----- Original Message ----- From: Dave Webb KB1PVH To: i8cvs Sent: Tuesday, February 08, 2011 3:36 AM Subject: Re: [amsat-bb] G5400 elevation issue
Domenico,
The highest voltage that I can get at full 180° flip is 2.78 volts with voltage adjustment pot on rear of controller box.
Dave - KB1PVH
Hi Dave, KB1PVH
Make the following troubleshooting :
Measure please the DC voltage across E2 and E1 with the antennas at full 180° flip.Since the display on the control box reads correct elevation you must read about 5 volt DC.
By the way since as measured between pin 1 and 8 of the external control DIN connector and with the voltage adjustment of pot VR4 you can get only 2.78 volt at full 180° flip it means that there is someting damaged across the operational amplifier Q4 4558 1/2
Since the pot VR4 is 10 k and there is a 4.7 k fixed resistor in series of it if you measure the voltage across VR4 you should get about 3.3 volt DC
By the way measuring the voltage between the wiper of VR4 and the ground you should get a voltage change between 5 volt to 3.3 volt while rotating VR4 fully 270° back and forth
If this is the case than the operational amplifier Q4 4558 1/2 do not correctly amplify the DC input signal applied to Q4 input pin 3 from the wiper of VR4
Measure the DC voltage between output pin 1 an ground of Q4 and rotating VR4 by 270° back and forth you should get and amplified voltage greater than 5 volt DC and if not check diodes D22-D23-D24-D25 and all components connected around Q4
If all components diodes-resistors and capacitors are nominal than it is possible that Q4 has lost amplification.
In this case change the 47 k feedback resistor R39 with a 100 k resistor and the amplification will increase at a point that flipping the antenna at full 180° the voltage across pin 1 and 8 of the DIN external connector will rise up to 5 volt DC or more.
Have fun
73" de
i8CVS Domenico
On Feb 7, 2011 7:46 PM, "i8cvs" [email protected] wrote:
----- Original Message ----- From: "Dave Webb KB1PVH" [email protected] To: "AMSAT -BB" [email protected] Sent: Monday, February 07, 2011 5:16 PM Subject: [amsat-bb] G5400 elevation issue
The display on the control box reads correct elevation, but on my digital display on the Easy Rotor Controller shows erratic elevation position. I have recalibrated it several times with no success. It won't read any elevation until it is around 20° give or take. It also seems to have become worse since our really cold temps set in. My best guess is the pot in the rotor, but not sure where to start in the process.
Thanks in advance
Dave - KB1PVH
Hello
I have a G-5500 and I cannot move the azimuth controls, I also have the LVB tracker and when I try to manually change CW or CCW on the main unit or LVB it does not respond, the elevation is fine. I would appreciate any ideas on where I should begin to determine which part has failed, thank you.
73's Pete WB2OQQ www.massapequanyweather.com
Pete,
Various things to try. .
Check the connections at the screw connectors on the back of the control unit. Sometimes they work loose.
If at all possible, swap the connectors at the rotators. The circuitry is identical in the G-5500. If the azimuth still doesn't move when you activate the elevation controls, it is a rotator problem.
If it does move after switching the connectors, the problem is in the azimuth wiring, or the control box. Disconnect wires 4,5,6 and measure the DC continuity to the rotator. You should see a couple of ohms 4-6 and 5-6, and about twice that 4-5. If the continuity is bad, it is a broken wire or connector. It is unlikely, but possible, that both limit switches have failed. If the continuity checks good, then look at the voltage from the control box. Make certain you see AC voltage between 4-6 and 5-6 when you close the appropriate switch.
If everything checks out, it is probably the phase shift capacitor inside the motor. Let us know what you find.
Alan WA4SCA
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peter Portanova Sent: Tuesday, July 26, 2011 4:27 PM To: [email protected] Subject: [amsat-bb] Re: G5500 Azimuth issue
Hello
I have a G-5500 and I cannot move the azimuth controls, I also have the LVB tracker and when I try to manually change CW or CCW on the main unit or LVB it does not respond, the elevation is fine. I would appreciate any ideas on where I should begin to determine which part has failed, thank you.
73's Pete WB2OQQ www.massapequanyweather.com
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Thanks to all for the refresher on the 5500 repair. I replaced the 17806P (which I think has a 6v output) with a 7805. This fixed the problem. I had to recalibrate as my max readings in the SatPC32 rotor calibration routine dropped because of the assumed lower output voltage of the 7805 regulator. I could only get a max azimuth reading of 206, somewhat less than the 255 needed, but this seems to work ok.
Does anyone know a source for a replacement bulb in the display? Both my bulbs are burned out and I would like to replace them with something I can obtain locally. Thanks again for all the help...
73 Jeff kb2m
Jeff,
I replaced the meter bulbs in my G-5400B once, only to be disappointed that they burned out relatively soon.
I have now put two white LEDs above each meter. From memory, I put two LEDs and a current limiting resistor (about 1 Kohm) in series and connected it to the 12 volts for the bulbs, one set above each meter.
I sent you a picture by separate e-mail.
73, Steve N9IP -- Steve Belter
Thanks to all for the refresher on the 5500 repair. I replaced the 17806P (which I think has a 6v output) with a 7805. This fixed the problem. I had to recalibrate as my max readings in the SatPC32 rotor calibration routine dropped because of the assumed lower output voltage of the 7805 regulator. I could only get a max azimuth reading of 206, somewhat less than the 255 needed, but this seems to work ok.
Does anyone know a source for a replacement bulb in the display? Both my bulbs are burned out and I would like to replace them with something I can obtain locally. Thanks again for all the help...
73 Jeff kb2m
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On Wed, Jul 27, 2011 at 06:45:34AM -0400, Jeff KB2M wrote:
Thanks to all for the refresher on the 5500 repair. I replaced the 17806P (which I think has a 6v output) with a 7805. This fixed the problem. I had to recalibrate as my max readings in the SatPC32 rotor calibration routine dropped because of the assumed lower output voltage of the 7805 regulator. I
Put a pair of silicon diodes between the ground end of the 7805 and actual ground.
http://bybeelabs.com/uploads/J0308_Dac_Applications.pdf
I was going to suggest this trick before, but thought you had already ordered a 7806. This will increase it to just about perfect. You might even get away with a single diode.
While you are in there, don't forget to bypass the input and output with a little more capacitance. The ceramic they have shown in the schematic is insufficient. The 7806 itself can start oscillating making a noisy racket all over HF and VHF. I used a 4.7uf since I had one lying around.
http://www.sunsunsun.net/kd4app/amsat/g5500.htm
- 73 Diane VA3DB
participants (6)
-
Alan P. Biddle -
Diane Bruce -
i8cvs -
Jeff KB2M -
Peter Portanova -
Stephen E. Belter