18v dc power to older LX200
Don Lockhart
supply. I did get a 12v rechargable dry cell battery, and cigarette lighter
adapted for it. When I asked the dealer about purchasing one, he said he
didn't have one in stock but would order it for me. Then he called me later
that day to say that he had called Meade Tech Support and they recommended I
buy/use the newer 18v dc power supply on the older 12v system.
I'm no electronics whiz... is there anyone out there who can tell me if this
is ok or not? They stated it (my LX200 12vdc) would run "more effeciently"
under 18vdc.
Comments?
Regards,
Don Lockhart
43=B040'46.4367"N 70=B015'28.0053"W
mailto:dl...@nlis.net
url=3D http://www.nlis.net/~dlock
Member - Astronomical Society of Northern New England
Check our homepage at http://www.nlis.net/~mesky
RLE...@aol.com
>I'm no electronics whiz... is there anyone out there who can tell me if this
>is ok or not? They stated it (my LX200 12vdc) would run "more effeciently"
>under 18vdc.
>
>
yes........................
ric
DT...@aol.com
voltage. Most LX 200's will run on 12vdc, but Meade no longer recommends it
(per John Piper). My scope, even though the packing list included a 12vdc
power cable, didn't come with one. On researching this I found out the
following:
1. The computer electronics operate on precisely regulated 5vdc (and some
other low voltages) whether the input is 12 or 18 volts.
2. The servo motors operate on a less highly regulated power supply derived
from the input voltage. The servo motors will always require the same power
(watts) to operate at at their crystal controlled rpm. Since watts = voltage
X current, if the voltage goes down, the current goes up. This can get
critical when a car battery, etc., gets to 10 volts and below, causing the
servo motors to draw so much current that they burn up themselves and usually
their op-amp drivers as well.
3. This is why Meade came out with the electronic dc to dc convertor, and it
will not let the input voltage to the scope go below a certain level (not
sure what), before it shuts down.
4. If your power panel says "12vdc", call John Piper at Meade for advice.
P.S. I still use 12vdc from a marine deep cycle 80 amp battery. I have run it
for 12 hours straight with no problems. Theoretically, it would take about 20
hours for the LX200 to drop this battery to 10 volts, but I don't push my
luck. Don't tell Meade :).
--Don Tabbutt
Frank Nowling
Connector", there is this statement: "The acceptable voltage range
(under load) is from 12 to 18 volts."
I have been running my older "12vdc" system with the Meade 12v to
18v converter for about 8 months (1-3 times a month). I have
observed no ill effects, and I think that it actually runs a little
quieter.
Frank
+----------------------------------------------------------------+
Frank L. Nowling III - fnow...@neosoft.com - Houston, TX
9,932,339 Galaxies, 9,932,340 Galaxies, DAMN! 1 Galaxy, 2 Galaxies
Pgo...@aol.com
>Arnaldo,
>
> My LX200 is 3 years old, but has had the motherboard and hand controller
>replaced to v3.20 on the hand controller, and v3.30L on the roms. The dealer
>(who may not really know) told me I had the latest hardware (which I don't
>if you consider the v3.34 roms available now). He called Meade to order a
>power supply and Meade recommended the 18v since the system had the upgrade.
>But I would think the real deciding factor would be the motherboard, as the
>servo motors are probably more resiliant to changes in voltage. Meade even
>went so far as to tell him it would run better under 18vdc.
>
>Regards,
>
>Don Lockhart
Let me jump into the fray a bit here.....
While I have no actual circuit level knowlege of what goes on inside the
LX200, I understand that the servo motors, and indeed everything else, are
the same for the 12V and the 18V telescopes. Meade merely increased the
input voltage to the scope by revising the AC adapter and making available a
12V to 18V converter.
The difference seems to be twofold...
First, the motors operate from the "raw" un-regulated input power and
therefore run faster, allowing a faster slew and greater torque. Second,
there is more "headroom" between the input voltage and the internal
(regulated) logic voltage, reducing computer glitches caused by incoming
power glitches that get past the on-board regulator(s).
I own an 18V LX200, but I use it exclusively on 12V because I use it outdoors
on battery power and I'm too cheap to buy the 12V to 18V converter. Works
fine.
Hope this helps (and is accurate!).
Paul
Arnaldo Arnal
I am not that sure ! If you have an old version of the LX system which was
made to run on 12 volts, you should use it with 12 volts, and not with 18 v.
If you buy a converter of poor quality once you start your telescope maybe
you will only get 14 volts, but if your telescope was made for 12 volts, go
for 12 volts only. Mine is 18 volts, but it might be a new version.
Arnaldo.
Don Lockhart
>>
>>>I'm no electronics whiz... is there anyone out there who can tell me if=
this
>>>is ok or not? They stated it (my LX200 12vdc) would run "more=
effeciently"
>>>under 18vdc.
>I am not that sure ! If you have an old version of the LX system which was
>made to run on 12 volts, you should use it with 12 volts, and not with 18=
v.
>If you buy a converter of poor quality once you start your telescope maybe
>you will only get 14 volts, but if your telescope was made for 12 volts, go
>for 12 volts only. Mine is 18 volts, but it might be a new version.
>
>Arnaldo.
Arnaldo,
My LX200 is 3 years old, but has had the motherboard and hand controller
replaced to v3.20 on the hand controller, and v3.30L on the roms. The dealer
(who may not really know) told me I had the latest hardware (which I don't
if you consider the v3.34 roms available now). He called Meade to order a=20
power supply and Meade recommended the 18v since the system had the upgrade.
But I would think the real deciding factor would be the motherboard, as the
servo motors are probably more resiliant to changes in voltage. Meade even
went so far as to tell him it would run better under 18vdc.
Regards,
Don Lockhart
Don Lockhart
>If your older LX200 says "18vdc" on the power panel, then try to use that
>voltage. Most LX 200's will run on 12vdc, but Meade no longer recommends it
>(per John Piper). My scope, even though the packing list included a 12vdc
>power cable, didn't come with one. On researching this I found out the
>following:
>1. The computer electronics operate on precisely regulated 5vdc (and some
>other low voltages) whether the input is 12 or 18 volts.
>2. The servo motors operate on a less highly regulated power supply derived
>from the input voltage. The servo motors will always require the same power
voltage
>X current, if the voltage goes down, the current goes up. This can get
>critical when a car battery, etc., gets to 10 volts and below, causing the
usually
>their op-amp drivers as well.
it
>will not let the input voltage to the scope go below a certain level (not
>sure what), before it shuts down.
>4. If your power panel says "12vdc", call John Piper at Meade for advice.
Don, the recommendation I mentioned "from Meade" in the original note was=
from
John Piper who was made aware that this was a 3 yr old scope which had had=
the
motherboard and keypad upgrade to 3.30L. Joh recommended the 18vdc ps. I=
just
wanted to bounce it off some "virtual electronics engineers" here on the=20
mapug as I hadn't heard of upping the dc voltage on anything before,=
especially
something with a circuit board, but it makes sense that it's all regulated
anyway.
I found an 18vdc power supply in the Starry Messenger at less than half of=
what=20
the dealer wanted for it... So I'll feel comformtable using it now. Thanks!
Dark skies...
Regards,
Don Lockhart
43=B040'46.44"N 70=B015'28.01"W
RLE...@aol.com
>I am not that sure ! If you have an old version of the LX system which was
>made to run on 12 volts, you should use it with 12 volts, and not with 18 v.
>If you buy a converter of poor quality once you start your telescope maybe
>you will only get 14 volts, but if your telescope was made for 12 volts, go
>for 12 volts only. Mine is 18 volts, but it might be a new version.
>
>Arnaldo.
Ok, I'm a bit more long winded today !!!
I have the 12volt version which works fine on 12v. It also works fine on
18v because I built my own 12 to 18v converter. The converter puts out 18vdc
at 500 ma. + or - a tenth of a volt. I have so much extra weight on my scope
that I felt it needed an extra boost it gets with the 18v. Your scope will
problable work just fine a 12 volt also, Meade just changed the silk screen
on the scope because some of the scopes were blowing fuses at 12v. Meade
also boosted the voltage on the 110vac - 12vdc to 18vdc.
I hope this helps.............ric
Bill Arnett
>...
>P.S. I still use 12vdc from a marine deep cycle 80 amp battery. I have run it
>for 12 hours straight with no problems. Theoretically, it would take about 20
?? My impression is that an LX200 uses about 500 milliamps. That means
your 80 amp (-hour) battery should last 160 hours, not 20. Of course, you
might not want to take it down that far but 20 seems awfully conservative.
Am I missing something here?
---
Bill Arnett "Science is a way of trying
San Jose, CA USA not to fool yourself." -- Feynman
bi...@zNet.com <URL:http://www.seds.org/billa/>
DT...@aol.com
>?? My impression is that an LX200 uses about 500 milliamps. That means
>your 80 amp (-hour) battery should last 160 hours, not 20. Of course, you
>might not want to take it down that far but 20 seems awfully conservative.
>Am I missing something here?
You're right, of course. I should have said "including my dew heaters and
laptop computer".
John Lumpp
cli...@bconnex.net
<Can anyone tell me if the NGF-S focuser will work from the LX keypad?>
Yes it does. Just plug into the focus jack and go. Don't forget that
you have two speeds. Adjust to rough focus manually then use the
slower speed. I find that the high speed runs through the focus too
often.
Cliff
Bill Arnett
that the JMI will eliminate focus shift. On a 12" it would seem that the
JMI focuser would also make it impossible to swing the eyepiece thru the
forks.
W. Miller
>Can anyone tell me if the NGF-S focuser will work from the LX keypad?
Yes it works, but the slow speed focus is fast and the fast speed
is hyper fast. I did not like it this way, so in the wire from the
LX-200 jack to the NGF-S I placed some resistors, 390 ohms in series,
and 560 ohms in parallel on the NGF-S side to form a voltage divider.
If you open up the NGF-S hand controller you will see that it's
slow-fast control works this way to adjust the voltage to the motor.
I measured 7.5v fast and 16v slow out of the LX-200 jack. The hand
controller produced 2.5v slow and 9v fast. Measurements were made
with the motor load present, 6ma slow and 10ma fast.
Bill Miller, Los Gatos, CA