Forum

Notifications
Clear all

This Forum is a place for Piper Comanche pilots to communicate and discuss technical issues

If you join or reset a password, please check your Spam Email box for emails from Admin at ComancheTechTalk.com

Please put your questions on the forum as well so everyone can read and respond. Someone else might be having similar questions.

All questions or topics on the Forums automatically get sent to the Tech team as well.

Altimatic II B Roll problem

1 Posts
1 Users
0 Reactions
65 Views
Admin
Joined: 5 years ago
Posts: 1162
Topic starter  

Altimatic II B Roll problem

Postby Donald Moreau » Mon Jun 04, 2012 2:14 am

I just recently purchased a Twin Co with altimatic II B, and when you turn the roll on it won't work. The altitude hold works, but if I turn the roll switch on, I can hear the servo but it doesn't turn the yoke. It has the rectangular box servo on the firewall. Hopefully I can adjust the clutch in the servo. Before I started taking anything apart I was wondering if anybody has done this before? And if anybody has any input it would be greatly appreciated.
Donald Moreau
 
Posts: 1
Joined: Mon Jun 04, 2012 12:12 am

Re: Altimatic II B Roll problem

Postby md11flyer » Mon Jun 04, 2012 4:58 am

Sometimes its a matter of lack of use . Sounds like the servo soleniod is not doing its job. There are 2 reasons it doesn't work properly.. one is its gummed up with dirt and oil, second is the ground to the solenoid is compromised by either the 40 year old "grey wires" or connectors. You could check the solenoid / servo by swapping it out with a known good servo. If the good servo also gives the same symptoms, then you have a cable / coonector problem, if the new servo works well then you now know the servo/solenoid needs overhaul.
Have you had avionic work lately? Sometimes when you muck with the grey cables connecting the autopilot components, some of the 40+ year old wires and the connectors fail. I have personally have had. the same problem with the grey wire symptoms after a panel upgrade. The rerouting of these old wires caused a ground wire to separate from the connector to the ADI,
causing various problems that were only solved after ohmning the grey wires to the ADI.
I hope this helps,
God luck
Gary
md11flyer
ICS member
ICS member
 
Posts: 330
Joined: Tue Mar 24, 2009 3:48 pm

Re: Altimatic II B Roll problem

Postby steen » Tue Jun 05, 2012 7:47 am

Donald,
I would bet that the clutch has been overeridden and disconnected by manually countering the autopilot with control inputs.
This requires a mechanical re-connect at the servo.
The other possibility is a corroded box under the #3 pass. seat floorboard that, when cleaned up, performs remarkably....like new!
Good luck. It's a great autopilot.....years ahead of it's time.
Steen
steen
ICS member
ICS member
 
Posts: 168
Joined: Thu Sep 30, 2004 3:24 am
Location: Palatine, Il. USA
  •  
  •  

   
Quote
Share: