Ok Here's the reason for the apparent open winding in the AZ rotator motor. http://picasaweb.google.com/vanagon/YaesuG5500AntennaRotator The burned trace is severed, thus the open readings seen between Azimuth 6 and 4. I'm pretty sure there were no snags or obstructions that could have stopped rotation while powered. I'm really lucky though, the fuse in the control box is undamaged ;-)
Thanks to Dom i8cvs for all the troubleshooting tips below. I will try my hand at rebuilding this motor and use these tips to verify the work. Thanks as always for the great information. John Meeks KC8ZFN i8cvs wrote: > > ----- Original Message ----- > *From:* John Meeks <mailto:jm...@gaslightmedia.com> > *To:* i8cvs <mailto:domenico.i8...@tin.it> > *Cc:* AMSAT-BB <mailto:amsat-bb@amsat.org> > *Sent:* Sunday, May 02, 2010 11:17 PM > *Subject:* Re: [amsat-bb] G-5500 Troubleshooting > > i8cvs wrote: >> ----- Original Message ----- >> From: "John Meeks" <jm...@gaslightmedia.com> >> To: <amsat-bb@amsat.org> >> Sent: Saturday, May 01, 2010 11:22 PM >> Subject: [amsat-bb] G-5500 Troubleshooting >> >> >>> One more thing... Given that the cable tested OK, what does the open >>> reading from 6 to 4 suggest? My reading of the schematic diagram is >>> sketchy at best. >>> >>> Any and all help will be greatly appreciated. >>> >>> John Meeks >>> KC8ZFN >>> >> >> Hi John, KC8ZFN >> >> After the carefull troubleshooting you did and described the actual open >> reading from 6 to 4 in the az. motor suggests two possible autcomes. >> >> 1 ) The limit switch SW6 inside the rotator is defective and is an open >> circuit >> >> 2) The winding of the motor connected to limit switch SW6 is open >> so that the motor cannot run nor left and nor right >> >> Since 6 and 4 are an open circuit the electrolitic unpolarized capacitor >> inside the motor appears to be not involved in this type of problem. >> >> Please let me know just for curiosity the result of your investigation >> but I believe that you have to open the azimuth rotator. >> >> Best 73" de >> >> i8CVS Domenico >> >> > Thanks for confirming my conclusions so far, Dom. > > I've Got the Az rotator on the bench. It looks and smells new. The > limit switches present a closed circuit until the swtich is > activated when they open as expected. > > Looking for continuity between the pin corresponding to to A6 > (black wire) and one of the limit switches (red wires) shows 3.7 > ohms, and to the other switch (green wires) is an open circuit. > I'm thinking this should be continuous also. If this is the case, > what are my options? Has anyone had success repairing this motor? > > Thanks for the help. > John Meeks > KC8ZFN > > > Hi John, KC8ZFN > > Disconnect momentarely the electrolitic capacitor C34 > > If the rotator is into an intermediate angular position the limit > switches SW6 and SW7 are not activated and so they are in a > normally close condition and must show a close circuit or zero ohm > > Looking for continuity between the common of the motor winding A6 > and directly to each end of both motor windings you must measure > the same continuity with a resistance of 3.6 ohm > > In addition you must measure the continuity and 3.6 ohm between A6 > and both at the input and at the output of each limit switch SW6 > and SW7 > > Measuring the resistance across each limit switch when the rotor > is into an intermediate angular position you must measure zero ohm > if SW6 and SW7 are OK since they are normally closed. > > If the limit switches SW6 and SW7 are OK then the motor winding > showing an open circuit must be rewired because of a > possible interruption somewere into the winding. > > Since you have the rotor over the working banch it should non be > difficult to locate the interruption. > > If one motor windind must be rewired it is possible to rewind it > by hand because there are not a great numbar of turns for 24 volt AC > > Please let me know. > > 73" de > > i8CVS Domenico > > > > _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
