ETX-125 CIRCUIT BOARD REVS Last updated: 25 February 2011

Subject:	meade etx-125
Sent:	Wednesday, February 23, 2011 19:40:01
From:	Fernandez (fernandez@sympatico.ca)
My meade circuit board 15-6305-00 Rev b is not working. I managed to get
a rev C, but it has 2 extra pins where it hooks up to the scope. Are
they interchangeable. Thanks

David

And:

From:	richard seymour (rseymour@wolfenet.com)
My sheer guess is that the pins may be for the LNT communications in an
ETX125-PE?

(i've never seen the guts (nor outsides) of an ETX-125)

good luck
--dick

And:

From:	P. Clay Sherrod (drclay@tcworks.net)
I do believe that Dick is right; the boards are interchangeable and the
two pins are for the LNT connection; this is similar to the new LX200
GPS boards which all have two extra pins that are used only for the 14",
to connect the microfocuser to the fork arm port. Other than that, they
are interchangeable.

Dr. Clay
_____
Arkansas Sky Observatories
MPC H45 - Petit Jean Mountain South
MPC H41 - Petit Jean Mountain
MPC H43 - Conway West
http://www.arksky.org/

And:

Gentleman,
Thank you kindly for your help. I will try the install and see how it goes.
Regards,
Duncan

And more:

From:	andrew johansen (johansea@optusnet.com.au)
The extra pins ARE for the LNT/AUX but it wont work
as an LNT feed unless both ends are connected
( ie there is a new power panel connector to go with
with extra pins on the DEC card )
You MUST connect the 4 pin cable to the 6 pin connector
in the correct orientation or you may put 12V into the logic pins.
The pin closest to the "corner" of the board stays as 12V.
The extra pins are towards the middle of the edge
and should remain disconnected.
Other than that, it runs quite happily.

Andrew

And:

Thank you for your help. I'll provide some background. I have a Meade
ETX-125EC. Turned it on and the red LED on the interface panel came on,
but the Autostar 497 and the electronic controller would not light up or
work. My scope has the interface card Meade 15-6305-00 REV B, I have a
replacement which is REV C. I power up the Rev C and the Autostar powers
up but the scope motors don't work. Rev C has two extra pins on it to
hook up to the DEC and RA card, I plugged in the connector in several
possible locations but no motor action. I think I need the pin out to
reconfigure the connector. Thanks in advance.

Duncan

And:

I wish that you had not been "experimentally plugging" wires into pins
that are not identified; this is one of the reasons that Meade has
ceased selling parts to individuals. One wrong connection and you can
blow your entire system.  You cannot simply plug one device's connectors
into unknown pins until you hit a hot line with bad results.

Hopefully this are not going from bad to worse on this problem.  You
should have plugged to the NEW panel exactly as the wires came off of
the old panel.

Dr. Clay

And:

I agree with Doc here, you can't just swap the connectors as you risk
putting 12V into a clock or data line and if you do that, the motor card
gets fried.
Also, you do not need to "reconfigure" anything,
as the old plugs fit pin for pin to the new control panel card.

I have attached a picture of the connections for an ETX125PE control
panel. This is from my test bench, so i cant guarantee what colours your
cables are, ( or what orintation your plugs are ), and Meade are very
bad at any consistency here. ( Ie on all my 497 type scopes, Meade use
Black for 12V and red for ground???? ) However, the 12V and ground wires
are easy to check/confirm with a multimeter. In the photo, you can see
where the plugs for the RA and DEC are "supposed" to go and where the
two new pins ( Aux) have been added.

In your case, the ones marked Aux should have been left unconnected.
Just for starters, refit your RA cable only and see if you can get any
motion. If so plug in the DEC and try again. ( Power must be off for
plugging )

Andrew

And this:

This is a great illustration Andrew; Mike, this is something that needs
to be added to the ETX site and prominently displayed for reference.

Dr. Clay

And:

If that was to be the case, i would hold off a bit.
I mentioned Meades penchant for mixing up colours of wiring.
Ie ref the two new photos i have just attached.




One is my pre PE ETX (top) and one is a PE ETX (bottom)
note how the blue/yellow wires swap over in the PEs DECcables?????
( Its not a pinswap, just a complete cable transposition, colour wise )
Can be very confusing.
I also have a full wiring diag, and that may be a better solution
( or i may make up a little document with the diag and pictures )

Andrew

And more:

Thank you so much for solving my problem. Andrew, your picture with pin
outs fixed things for me perfectly. I put the 8 pin connector to the far
left of the new board (thus skipping the Aux inputs), and fixed one
loose wire going into the connector and the motors fired up! Mike your
site is a real charm, and I must thank all of you for your kind
assistance.
Clear skies,
Duncan

Picture of my dead rev B 8 pin board


Picture of my good Rev C 10 pin board

And:

Go out and buy a lottery ticket ( or two )  then ;-)
You appear to have been extremely lucky.

Andrew

PS Normally, if its only the interface panel that is dead,
it is blown traces and these can normally be seen easily
and bridged with a bit of copper wire. 
Heaps of posts exist on doing this.

And this:

I see Duncan has the same sort of base as my ETX
( i got one of the first ETX-125s with Alloy forks )
and it has a much better RA bearing setup than the PEs.

Andrew

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