DesertNomad
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This is in a PA28-236 Dakota.
Previously I had a GTN750 hooked to a MD200-706 and a GNC255 hooked to a GI-106A. I removed the GI-106A completely and connected the MD200-706 to the GNC255 because the 750 is now connected to dual G5s. At the same time I removed both vacuum gyros and the suction gauge along with the associated hoses.
My MD200-706 needle is vibrating at a high frequency fore and aft. After testing a new GNC255 as well as a new indicator, we narrowed it down to a vibration in the panel. It was happening between 2260 and 2360rpm and after rebalancing the prop (now 0.04 on the balance tool), now does it between 2210 and 2310rpm. With the CDI out of the panel on a long cable/wiring, holding the instrument against the panel causes it to vibrate.
I figure it is related to removing mass from the panel (both gyros) as well as the hoses that ran to the firewall to connect to the (now-removed) vacuum pump.
Any ideas on how I can eliminate the vibration?
The screw holes in the panel are counter-sunk so even with a thin gasket over the instrument, the screws are going to be against the metal panel.
I am not sure if the reason it didn't do it before is the additional mass on the panel or the rubber vacuum hose being connected to the firewall.
Previously I had a GTN750 hooked to a MD200-706 and a GNC255 hooked to a GI-106A. I removed the GI-106A completely and connected the MD200-706 to the GNC255 because the 750 is now connected to dual G5s. At the same time I removed both vacuum gyros and the suction gauge along with the associated hoses.
My MD200-706 needle is vibrating at a high frequency fore and aft. After testing a new GNC255 as well as a new indicator, we narrowed it down to a vibration in the panel. It was happening between 2260 and 2360rpm and after rebalancing the prop (now 0.04 on the balance tool), now does it between 2210 and 2310rpm. With the CDI out of the panel on a long cable/wiring, holding the instrument against the panel causes it to vibrate.
I figure it is related to removing mass from the panel (both gyros) as well as the hoses that ran to the firewall to connect to the (now-removed) vacuum pump.
Any ideas on how I can eliminate the vibration?
The screw holes in the panel are counter-sunk so even with a thin gasket over the instrument, the screws are going to be against the metal panel.
I am not sure if the reason it didn't do it before is the additional mass on the panel or the rubber vacuum hose being connected to the firewall.
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