---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Sat 05/12/12: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:26 PM - KI 209A and Century I Problems (Chuck Birdsall) 2. 11:23 PM - Re: KI 209A and Century I Problems (galsys) ________________________________ Message 1 _____________________________________ Time: 04:26:21 PM PST US From: Chuck Birdsall Subject: Avionics-List: KI 209A and Century I Problems I have a Grumman in my shop with a Century 1 autopilot that derives its left/right input from a KI204 or a KI209A via a 4P3T switch. The KI209A can be switched to act as a GPS CDI from a KLN94 or as a VOR CDI. The owner says that when the autopilot is connected to Nav 1 (KX170/KI204) it captures the radial just fine with a minimum number of overshoots. When it's connected to Nav 2 (KX170 or GPS/KI208A), it continually S-turns across the radial (or course line supplied by the GPS). The owner had the 209A/KLN 94 installed about 2 years ago and he says it never worked right from the time was installed (I'll not go into why he didn't just take it back to them ...). Both VOR systems indicate the appropriate course deflection when checked with a flightline tester. When the 209A is set for GPS mode, it displays the appropriate deflection during GPS self test (1/2 right). I checked the wiring and switch - there is continuity between the autopilot output of each CDI to the autopilot Left/Right input when switched in and are open when switched out. Each of the wires are appropriately open to ground, and there is no continuity between them. Both CDIs put out 150mV at full scale, 75 mV at half scale, etc. The 209A also puts out the right deflection voltage when switched to GPS mode. The only difference I noticed: The Left/Right reference voltage out of the 209A is about 4.15 V (appropriate per the 209A maint manual), but the reference out of the 204 is around 350mV. I could find no mention of the reference voltage in the 204 maint manual. The 209A manual says that the output is designed for a 1Kohm load. The Century install manual says the input to the autopilot presents no load. SO ... do I have a problem with one of the indicators? Do I need to load the output of the 209A in some way? Or is there some other problem? Thanks, Chuck ________________________________ Message 2 _____________________________________ Time: 11:23:16 PM PST US From: "galsys" Subject: Re: Avionics-List: KI 209A and Century I Problems you better check your Century a/p behavior instead of wasting your time on the NAV parts! Gabe ----- Original Message ----- From: "Chuck Birdsall" Sent: Sunday, May 13, 2012 1:25 AM Subject: Avionics-List: KI 209A and Century I Problems > > I have a Grumman in my shop with a Century 1 autopilot that derives its > left/right input from a KI204 or a KI209A via a 4P3T switch. The KI209A > can be switched to act as a GPS CDI from a KLN94 or as a VOR CDI. > > The owner says that when the autopilot is connected to Nav 1 (KX170/KI204) > it captures the radial just fine with a minimum number of overshoots. > When it's connected to Nav 2 (KX170 or GPS/KI208A), it continually S-turns > across the radial (or course line supplied by the GPS). The owner had the > 209A/KLN 94 installed about 2 years ago and he says it never worked right > from the time was installed (I'll not go into why he didn't just take it > back to them ...). > > Both VOR systems indicate the appropriate course deflection when checked > with a flightline tester. When the 209A is set for GPS mode, it displays > the appropriate deflection during GPS self test (1/2 right). > > I checked the wiring and switch - there is continuity between the > autopilot output of each CDI to the autopilot Left/Right input when > switched in and are open when switched out. Each of the wires are > appropriately open to ground, and there is no continuity between them. > > Both CDIs put out 150mV at full scale, 75 mV at half scale, etc. The 209A > also puts out the right deflection voltage when switched to GPS mode. > > The only difference I noticed: The Left/Right reference voltage out of > the 209A is about 4.15 V (appropriate per the 209A maint manual), but the > reference out of the 204 is around 350mV. I could find no mention of the > reference voltage in the 204 maint manual. > > The 209A manual says that the output is designed for a 1Kohm load. The > Century install manual says the input to the autopilot presents no load. > > SO ... do I have a problem with one of the indicators? Do I need to load > the output of the 209A in some way? Or is there some other problem? > > > Thanks, > > Chuck > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message avionics-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Avionics-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/avionics-list Browse Digests http://www.matronics.com/digest/avionics-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.