[ICOM] Delayed Start-up Circuit

[Sheldon Daitch]

QST, June 2003, published Mike Bryce's article on THE PROTECTOR,
a time delay and voltage monitoring unit, for 12VDC systems.

A complete kit of parts was available, at one time, from the author,
and you might contact him at this email address:

  prosolar at sssnet.com

I bought one of the kits, assembled it and am happy with the way the
unit works.

73
Sheldon
WA4MZZ

"Davies, Doug A FOR:EX" wrote:

> This question is a result of the recent problem I had with my IC-02AT.
> Although I can't confirm it, my suspicion is that the cause of the squeal
> problem with the handheld may be attributable to how I had it hooked up in
> the vehicle.  I had the rig powered via the external DC input jack on the
> top.  This was plugged into one of the power points.  These are not "hot"
> unless the vehicle is either running or the key is in the accessory
> position.  The result is, when the car is fired up, the radio goes on for an
> instant then as the engine is turning over and drawing power the radio goes
> off due to lack of sufficient voltage.  Once the engine is running the radio
> then goes back on.  I am thinking that this on-off-on cycle is not good for
> the rig.
>
> I have a good idea of how to correct this but lack the technical knowledge
> to pull it off.  I would like to build a circuit that would include a
> delayed start-up function.  I want it to only send the 13.8 volts to the
> radio after say, five seconds after the key is turned on.  This will
> eliminate the cyclic thing and only allow the radio to go on once the
> voltage has stabilized.
>
> I would really appreciate it if those in the know about such things could
> provide me with some ideas on how to construct such a circuit.
>