I bought a Becker 1480 from ebay "as is"
Ofcouse it didnt work.
When I pushed on the "ON" button you could here the relay clanking, but nothing would happen. If you kept the "ON" button pushed in, The relay would keep clanking.
Then I put an logic analyzer on the I2C bus, and some stuff was happening lucky.
So the CPU/EPROM programming is still there.
When you put power on the radio, the CPU resets the LCD screen to empty.
A Value is read from a I2C eeprom (AT24C01) Then 4 values are readed from the eeprom, and the CPU kept doing that in a loop.
Pushing the "ON" button there the relay is clanking but nothing else happening on the I2C.
There my knowledge is ending.
But I readied a lot of problems come from old electrolyte capacitors. So i changed the main cap (3300uF 16v) from a other (old)Becker.
Tada!! the radio is asking for the code. But after the code the radio fails again.
So i bough a new cap at a local shop, and the radio lives a little longer, but after 30 sec the radio shutsdown again.
So i have made an order for all the caps in the radio to replace them.
Ofcouse it didnt work.
When I pushed on the "ON" button you could here the relay clanking, but nothing would happen. If you kept the "ON" button pushed in, The relay would keep clanking.
Then I put an logic analyzer on the I2C bus, and some stuff was happening lucky.
So the CPU/EPROM programming is still there.
When you put power on the radio, the CPU resets the LCD screen to empty.
A Value is read from a I2C eeprom (AT24C01) Then 4 values are readed from the eeprom, and the CPU kept doing that in a loop.
Pushing the "ON" button there the relay is clanking but nothing else happening on the I2C.
There my knowledge is ending.
But I readied a lot of problems come from old electrolyte capacitors. So i changed the main cap (3300uF 16v) from a other (old)Becker.
Tada!! the radio is asking for the code. But after the code the radio fails again.
So i bough a new cap at a local shop, and the radio lives a little longer, but after 30 sec the radio shutsdown again.
So i have made an order for all the caps in the radio to replace them.
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I replaced almost all the elec. caps.
But is still a no go.
The radio comes to live, and in is in the wait state.(on the lcd) because of wrong code
Then the "wait" disappears from the lcd after 10-20 sec and the radio starts doing crazy.
I get static from the speakers, is going off/on the relay is clicking.
Any ideas?
But is still a no go.
The radio comes to live, and in is in the wait state.(on the lcd) because of wrong code
Then the "wait" disappears from the lcd after 10-20 sec and the radio starts doing crazy.
I get static from the speakers, is going off/on the relay is clicking.
Any ideas?
Have you tried posting on a Mercedes forum? Some of these symptoms may be commonly known and someone may have a solution.
really dificult units to repaiar as they keep the "hard way" germany enginering to their phillosophy....find someone that has experience with these units ...might be something very simple like dry joint or something....are you sure you connect the 12v to the correct points like ACC and BACK UP supply ....double check them....as i said germany philosophy....!!!
@mixals spl: everything is hook up good, using the becker connectors.
Well i got the radio somewhat working.
The radio accepts the code, if it stays alive, the you can tune to a radio station.
But the quality of the reception is very poorly. But its a matter of time and the radio fails.
The relay (that switch the 12v to the rest) is getting its own live and start to clicking.
Often the radio doesn't turn on. And sometime the relay begins its own live. when the power is hook up.
If i remove the CPU of the radio, nothing will happen, the radio stays dead.
Well i got the radio somewhat working.
The radio accepts the code, if it stays alive, the you can tune to a radio station.
But the quality of the reception is very poorly. But its a matter of time and the radio fails.
The relay (that switch the 12v to the rest) is getting its own live and start to clicking.
Often the radio doesn't turn on. And sometime the relay begins its own live. when the power is hook up.
If i remove the CPU of the radio, nothing will happen, the radio stays dead.
If I remember correctly, 780, 754 and 1480 are not different by much.
You could be having issues with the clock because this would messup the timing and the addressing.
I would probably start with disconnecting devices from SDA/SCL/ENA lanes, one at the time, and see where it becomes stable.
Heat could play some role, freezing the IIC devices can be another way.
Of course, you MUST confirm that supply volts are good.
If you do not have the diagramme, datasheet for individual IC's will tell you their supply range
You could be having issues with the clock because this would messup the timing and the addressing.
I would probably start with disconnecting devices from SDA/SCL/ENA lanes, one at the time, and see where it becomes stable.
Heat could play some role, freezing the IIC devices can be another way.
Of course, you MUST confirm that supply volts are good.
If you do not have the diagramme, datasheet for individual IC's will tell you their supply range
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