Fw: CP3 & CP4 - Last command persistence


Joe Zeglinski
 

Thanks Rolando,
 
    You may be right – the CP4 problem is now permanent, with a solid AMBER LED.
– Hope to hear from Howard soon, after a brief rest from his conferences.
 
    Sure seemed like a “motor related” problem ... at first ... but unlikely BOTH motor encoders would have failed simultaneously.
Interestingly, the DEC motor didn’t move at all, as the RA motor slewed across the sky, starting from a Park-1 position and ending up in exactly the same way pointing North, now on the pier East side – not even the standard Park-4 orientation there, when I finally managed to stop it going even further, under the mount.
 
Things I tried:
    I switched to a different set of Y-cables, which didn’t fix it.
Tried a different 10 amp supply – with nothing else connected on the scope except the CP4 electrical load itself – still no go.
 
    Tried a fully “MANUAL operations”  test - (no PC,  or any serial or guider cable plugged in) -  using first one handpad, then another spare unit – all handpad functions seemed to work on the CP4, “except the slew buttons, or any PARK” commands – Since the CP4 which has no feedback to the handpad,  then maybe it is not even seeing any inputs that affect its own internal operation. The handpad port,  and probably also the CP4 serial port  I was using to drive the mount with the laptop,  are likely both dead, or the firmware has locked up tight.
 
    Finally switched back to using  “old faithful”, the CP3 on that AP-1200 – now the mount works as it should, either one of the handpads slews & Parks – using either one of the  Y-cables.
 
    Then I switched the failed CP4 to my indoors portable field mount, with no scope or even a cwt. bar on it – i.e. “perfectly & lightly balanced” with  different cables, different motors, on the AP-900 – and the CP4 was STILL  dead,  with its shining Amber LED status.
    Can’t think of anything else to swap test, or try differently to nail down this recurring problem.
 
    Ran the new SGP-PRO software through the exact same steps as before, and could not make the software repeat the runaway fault,  using the old CP3. So, something suddenly went squirrely inside the CP4. Maybe it  needs user replaceable  internal fuses rather than just a battery plug general load fuse. Probably wouldn’t have helped since the CP4 mount had been sitting quietly idle in Park-1, for two and a half hours on a cool beautifully clear night, before it suddenly glitched. So, not a matter of overheating the motors with a lot of GOTO’s, and I didn’t even launch a Planetarium program at the time.
 
    The CP4 doesn’t seem quite sustainable, unfortunately, compared to the CP3’s.  Now, THAT was a solid, lower tech product with few things that could wrong too easily.
Quite regrettably,  this isn’t the first time both my CP4’s have had this weird kind of problem, just over the past year.
 
Joe

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