Thruster763 Posted November 8, 2011 Share Posted November 8, 2011 Hi, The early Herc's had relatively large (780uF & 3680uF IIRC) capacitors across the VOR/LOC and GS deviation circuits. Has anyone got a reference to the purpose of these? I assume that they were to damp vibration induced movement of the pointers in the old AQU-2/A HSI's and ARU-2B/A ADI's. This is based on dynamic braking, the pointer movement generates an AC voltage, capacitor "shorts" the AC voltage thus needing more input energy to produce the same deflection. I would however like a reference or anyone else's thoughts. I'm doing an upgrade and am going to pull them. At 30 years old and only a few hundred millivolts across them, some of it reveresed, I doubt they have much capacitance left and lots of ESR! Thanks in advance. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted November 26, 2011 Share Posted November 26, 2011 They were to dampen the signal to the autopilot to prevent excessive movement when the A/P was coupled to the Nav Aids. This is from the A/P troubelshooting section of the 1C-130B-2-8. If you remove them and have poirposing or yawing problems on approach, you'll know you still need them. I know a Little Rock bird had a poirposing problem a few years ago that was troubleshot to a bad Cap. This bird had the ARN147 VOR/ILS and the digital A/P installed. (C-130E and C-130H Airplanes Only.) If ripple is excessive, replace the glidepath radio output filter capacitor after checking airplane wiring. The No. 1 and No. 2 AN/ ARN-67 system output capacitors are designated, respectively, as C30RA and C30RB. These capacitors are located on airplanes AF61-2358 through AF61-2373 at radio junction box terminals 44 to 45 and 124 to 125, and on airplanes AF62-1784 and up in the navigation instruments switching panel. Quote Link to comment Share on other sites More sharing options...
Thruster763 Posted November 30, 2011 Author Share Posted November 30, 2011 Hi Tiny, Thanks for the reply. Do you recall what indicators were fitted to that airframe? not worried about the model, just if they were mechanical or "glass". Robert. QUOTE=tinyclark;24915]They were to dampen the signal to the autopilot to prevent excessive movement when the A/P was coupled to the Nav Aids. This is from the A/P troubelshooting section of the 1C-130B-2-8. If you remove them and have poirposing or yawing problems on approach, you'll know you still need them. I know a Little Rock bird had a poirposing problem a few years ago that was troubleshot to a bad Cap. This bird had the ARN147 VOR/ILS and the digital A/P installed. (C-130E and C-130H Airplanes Only.) If ripple is excessive, replace the glidepath radio output filter capacitor after checking airplane wiring. The No. 1 and No. 2 AN/ ARN-67 system output capacitors are designated, respectively, as C30RA and C30RB. These capacitors are located on airplanes AF61-2358 through AF61-2373 at radio junction box terminals 44 to 45 and 124 to 125, and on airplanes AF62-1784 and up in the navigation instruments switching panel. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted November 30, 2011 Share Posted November 30, 2011 We had the same basic setup with Analog indicators HSI, ADI during the ASIP I,II,III mods. Nav systems had digital signal outputs with a signal data converter (SDC) to drive the indicators. Quote Link to comment Share on other sites More sharing options...
tinyclark Posted December 1, 2011 Share Posted December 1, 2011 Old Analog ADI. The pitch bar could be seen barely oscillating on that L.R. bird. Quote Link to comment Share on other sites More sharing options...
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