Re: [DML] Re: Problem with Lockzilla

[Martin Gutkowski <webmaster@xxxx>]

Elvis,

I have done some extensive research on these modules which is all documented in the DMC
news tech article. I don't think you've had to troubleshoot a malfunctioning unit before,
hence why you don't see any reason to add protection diodes, replace the capacitors or
transistors.

You're right though (as is Knut), I didn't spend as long as I should reading the diagram
(which should be oh-so-familiar by now!) before posting last.

I am very well aware that switching a relay off slowly is very bad - and have said this
on several occasions before. It causes arcing and pitting of the contact surfaces.
However, if you use sealed relays which contain an inert gas, you bypass this problem.
The OEM module is a crap design, but by replacing and adding various components, I'm
happy mine's robust enough to trust with a remote central locking system which I've
fitted and has been working for 8 months now.

Martin
#1458 & #4426

Elvis Nocita wrote:

> Like I said some days ago, the Door Lock Module drains 13mA during standby.
> And that's not zero ! You don't even need to measure it, just take a look at
> the schematic and
> use the formula invented by Mr. Ohm.
> I modified about 10 modules, and never had to replace the caps so far !
> The relays need to be replaced because the contacts are always worn.
> That's due to the fact, that the power for the relays only comes from the
> caps.
> While they are discharged (relays close contact) the voltage of the caps
> drops
> and also the current in the coil. The force of the relay depends of I*n
> (I=current, N=number of windings). Now when the force drops slowly (and
> that's how the module is designed to do), the contacts burn a little bit
> everytime they have to open the circuit. In some cases the contacts may
> stick together like being welded. That's exactly when you need new selenoids
> afterwards. I talked to a friend who works for Marquardt (they make any kind
> of switches, also the electronic keys for Mercedes) and he said reducing the
> force slowly is the worst thing you can do for a contact.
>
> Normaly these modules should all be replaced but this wouldn't be original
> anymore. Instead replace the relays and the system will be ok for some more
> years.
>
> Elvis & 6548