EQ5 drive

[Stargazer292]

Hello everybody,
I'm going through a bit of a trouble with my EQ5 or CG-5.
I started supplying power through an AC adapter with 6VDc.
Doesn't seem to track properly even though I don't perform a perfect polar alignment the star just runs away from the eyepiece.
I read somewhere that the step driver circuit uses the internal resistance of the batteries. So it seems that if you supply a stabilized tension the driver shouldn't work properly, it may even burn the steppers transistors.
I tried to use a sealed lead acid battery but I encountered the same problem.
Someone suggests to place a 2 Ohm 5Watts to the power supply, would it help if I use the SLA battery?
what can I do to fix or try to fix the problem?
Thnks

[Karls48]

Provided that you supply correct voltage to your controller the only time you can damage some controllers by using SLA battery would be if the mount hits hard stop or it seize. AC adaptor has to be regulated type. If you used unregulated adaptor you may have damaged your controller. Other most likely cause of tracking problems are: badly balanced mount, bad polar alignment, gear slipping on the shaft or badly meshing gears.

[Glenhuon]

I use a home built regulated 6.3 volt convertor attached to a 12 SLA to run mine with no problems. I would be wary of using a 240v plug pack type, I destroyed my original controller with one of those. Took me a while and quite a few dollars for a replacement. I can post a circuit for the regulator if you want it.

Bill

[Stargazer292]

Very much appreciate it, can you please send me the circuit?
Thanking you.:thumbsup:

[Glenhuon]

This is the url for where I got the circuit. http://ourworld.compuserve.com/homepages/Bill_Bowden/page12.htm
I found the LM317T got a bit too warm during operation so used the TO3 package LM317K mounted on a small heatsink on the outside of the plastic case. The first circuit will easily handle the EQ5 drive if the regulator substitution is made. For more current look at the second circuit with the pass transistor. He specifies 380 Ohm for 6V, but I found using the standard 390 Ohm resistor only increases the output by about 0.5v, which is fine as new batteries will deliver that anyway. Battery/Box look a bit dusty, but they been outside for a few days :)

Cheers
Bill

[Stargazer292]

Thanks a lot Bill.
If the worst case scenario is that the drive is damaged, what is that normally get damaged, what components?
thanks

[Glenhuon]

What got damaged on mine was the controller chip. It worked intermittently, more often not. Unfortunately there's no replacements available as they are programmed by the producer and they won't provide one on its own. I talked to the Aus supplier and they won't even give them one, the factory never answered my email. The chip is a once only programmable processor. You can get them, but not the program. Hopefully yours will be OK once it gets the correct smoothed voltage. Try it with the battery pack again, if it works OK then your in luck.

Bill

[Stargazer292]

Let's cross fingers. Would the Mel Bartel's software and hardware be able to drive the two motors of the Eq5? If yes that would be great, I would give it a go.

[Glenhuon]

Can't help you with that one, never used the Mel Bartle stuff, but I'll kook it up. My replacement controller has the Parallel Port fitted (done by previous owner) but have never used it so far.

Cheers
Bill