[amsat-bb] Re: Help with Yaesu g5500

i8cvs domenico.i8cvs at tin.it
Mon Nov 23 02:12:00 PST 2009

----- Original Message -----
From: "Michael J. Wolthuis" <wolthui3 at msu.edu>
To: "Elan Portnoy" <elanportnoy at yahoo.com>
Cc: <amsat-bb at amsat.org>
Sent: Monday, November 23, 2009 2:07 AM
Subject: [amsat-bb] Re: Help with Yaesu g5500

> Not the switch unfortunately.  The same problem occurs when controlled
> by computer from Uni_trac 2000.  Work about 25% of the time.
> Mike
> kb8zgl

Hi Mike, KB8ZGL

Connect an AC voltmeter between A4 and A5 on rear of control box and
check if there is 24 volt AC when the rotator sticks.

If you have 24 volts when the rotator sticks connect an amperometer in
series with A4 or with A5 and check if the AC current flows as soon
the rotator sticks.

If the current flows when the rotator sticks probably the internal AC 100 uF
capacitor is defective or you have a mechanical problem inside the reduction
gear or into the ball bearing holder of your rotator

If you have a 100 uF AC capacitor in the junk box connect it across A4 and
A5 and try again to see the effect.

If you don't have an AC capacitor you can buit it by your self using two
electrolitic capacitors each 200 uF 250 volt DC and two diode 1N4007
or equivalent connected as per the following schematic diagram:

                         -   +              +   -
               |--------) |------|------| (--------|
   A4-----|                      |                       |-------A5
                     1N4007       1N4007

If the rotator sticks and if the AC current don't flow you probably
have e limit switch SW6 or SW7 defective "poor contact and high
resistivity" between contacts.

Disconnect A4 and A5 from control box and using an ohm-meter
check the continuity of the motor windings

If one winding of the motor has a fail contact then your ohm-meter
will jump measuring the capacity of the AC capacitor.

This is what I would do easy and fast in your situation.

Have fun

73" de

i8CVS Domenico

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