"Miracle switch" failures

[John Ferrell]

If I understand the failure conditions, the electronic switch was paralleled
with a mechanical switch.
That is not something that would be considered a 'normal' configuration for
the electronic switch.
I refrain from using these devices because I have never had a switch problem
with a Futaba switch.
Most electronic power switching devices that I am aware of are MOSFET
technology.
These devices switch many amps with great reliability, but are extremely
vulnerable to voltage spikes.
The inputs and outputs are protected by internal diodes from these spikes.
I have been unable to puzzle out if there is an unprotected input-output
junction.
Here is a possible scenario:
    The mechanical switch is turned off generating a spike that damages the
elecronic switch in a failure
    mode that drags down the receiver voltage feed.
My personal conclusion is that either switch will work as advertised, but
when used in tandem it is
not a matter of if it will fail but when it will fail.

John Ferrell
6241 Phillippi Rd
Julian NC 27283
Phone: (336)685-9606
Dixie Competition Products
NSRCA 479 AMA 4190  W8CCW
"My Competition is Not My Enemy"



----- Original Message -----
From: <s.vannostrand at kodak.com>
To: <discussion at nsrca.org>
Sent: Monday, March 24, 2003 1:16 PM
Subject: "Miracle switch" failures


> I know there are some vendors and users of those voltage regulators with
> the built in switch.  One mfg calls it the miracle switch.  I have one,
> hooked it up, am using it with no problems so far, but I may be just
lucky.
> Is there a right/wrong way to hook up the connectors?  I have a radio
south
> one and there are two male connectors (one for the receiver, and one for
> recharging), and one female (for the battery input).  The system works
with
> either male plugged into the receiver.  Based on Wayne's sad story below
> I'm wondering if maybe only one should be connected to the receiver in
> order to maintain voltage when the switch fails.
>
> Anyone know if there is a sure way to tell if you have it hooked up
> correctly?
>
>
> Wayne writes, " I am/was using a MCI Miracle switch that is a regulator
and
> has fail safe if the mechanical switch contacts fail the switch stays on
> all the time.   I tested the battery and it checked at 6.5v.  I checked
> through the charge port and 6.5v.  But when I checked it through the
> connector to the receiver it only registered 4.25v  just below the
> receivers voltage threshold. "
>
> --Lance
>
>
>
>
> =====================================
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>

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