3 May
2010
3 May
'10
2:55 a.m.
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:jmeek@gaslightmedia.com> *To:* i8cvs <mailto:domenico.i8cvs@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" <jmeek@gaslightmedia.com> To: <amsat-bb@amsat.org> Sent: Saturday, May 01, 2010 11:22 PM Subject: [amsat-bb] G-5500 TroubleshootingOne 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 KC8ZFNHi 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 DomenicoThanks 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