit versions, that is, with an integrated amplifier or a separate one. The separate amplifiers were mounted on the firewall inside the cabin as shown in the installation diagrams. The bracket for the Grand prix is a bit smaller than the one for the Europa model:

Stereo Installation Instructions (Becker Europa - Stereo)

Removing Radio

  • The W 113 cars have two different cut-outs for the radio in the dashboards. The rectangular dash cut-out in 230SL and early 250SL cars (until VIN 2580) is covered by a separate metal sheet that has a smaller rectangular cut-out for the radio and two round ones for the cigarette lighter and the clock.

All 280SL models lack this cover sheet and the rectangular cut-out in the dash has the standard DIN dimensions (180 mm x 55 mm) for radios.

  • To determine the method of removing the radio, look for the vertical line of the early dash near the ignition switch; under the chrome strip for the heater and vent controls. A dash with the vertical line separating two sheets of metal for the dashboard, requires partial dismantling of the dashboard to remove the radio.
  • Remove the screws holding the lower vinyl covered panel with the cabin light. Careful: the wires to the lamp are always hot - disconnect battery to be safe!
  • After removing the panel, you will see several small Phillips screws holding the chrome strip to the dash, remove them.
  • Now look at the area above the steering column and see how the strip slips into a groove for the chrome strip on the other side.
  • Remove the screws holding the Glovebox in the dash.
  • Look underneath and find the electrical connector attached to side of the blower box. Disconnect all wires then pull the Glovebox out. (Mind the door spring assembly on left side; best done with the glove box door half open. Watch out for the map light wires on the bottom left).
  • Remove the 2 knurled nuts and wire plug attached to the clock and pull out the clock.
  • Reach behind the radio and gently pull it towards the cabin and away from the tab into which the spring-loaded radio holding bracket is attached. Disconnect the ground wire and those to the cigarette lighter and then the radio with cover panel and attached amplifier box can easily be removed through the large cut-out in the dash.
  • The tuning and loudness adjust knobs are fixed to the spindles by small set screws; remove them and pull of the knobs. Then remove the slotted nuts and the front frame can be pulled away from the radio freeing the cover plate as shown in this sketch:

230SL Radio Mounting Diagram



Tuning the Antenna to The Radio


Here are factory instructions to tune the antenna to a Becker "Europa" radio and how to achieve maximum sensitivity.



Replacement of the Dial Lamp without removing the Radio




Removing Radio in a 280SL.


280SL models do not have a separate metal sheet covering the dash cut-out. This rectangular cut-out in the dash has the standard DIN dimensions (180 mm x 55 mm) for radios.

  • The face chrome surround is held by friction fit. Pull both sides of the chrome gently to remove. Remove the knobs. Some knobs have a tiny screw on the side. Loosen the screw with a small jeweler screwdriver then pull off the knobs. Gently pry the bass adjuster ring off the left knob shaft if present. Consult Figures 2 and 4 in the "Stereo Installation" instructions above.
  • Check to see if a Balance adjuster should be removed from the other shaft. The gray striped face plate will now come off. Two white metal upright “holders” fasten the radio to the dash. Remove these to allow the radio to be pulled out. Note how everything is positioned. Bag and label all parts.
  • As the radio comes out, reach in and disconnect the antenna wire, the power wire, the speaker wire, and any other wires or plugs from the back. If the center speaker is present (center speaker is often removed when kickpanel speakers are installed) remove the two screws holding the speaker wood grill.
  • The screws are between the second and third wood fins of the cover. Remove any baffle material on top of the speaker. Remove the screws holding the speaker. Might need a stubby Phillips. Remove the speaker and wire. Installation is the reverse.


Speaker removal on 230SL

Some very early 230 SL’s do not have the two Phillips screws for the wood cover. In these cars there are two small metal rods attached to the speaker grille which fit into clamps in the dash.

  • Very carefully lift the rods with a flat screw driver from the sides.

Replacement speakers may be available from MB part suppliers. Speakers that fit the space might be available form other sources. A Replica or other speaker can be used as it cannot be seen under the cover. Make sure the speaker is 4 to 5 ohms or close.

  • A mount can be fashioned to fit into the speaker space to allow other speakers to fit. Note: The speaker cover in 230SL with VIN 3009 had the two screws.

Speaker Resistance

The Becker Installation manual refers to all speakers (Lautsprecher) as being 5 Ohms. Using 4 or 5 Ohms is best but 8 Ohms will work with lower sound volume.

Re-coning a Speaker

Getting new speaker cone covering may be difficult because of the small size of the speaker.

Stereo speakers

Stereo speakers in the kickpanels were optional or standard (depending on country) for W113’s built in 1969 (1967?) and after. Blaupunkt foot panel speakers are found in some cars.

Some cars have two additional speakers installed in the rear package shelf. Some speakers and amplifiers have been “hidden” in the trunk or the glove box.

Manuals

Becker has a 4 page pamphlet with installation measurements and instructions for four speakers. Becker Radio of North America has instructions, manuals, and more about the older Becker models on its website http://www.beckerautosound.com/Classic/classics_wiring_info.htm.

Auxiliary Connector

Becker radios typically had connectors in the rear for auxiliary equipment such as a tape player and more. Some radios were used with auxiliary tape cassette players, larger amplifiers, and rear seat speakers.

Modifications:

Beckers can be modified to accept I-Pod or MP3 players, and can be converted to accept digital tuners while keeping the original look. These can be hardwired using the accessory connector on the back of the radio or by using a wireless or low power FM transmitter.

Push Buttons:

Buttons were used both to select the band (AM FM SW) and the station. Euro radios commonly had buttons marked L and U for Long and Short (Ultra) wave. North American radios had AM and FM markings. At least one Becker model was a 4 band radio: AM FM LW SW.

More: the Grand Prix was the top-of-the-line Becker in 1967. The USA model differed from the Euro version in having English button markings ("L, SW, BC, FM" vs "L, K, M, U") and a longer FM band. Also, in July, 1967, the knobs were flattened to make them comply with USA model 1968 safety regulations.

Model Variations

Some consider the “Top of the Line” Becker radio to be the Becker "Mexico" with its built in tape cassette deck. In the Becker Olympia model, the cassette player was a separate unit. Another “Top” model was the "GrandPrix", an AM/FM with automatic tuning bar. Other Becker models included the "Europa Stereo", later the Europa II”, some with tone and balance controls; and the "Europa" mono AM/FM.

The Becker Mexico has a “Q” button to switch to a tape player or other separate unit that plays through the radio.

Some 230SL's were originally fitted with Europa TG radios.

Grand Prix Stereo had a separate cassette player and amplifier.

Stereo cassette models were available from as early as 1967.

Modern Upgrade with original look

Can leave the original period Becker in the dashboard slot and install a modern stereo unit under the driver's seat operated with an infrared remote control. Modern speakers can be hidden if placed flush below the rear wooden flat panel sections. A CD changer can go into the trunk, or

Use a DIN-plug adaptor that connects to the back of the Becker or Blaupunkt. Run the wire to the glovebox to hook up a digital handheld unit. For the DIN-plug adaptor specify stereo or mono radio.

Also see DIN Connector Layout and iPod interfaces.

Knobs

The knobs on early radios were small with indented centers; later style knobs were larger and flatter. The early style (fintail) radio knobs do not fit the studs of the later radios.

The Tone Control levers were chrome on early radios and black plastic later.

Fuse


Fuse box

On most 280SL’s the fuse for the radio was in a small box with a bakelite cover attached to the inside top of the passenger fender next to the voltage regulator. The box also had the fuse the motorized antenna. Not all models had the radio fuses at the right fender position.

In early 230SL cars the radio fuse box was powered from the B+ terminal on the back of the alternator (the 10 mm nut). Can use the #3 fuse to have the radio switch on with the ignition. There is no accessory position on the ignition switch on SL's made before 1968.

In late 230SL and subsequent models there is already a factory installed red/green supply wire taped back in the harness:

On cars 68 model and later, radio should have power when the ignition switch is in the 1 or 2 position. Power comes from the terminal marked "R" on the ignition switch.

Corrosion

From time to time, remove the screws holding the radio wires to the radio fuse box and clean the connections. Because of the location of the box, corrosion is possible.

Installation Space

The dash opening for the radio changed size after the 230 SL and early 250SL. The early cars had a narrower hole for the radio. Some of the later Becker radios of the period were not backward compatible with the older cars.

For 230 and early 250 cars: to retrofit a correct radio (1963-1967) the center sheet metal piece of the dashboard must be replaced. The older radios fit into a 4.5 cm high radio slot while the later radios used a wider 5.5 cm high slot.

Photos of some Becker Radios of the 1960's and 1970's


Becker Olympia with separate cassette player

Becker Grand Prix



Becker Europe TR

Typical back of Becker radio



Becker Europa II Stereo

Becker Europa



Becker Mexico with integrated Cassette player

Becker Grand Prix Stereo



Becker Europa for USA


Blaupunkt order form and parts list for 230SL


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