MB-Sub X1-VB focusable back-up - pictures (heavy)


Jan 21, 2010
Ok, thx! Its great to have had a keen eye looking at this :).

If I understand correct the resistor might help inbetween the control pin and the minus.
Indeed the housing is plus with this setup.
Tried to understand Meder's white paper on Reed's, but couldn't make out if the AMC-driver was resistive or capacitive?

I will have some more attempts soon.
And have to look for the Meder reed... it is not where I left it. Probably stuck in the cat's fur when he walked away after its nap on top of it...
Have more small reeds at hand, but the original was picked to suit best. Still have the type number.
Thx so far, I will update with news.


Flashlight Enthusiast
Jan 27, 2010
Connecticut, USA
The particular reed probably isn't very important, as long as it fits on the board and works with the magnet.

The driver should look both resistive and capacitive. But they may have left off the capacitors to reduce cost. Does it have one or two brown or tan colored blocks with metal ends? Those would be the recommended bypass capacitors. They should be small enough to have no detrimental effect on the reed. And the resistive component is definitely not going to hurt the reed.

lucca brassi

Feb 1, 2008
Kocevje , Slovenia, Europe
Do you have maybe short circuit through LED PCB - star - ''leakage current'' ? Caused maybe with csrews ?

Sorry I don't have clear sequence of events , you have done , that's why I don't want to suggest something wrong .

Also I have had not work with DX circuits like AMC series ( whith that I mean that I don't know how Cu trace is routed and where are possible weak points to do short circuit )

In my case have used first SST-90 with AMPERE ! & PWM ( for magnetic switch at 30% ) and then reduced to SST-50 with AMPERE ! lowered to 5A & PWM ( for magnetic switch at 30% ) because lens is to small after

that light is solid.

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