[amsat-bb] Re: Playing With Lightning

H. Vordenbaum tower2 at stx.rr.com
Sun Mar 14 06:41:43 PDT 2010

The voltage regulator in my KR-5400A was damaged by a lightning strike and 
had to be replaced........
73, Harvey K5HV

----- Original Message ----- 
From: "i8cvs" <domenico.i8cvs at tin.it>
To: "Joel Black" <jbblack68 at gmail.com>
Cc: "'AMSAT'" <amsat-bb at amsat.org>
Sent: Saturday, March 13, 2010 19:20 PM
Subject: [amsat-bb] Re: Playing With Lightning

> ----- Original Message -----
> From: "Joel Black" <jbblack68 at gmail.com>
> Cc: "'AMSAT'" <amsat-bb at amsat.org>
> Sent: Saturday, March 13, 2010 10:44 PM
> Subject: [amsat-bb] Playing With Lightning
>> I certainly appreciate all the replies and the encouragement.
>> If any of you with a G-5400 controller would check something out, I'd
>> appreciate it.  When I move up or right, there is a momentary deflection
>> in the opposite direction.  Then, when I release the button, it jumps
>> ahead a bit by just a few degrees.  If I move down or left, there is no
>> immediate deflection, but when I release the button, it deflects in the
>> opposite direction.  I just don't remember mine acting that way before
>> the strike.
>> Thanks,
>> Joel, W4JBB
> Hi Joel, W4JBB
> Trouble-shooting for your G-5400
> I suggest you to momentarily disconnect the wires A1-A2-A3 going from
> the rear of the control box up to the rotator.
> Connect  temporarely for test a 500 ohm wire wound potentiometer to
> terminals A1-A2-A3 of the control box taking into account that A2 is the
> wiper of the potentiometer.
> Power supply the control box and rotate very slowly by hand the shaft of
> the potentiometer.
> If the pointer of the azimut instrument follows accordingly your rotation
> by hand than there is no damage into the control box.
> Repeate the same procedure for the wires E1-E2-E3 to test the elevation
> remembering that E2 is the wiper of the potentiometer.
> If the pointer of the elevation instrument follows accordingly your by 
> hand
> rotation of the potentiometer then there is no damage into the control 
> box.
> If  the deflection of the instruments is still like you describes probably
> the integrated circuits C3 and C4 into the control box where damaged by
> the strike.
> Reconnect the original wires between the rotator and the control box and
> using a high impedance DC voltmeter measure the voltage between A2-A3
> and E2-E3
> While rotating the antennas left and righ and up and down  observe if the
> voltage follows  smootly the above rotation.
> If the voltage jumps there is probably a damage into the potentiometer
> wipers inside the rotator
> Check if the voltage between A1- A3 and between E1-E3 is about 6 volts.
> The voltage must remain constant at about 6 volts rotating the antennas
> othervise the voltage regulator Q2 was damaged by the strike.
> Using the above trouble-shooting you can establish if the problem is 
> located
> into the rotator or into the  controlbox or along the wires connecting 
> both.
> Have fun !
> Best 73" de
> i8CVS Domenico
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