G-5500 Troubleshooting

John Meeks

1 May 2010 1 May '10

9:22 p.m.

I need some help diagnosing my non operative g-5500 azimuth rotator. After a few no copy passes, I noticed the azimuth meter was not moving. Disconnecting my G232 interface, manual operation with the 5500 az switches produced no movement of either the meter or the antenna array. Elevation works fine.

Swapping the cable connections on the back of the controller allowed the azimuth switches to operate the elevation rotator. I think this tells me the controller box is probably ok. The ele switches did not operate the az motor. So, either cable, connector or motor? Returned connectors to their original positions.

Measuring impedance on the cables in the shack using pin 6 as the common gave me 4.6 ohms on both pins 4 and 5 on the elevation cable. The azimuth cable gave me 4.5 ohms from 6 to 5 and 6 to 4 was OPEN. So... could be the azimuth cable or connector. Braving high winds I climbed my tall roof mounted tripod and swapped cables from az to el and el to az. The az cable was now controlling the elevation motor no problem. Azimuth still non-operational. So have I eliminated all but the azimuth motor? Are there any other possibilities to consider before I dismantle the whole rooftop array?

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

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i8cvs

2 May 2 May

2:27 a.m.

New subject: [amsat-bb] Re: G-5500 Troubleshooting

----- Original Message ----- From: "John Meeks" [email protected] To: [email protected] 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

John Meeks

9:17 p.m.

New subject: [amsat-bb] Re: G-5500 Troubleshooting

i8cvs wrote:

...

----- Original Message ----- From: "John Meeks" [email protected] To: [email protected] 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

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

i8cvs

10:30 p.m.

New subject: [amsat-bb] Re: G-5500 Troubleshooting

----- Original Message ----- From: John Meeks To: i8cvs Cc: AMSAT-BB Sent: Sunday, May 02, 2010 11:17 PM Subject: Re: [amsat-bb] G-5500 Troubleshooting

i8cvs wrote: ----- Original Message ----- From: "John Meeks" [email protected] To: [email protected] 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.

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

John Meeks

3 May 3 May

12:55 a.m.

New subject: [amsat-bb] Re: G-5500 Troubleshooting

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:[email protected]>
*To:* i8cvs <mailto:[email protected]>
*Cc:* AMSAT-BB <mailto:[email protected]>
*Sent:* Sunday, May 02, 2010 11:17 PM
*Subject:* Re: [amsat-bb] G-5500 Troubleshooting

i8cvs wrote:

...

----- Original Message ----- 
From: "John Meeks" <[email protected]>
To: <[email protected]>
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

i8cvs

1:55 a.m.

New subject: [amsat-bb] Re: G-5500 Troubleshooting

----- Original Message ----- From: John Meeks To: i8cvs Cc: AMSAT-BB Sent: Monday, May 03, 2010 2:55 AM Subject: Re: [amsat-bb] G-5500 Troubleshooting

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

Hi John, KC8ZFN

Now you have to find out why the trace over the PCB was severed burned out. The fuse F-1 in the control box is undamaged because it is a 2 A delayed type at 220 volt.

If you got a net short circuit as seen by the 24 volt AC secondary winding of the power transformer T-1 probably the current preferred to burn out the trace instead of the fuse.

Check if the value of the ohmic resistance of both motor winding are the same value and check also if the electrolitic AC capacitor C 34 is shorted out or not.

Have fun

73" de

i8CVS Domenico

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