[TowerTalk] Repairing Yaesu G-800SA

Tue Jan 26 05:12:48 PST 2010

These connectors are available from Yaesu but are quite expensive. A friend
of mine had to order a set a couple of years ago and paid 80+ dollars for
one connector to fit the rotor and one for the control box.

Julio, W4HY

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Terrence R. Redding
Ph.D.
Sent: Tuesday, January 26, 2010 12:14 AM
To: Perry - K4PWO
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Repairing Yaesu G-800SA

Good evening.

I have had a chance to consider the MDS controller, and I must say my
initial impression is good.

The MDS RC-1 is physically a third the size of the Yaesu controller. The
first thing I did was plug it in.  Rather than a dial, it has a bright blue
display that is easily read in daylight from across the room in my shack.

The provides a three digit directional display and the cardinal direction.
There is also a lower display for the CMD direction, and the GOTO direction.
I assume the CMD direction comes from the serial connector, and the GOTO is
set by a GOTO knob.  Then there is also a CW, CCW, and GOTO buttons that
allow you to fine tune the direction and cause the beam to move to the GOTO
direction.

It is a very nice clean display.

When I first powered the MDS RC-1 controller it flashed in the lower middle
of the screen "CABLE."  Of course it was not connected to the rotor control
cable.  So when I connected it to the rotor cable I was in a way pleased to
see that the device still flashed "CABLE."

I have two G-800 rotor motors on my work bench.  One is new and the other is
15 years old.  Both are marked G-800.  But the older one has a much larger
round threaded male connector on the side with six large pins.  They are
labeled in a circular pattern with one at the top, clockwise till you reach
five, and then pin six is in the middle.  Pins two and three are associated
with measuring the direction, and pins four and five carry the DC voltage to
control rotation and direction.  It is as another had said, a matter of
reversing the polarity to change direction.  Both of my rotors on the work
bench work fine.  The problem is with the cable from the shack to the top of
the tower.  A test with an ohm meter shows it to be open.  So I will try
replacing the cable first, before doing anything else.

I do have a question. The new rotor motor has a smaller seven pin male
connector.  I am wondering if there is a source for the six pin and seven
pin female connectors that attach at the rotor motor end of the rotor
control cable?

Terry - W6LMJ

On 1/21/10 1:24 PM, "Perry - K4PWO" <k4pwo at comcast.net> wrote:

> Please let me know how the MDS controller works for you.  I've got a
G-800SA
> like you as well as an old G-500 elevation rotor that I'd like to
> computerize.  At $250 per controller, I would be hard pressed to "roll my
> own" for that cost.
> I sent this email direct so you can reply off group.
> 
> 73 de Perry - K4PWO
> 
> --------------------------------------------------
> From: "Terrence R. Redding Ph.D." <terry at oltraining.com>
> Sent: Wednesday, January 20, 2010 15:01 PM
> To: <towertalk at contesting.com>
> Subject: [TowerTalk] Repairing Yaesu G-800SA
> 
>> Okay Perry.
>> 
>> I ordered one.  It should be here in the next few days.  I am getting
>> ready
>> to run phone patch traffic for the SATERN net and 14.300 and need to be
>> able
>> to turn the tower.  Normally from here in West Palm Beach, Florida
>> pointing
>> the beam across the continent works just fine.  But if I want to run
>> patches, it is better to turn the house around.
>> 
>> Once the replacement is here I will start working to repair one of the
two
>> broken controllers.  Lightning as you might imagine is a problem here.
>> 
>> Terry - W6LMJ
>> 
>> 
>> On 1/19/10 5:10 AM, "towertalk-request at contesting.com"
>> <towertalk-request at contesting.com> wrote:
>> 
>>> Message: 1
>>> Date: Mon, 18 Jan 2010 19:58:00 -0600
>>> From: "Perry - K4PWO" <k4pwo at comcast.net>
>>> Subject: Re: [TowerTalk] TowerTalk Digest, Repairing Yaesu G-800SA
>>> To: "Tower and HF antenna construction topics."
>>> <towertalk at contesting.com>
>>> Message-ID: <281F9ABCA5C5431C8791F043D1A46E26 at Developement>
>>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>>> reply-type=original
>>> 
>>> I'm thinking of getting one as well
>>> The manual is on the Yaesu Web site and it has a controller schematic in
>>> the
>>> back (I can e-mail the PDF file if you don't find it).  Pretty straight
>>> forward circuit.  You have a DC power supply that produces a regulated
12
>>> volts for the electronics, and un-regulated 24 volts for the rotor.  The
>>> electronics mainly read the feedback pot's voltage in the rotor to drive
>>> the
>>> display compass rose motor and it's mechanically coupled feedback pot to
>>> the
>>> same voltage.  The equivalent of a "selsyn" system.  The rotation
>>> direction
>>> switches just cause the relays to close reversing the polarity of
voltage
>>> to
>>> the motor depending on the direction of rotation.  You have an internal
3
>>> amp. fuse in the 24 volt supply as well as the AC line fuse on the back
>>> of
>>> the controller.
>>> 
>>> 73 de Perry - K4PWO
>> 
>> 
>> _______________________________________________
>> 
>> 
>> 
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>> 

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