PDA

View Full Version here: : LX200 12v out current draw


Shawn
28-08-2006, 05:45 PM
Hi all , does anybody know if the 12v out on the LX200 is limited in any way to the supply current..thats the 12v out on the fork mount, its not in the manual...

Cheers

shawn..

h0ughy
28-08-2006, 07:55 PM
go to the MAPUG web site, you may find your answer there

Gama
28-08-2006, 09:49 PM
The output 12V from the base is normally limitted to around 500mA. But personally i would NOT use it. Make a boo boo and say bye bye !!.
Use an external supply.

AndrewJ
29-08-2006, 12:35 PM
Assuming you mean an LX200R, and the mainboard is similar to the LX200GPS, then a mob in the states has reverse engineered the boards and supplied circuit diags.
http://www.telescopeservice.com/lx200gps.htm
For the 12V output, based on these diags ( Mainboard IO ), there is an inline 5ohm resistor, and the switching is provided via a P channel mosfet.
Thus ohms law will tell you what you can draw before the voltage drop across the resistor gets too high, or the bits fry.
Ie if you draw 500mA, you will get a 2.5V drop across the resistor
so if yr supply is 12V, you will only be getting 9.5V out
So, its not real useful for any large loads

Merlin66
29-08-2006, 05:40 PM
I ended up making a small ( 75 x 50 x 25) breakout box which velcro's on the side of the control panel. This gives me a 12V / 18V output and I added some switches to allow better control of the #1206 and micro focusser from a separate hand paddle. Works great!!!!
Also have made up the PWM controller for the dew heater and used the 13 Ohm NiChrome wire from Jaycar mounted in a strip of 25mm Velcro... works a treat I can "dial" in the temp difference required.

Gama
29-08-2006, 08:53 PM
Much better, this way you dont fry nothing..