[amsat-bb] Elevation meter Rotor YAESU G-5500 stopped working

[W3AB/GEO]

Norm,

He should make sure it is not an external issue before he dives into the internal circuitry.

He should also check that the controller is operating before opening the controller.

Albert, take a VOM, set it on AC and the 50V range if it isn't autoranging. Turn on the controller. Put 1 lead on pin 6 of the terminal strip, the other lead on pin 4 and operate the up/down switch. Do the same for pin 5. If the controller is operating correctly you should measure ~30V. If not, you have an internal failure and follow Norm's advice.
⁣___
Sent from my two way wrist watch
73 de W3AB/GEO​

On Jul 18, 2017, 16:50, at 16:50, Norm n3ykf <normanlizeth at gmail.com> wrote:
>Albert,
>
>Take EXTREME CARE working on equipment that has power applied.
>
>You'll need a copy of the schematic. Preferably the one that came with
>the controller/rotator. There are at least two different power op-amp
>power supply layouts. One with a pass transistor and zener diodes, the
>other a 75L10 regulator.
>
>Unplug the control box.
>
>Remove the top cover. Remove the front two screws from the bottom
>cover. This will let the face (meters, circuit board and switches)
>free. (still wired to the rest)
>
>Get two books. Turn the front face down on top of the books, switches
>between the books. (to allow the assembly to sit level and not
>press/break the switches)
>
>
>MAKE SURE THE UNIT IS UNPLUGGED!!!!!!!!!!!!!!!!!
>
>
>Q4 is one half of a 4558 op amp pair(two on one chip, the other runs
>AZ output for the aux jack).
>
>Find Q4.
>
>You're mission is to check the various components making up the drive
>circuit for the EL meter for trouble.
>
>Could be:
>
>Shorted capacitor
>
>Open diode
>
>Short or open via other means.
>
>MAKE SURE THIS IS UNPLUGGED!!!!!!!!!!!!!!!!!
>
>Use an Ohmmeter to look for capacitors that aren't open (Should look
>close to it, at least the values in the circut. Electrolytics are a
>different story...) Look for open diodes. Meter anything reasonably
>accessable, starting from the wiper on VR2 on the back panel. Some
>things are best looked at with respect to ground, others point to
>point reading the components in between.
>
>DANGER!!! DANGER!!!! DANGER!!!
>
>This part of the test requires making power on voltage measurements.
>Here be dragons, or a trip to your eternal reward!!!
>
> Locate L2 and L4. Those components (each in their seperate circuit)
>form the power supplies (rails) for the EL op amp. See C1 (the voltage
>output) next to L2? C2 likewise next to L4?
>
>Check the pins 8(C1) with respect to ground and 4(C2) of Q4. These are
>the power supply rails (should be +/- 12 volts or so).
>
>Before plugging it in to test, make sure no bare wires are touching
>things they should not be.
>
>Plug it in (you did leave the power switch on, didn't you??). Test
>away. UNPLUG IT AS SOON AS YOU'RE DONE!!!!
>
>Have fun and don't break anything. A fire here is a failure.
>
>Norm n3ykf
>
>On Tue, Jul 18, 2017 at 5:56 PM, Albert van Deursen <avdeur at home.nl>
>wrote:
>> Hi all,
>>
>>
>>
>> All of a sudden the elevation meter stopped working of my Yaesu
>G-5500 rotor
>> controller unit .
>>
>> No issue with the AZ meter. Rotor itself keeps on steering / working
>> without any problem in EL &AZ (via interface EA4TX ARS-USB) so all
>still
>> working fine (fortunately !)  for satellite work.
>>
>> Looks like a component failure in the controller unit  or the meter
>itself ?
>>
>>
>>
>>
>> A physical check (opening the controller unit) didn't show any
>anomaly.
>> Being a not too tech ham was wondering if any of you Yaesu rotor
>users had
>> seen this problem before / around ?
>>
>>
>>
>> Possibly anyone to hint/ indicate at a quick check in the schematic
>wire
>> diagram to where to start looking for this failure ?
>>
>>
>>
>>
>>
>> Thanks beforehand for yr appreciated advice
>>
>> 73
>>
>> Albert
>>
>> PD0OXW
>>
>>
>>
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>_______________________________________________
>Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
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>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb