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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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Discussion Starter #1 (Edited)
I had an extra Becker 754 radio (previously from a 300E) that I wanted to install in my '89 560 R107. As many know, the 754 model utilizes a lithium battery (cutting edge technology at the time) and when the radio is removed from a power source (e.g., stolen and or pulled out of the car) the lithium battery will eventually go dead, putting the radio into a locked mode where once powered up again, the display will show dashes. Unfortunately, these radios do not have a security code like many of the Becker units. The Becker 754 requires a "reset" by the dealer. I wanted to provide what I did to bring this radio back to life, as there is little information on this subject.

1. I took the radio to a local electronic repair shop and we replaced the lithium ion batter (3.6 volts / half AA size) and soldered the new battery to the board. (This cost $20)

2. I then approached a contact at my local Mercedes dealer (Hendrick Mercedes - Charlotte, NC) and asked if they had any "old timers" that may remember how to reset one of these radios. Luckily, one mechanic knew how to do this, and still had the tool to "reset" the radio. He said he would do this at no charge!

3. Remove the face plate of the radio (easiest when removed from the car). With face plate removed, install the radio in the car / connect all wiring to the rear of the radio.

4. With the ignition off, insert the reset tool (see photos) into the face (where to connect should be obvious). Hold down green button on the reset tool, then turn on the ignition to power the radio. Release the green button. Remove the reset tool and install the face plate back on the radio. The radio should now work and it should be "unlocked" / eliminate the dashes that previously appeared on the screen. The instructions for this process are also located inside the case that houses the dealer's reset tool.

Hopefully this helps others who may want to restore / revive a Becker 754 radio. Also, many thanks to the folks at Hendrick Mercedes in Charlotte, NC.
 

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1983 380SL, ivory/dk brown, 46k miles, dual roller timing chain. 1986 560SL, red/white, 190K mile.
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7,002 Posts
Great information - I like the photos you posted.
Never seen that tool.
I have a 754 radio that does not work and that tool
just might revive it. The only problem is getting access to that tool.
 

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2015 ML250 Bluetec and 1987 560SL
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Well, for you, Carl, all you need to do is run over to Charlotte. The rest of us might have a bit harder time.
 
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1983 380 SL
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Other than for reasons of nostalgia, why bother reviving an old radio when new radios are far superior and cheaper?
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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101 Posts
Discussion Starter #5
Agreed that new radios are much better than the old technology, however for some, we prefer that the aesthetics remain original in these cars - for me, that is the sole reason.
 

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1983 380 SL
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Agreed that new radios are much better than the old technology, however for some, we prefer that the aesthetics remain original in these cars - for me, that is the sole reason.
Agreed. In fact I still have my old Becker... but it's in a Benzi-Box.

Sidebar with apologies:

After loosing a few radios to the poor misunderstood youth of the 80's, I had a Benzi-Box installed. The problem of stolen radios became so pervasive that some enterprising folks started marketing stickers for the Mercedes owners windows with the words "No Radio", just to stop the thieves before doing damage. I never locked my 107 as to avoid the costly damage done to rag top... or when the hardtop was on... glass, but that didn't stop the drug crazed guy that stole my radio from first slitting my top.
 

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86 560SL
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1,243 Posts
I had my radio reconditioned primarily to deactivate the theft deterrent system. I thought about getting an aftermarket unit but just didn’t care for the looks of the new radios.
 

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1983 380SL, ivory/dk brown, 46k miles, dual roller timing chain. 1986 560SL, red/white, 190K mile.
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7,002 Posts
...
After loosing a few radios to the poor misunderstood youth of the 80's, I had a Benzi-Box installed. The problem of stolen radios became so pervasive that some enterprising folks started marketing stickers for the Mercedes owners windows with the words "No Radio", just to stop the thieves before doing damage. I never locked my 107 as to avoid the costly damage done to rag top... or when the hardtop was on... glass, but that didn't stop the drug crazed guy that stole my radio from first slitting my top.
I do remember in the 1970s and 1980s when New York City was sleazy POS for a city seeing fancy cars with those signs "No Radio".
I remember thinking it would be a cold day in Hell before I would drive my new 380SL or any car for that matter in downtown NYC.
 

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1973 450SL, 1999 c230
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928 Posts
I spent a weekend installing a 'BETTER' quality radio in a poxy Renault back in the 80's. One of the local scum must have seen me working on it because the next day it was gone. They broke the rear quarter-light which really pissed me off because the doors were not locked.
 

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1983 380 SL
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3,093 Posts
I spent a weekend installing a 'BETTER' quality radio in a poxy Renault back in the 80's. One of the local scum must have seen me working on it because the next day it was gone. They broke the rear quarter-light which really pissed me off because the doors were not locked.
I suspect you're not a fan of income redistribution. :smile
 

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Outstanding Contributor , Bob's Your Uncle!
-----'83 280 SL----- 5 speed....The PIG
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1973 450SL, 1999 c230
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I am more belligerent than I was back then. I now believe an Eye for an Eye... Translated as : You touch my Radio and I get a new pair of balls to dangle from my mirror.
 

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1983 380 SL
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I am more belligerent than I was back then. I now believe an Eye for an Eye... Translated as : You touch my Radio and I get a new pair of balls to dangle from my mirror.
You may be more right than you think. I wasn't going to tell this part of the story but now that you mention being more belligerent now than you were then... here goes. I caught the kid that stole my radio (it was the second radio, I already had the original radio stolen). I took pity on him (hey I was only about 35 myself at the time) and told him to hand me the radio and I'd let him leave. He handed me the radio... wires hanging out an all... and walked away. I don't know if I would be as forgiving today.
 

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1972 220 D, 1974 450SL, 1995 E300D 2002 S430, 1976 300D, 1986 SDL, 1982 SD
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Jyuma, initial read through came out --

"...told him to hand me the radio and I'd let him live."

Just goes to show how I feel on the topic. I had Becker rebuild my Europa II, and would kill the bastard that screws it up.
 

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1974 450SL (US), 2005 SLK200 (UK)
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My guess is that at power on the microprocessor looks for a high or low voltage on a specific pin and if it sees it then it unlocks. That would make the innards of the tool trivial - press the green button and it connects the relevant pin to postive or GND. All pins are included on the tool just so the user can't screw up how to plug it in.

Would be nice if the schematics of the radio could be obtained from somewhere.

Perhaps Becker can provide details of the tool? A mechanic probably doesn't know if instructions were included with it - just follow the instructions and job done.

"Last microprocessor in the UK"... I wonder if that line is used on all customers? ;) Sorry, I am getting more cynical with age...

Andy
 
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I have the schematics somewhere, I can email them if needed.

I also assumed a similar process, although I couldn't unlock the radio by trying various resets like that. If there are any electricians present who might have ideas, am happy to try.

Becker didn't want to engage me in conversation about the tool, my guess is that it's their proprietary info and helps them make a living, so fair enough.

"last processor" - well, I considered it, but I actually got the sense he wanted to keep it rather than sell it to me.
 
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