Guitarmaster

Much thanks to marauder and tee jay for your schematic contributions! Sent from my iPad using Tapatalk

In reviewing the schematic for the hundredth time, there are two possible culprits. A diode and a resistor. I am guessing the diode is bad. Now... Time to physically locate the diode. This should be fun. :/ Sent from my iPad using Tapatalk

Ok. I have studied the schematics and am a little stumped. When the nav lights are on, it completely disables the gear down sensing system. I am reasonably sure it is only supposed to dim. The schematic shows a straight wire between the nav light switch and the GEAR DOWN indicator light. To me, it looks like a dead short. Obviously it's not. It is one of the strangest schematics I have ever seen. Here is the question. Is there a relay, resistor, fuse in that circuit that would be used for dimming that is not shown on the schematic. If so, where is it located? Sent from my iPad using Tapatalk

I just thought I would let you guys know, the problem was a small amount of water that had frozen around the holes in the sump. Problem solved with just a little warmer weather. [big sigh of relief!] It was a surprisingly small amount of water. Well, live and learn. That was a new one on me. Now on to bleeding the brakes, troubleshooting the PC system and a visit to the radio shop to get the HSI working properly. Cheers!

Marauder.. I will definitely keep a lookout for the worms. Thanks in advance for the schematics! Jose... Thanks so much for your input! I never thought about simply loosening the sump to draw past the threads. Side note... I love these message boards and the people on them. It started for me with performance tuning my diesel truck and now with my "new" airplane. I thank each and every one of you for taking the time to share your experiences and knowledge! Matt Sent from my iPad using Tapatalk

Ok, I'm sure you guys are getting tired of hearing from me, but I love the information I glean from automotive and now aircraft forums. The brakes definitely are "weak." Although I would not want to, I doubt I could lock them up if I had to. Think Piper Cub. To me, a long time gear head, they feel like they need to be bled. They feel spongy and weak. I have also heard glazed pads will do much the same thing. I don't tend to need the brakes much, but it would be nice if I do need them. Thoughts? Sent from my iPad using Tapatalk

Thanks everyone! I am reasonably sure it is water that has settled around the sump and froze. We had some cold days, followed by 45+ followed by 9 degrees. Is this winter EVER going to end? Every time I have sumped the fuel In the warm weather I get some measure of water. It is too coincidental that this problem showed up as the temp took a drastic drop overnight. I am flying a trip for work right now, so I will find out Thursday if frozen water is the problem. Turbo... Thanks for your input! If the warm weather does not solve the problem, I will go this route. Hank... Yes, I will be extremely cautious. Marauder... Yes, I would love the schematics! I still have to find the problem. I shouldn't have to pull the gear warning horn breaker to fly at night. I know the problem is the nav light dimming relay, I just need to find it. Thank you! I looked in the tanks pretty close on the pre-buy and saw nothing floating in the fuel. This was the main thing I was looking for when I was looking at RVs as well. Also, I didn't find anything about top coating the sealant in the tanks in the the logbooks. I have to assume it has not been done. The airplane has less than 1700 hours on it. Take care! Sent from my iPad using Tapatalk

Great Sent from my iPad using Tapatalk

Black specs.. No. Below freezing... Yes. Well below, preceded by a couple of warm days. Water (ice) was my thought as well. It is above freezing this week so I will see on Thursday. Thanks for the response! Sent from my iPad using Tapatalk

Hey guys... Pulled the plane out yesterday, tried to sump the left tank and close to nothing came out. The valve opens, I can feel it, but very little comes out. Clearly there is an obstruction in the small holes in the sump. Worked fine the day before. Any ideas on how to clear it? Thanks! Sent from my iPad using Tapatalk

Ok. I found the problem. With the nav lights on, the gear down light extinguishes. I am assuming with the nav lights on, the gear down light has a resistor added to the circuit to dim it. I am thinking that might be bad. Anyway, with the nav lights off, it works just fine. Sent from my iPad using Tapatalk

No. Two lights. "Unsafe". And "gear down". They are not the iris type. Sent from my iPad using Tapatalk

Thanks so much! Sent from my iPad using Tapatalk

Found it. 22-1286 Sent from my iPad using Tapatalk

I will get you the S/N tomorrow evening. Thought I had it with me, but I don't. Sent from my iPad using Tapatalk

I would LOVE the schematics. Thank you! I will check that for sure. Sent from my iPad using Tapatalk

Ok. Thanks for the quick reply and the information. I will let you know how it turns out. It would be nice if it was just bulbs, but I am rarely that lucky. Sent from my iPad using Tapatalk

Do you know if there is a way to clean the contacts in this switch? Sent from my iPad using Tapatalk

Excellent! Thanks! Sent from my iPad using Tapatalk

Marauder... Thanks for the information! I did not know it would trip the horn at idle power. I don't remember it doing that when I bought it... Of course the gear down light was working then. Come to think of it, I don't think I swapped both bulbs, just one. It would be odd, but maybe the light itself completes the warning circuit. Somebody mentioned something about the nav lights having an effect on that light. I believe I had them on this morning while doing the test. I am now wondering if that nav relay is somehow affecting the system. Thanks again for your help! Sent from my iPad using Tapatalk

Dave, thanks for the quick reply. I did think about that and swapped the bulbs from the unsafe indicator with luck. If that was the case, why would the gear horn sound with the test? I think there is probably a continuity test of sorts with that system. Thoughts? Sent from my iPad using Tapatalk

Hey guys (and gals).... I very recently bought a 75 M20F. It is very low time but has sat for a while. Obviously there will be little issues with a 40 year old plane, but I don't care. She is the fulfillment of a lifelong dream. Anyway... I need your help. Went flying and wrung her out a little, testing the low speed envelope, did about five touch and go's and returned her to the hanger. This morning, I pulled her out and found the green gear down light not working. It would not test with the press to test and the gear horn sounded. The "unsafe" light operates normally. Everything operated normally except the gear down light. Of course, the gear horn sounded with throttle retardation. The manual indicator in the floor showed down and locked and there was no problems with the landing. I am pretty sharp with electronics and have a maintenance manual coming. I have learned that the indicator half of the down limit switch will fail on occasion. Does sound like a likely culprit? The plane sat for 14 years after the owner died and I am sure there is some grime in the switch. Is it possible to clean the contacts with contact cleaner? Thanks in advance for your ideas!