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I just found these toggle switches with gold contacts. They are the same form/fit/function as the ones I currently have. I'm ordering a few. Braun 31787KS
stretchersrus.com
Might have already mentioned this but you could change switches in the VPX programming. SWAP switch 3 with another switch that is wired to the VPX (landing) and then swap caps so you don't get confused. Go in and change all switch 3's to whatever the landing power was on and set landing to switch 3. That would tell you if you might have bad avionics switch or associated wiring or pin that's on switch 3. It's a 5-minute job. If you have not had an issue with "always on" maybe it is a bad switch, wiring or pin?
Seems to happen a lot. Pressing the button that says on will turn it off.
That is a good plan for testing with a different switch and wire.Might have already mentioned this but you could change switches in the VPX programming. SWAP switch 3 with another switch that is wired to the VPX (landing) and then swap caps so you don't get confused. Go in and change all switch 3's to whatever the landing power was on and set landing to switch 3. That would tell you if you might have bad avionics switch or associated wiring or pin that's on switch 3. It's a 5-minute job. If you have not had an issue with "always on" maybe it is a bad switch, wiring or pin?
Also, if that's an ACK-04 ELT appears its mounted upside down.
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Good luck, I know can be frustrating.
BTW, although gold contacts might be better Stein has supplied thousands of silver or silver tin-oxide contact switches for VPX applications (including 2 of my airframes) and to date have never seen or heard of an issue with silver contacts but when measuring in PPM you could have an outlier. Going to a different switch might tell you something even if it has an unreliable silver contact.
look for switches rated for .4 amps. those are usually the gold ones.
this has been my experience as well. clearly gold is better, but very low current draws tend not to harm the silver ones and therefore often provide a good low resistance over a long period of time.BTW, although gold contacts might be better Stein has supplied thousands of silver or silver tin-oxide contact switches for VPX applications (including 2 of my airframes) and to date have never seen or heard of an issue with silver contacts but when measuring in PPM you could have an outlier. Going to a different switch might tell you something even if it has an unreliable silver contact.
The VPX page on the G3X will allow you to enable or disable a circuit regardless of the state of any external rocker switch slaved to that circuit. So lets say your AV Master switch craps out, you can just re-enable the circuit from that page.
VPX per there instructions switches carry very little actual loads per awg wire specs:
Wow, I leave for a few days and there are pages more of replies. Great to see the RV community pitching in to help!
I'll have to respectfully disagree with Walt on this one. This was hotly debated on VAF 18 years ago when the VP systems first came out, and there will always be people who want the latest and those who are only comfortable with traditional stuff.
I am currently bypassing it and it is working fine but only one flight in. I will be looking into that switch.
Some of us like more data, some don't. Some prefer steam gauges, some not. It's your choice..........Personally, I like systems that can tell me amp draw per circuit. You may not. Easier to troubleshoot an issue, just not for you to try and understand "complicating things" it seems.
The really great thing about building your own plane is you can build it anyway you want!
Its risk vs reward in all of these decisions and you are correct that we will all weigh each side of the scale differently. What if i offered you fly by wire. We ditch the throttle cable and replace with sensor and servo motor, so now you can see down to a tenth of an inch how far in your throttle is. Are you interested? Will you take the risk of a failed sensor preventing you from going to idle as you land? What about electronically activated brakes where you can display exactly how far the pedal is depressed instead of the old outdated hydraulic system that provides no data. Will you accept the risk that a blown capacitor on the board prevents you from stopping at the end of the runway? Advanced computer controls is cool and offers more data, but cones at a non zero reliability hit. Simple mechanical systems generally offer greater reliability at the cost of more limited capabilities. I really struggle to see how an advanced computerized power distribution unit is just as reliable as a circuit breaker and a switch. Thats like saying a typewriter is just as likely to reboot itself as a computer.
I do like more information, but from a risk analysis perspective the information it gives me isn’t worth the new failure modes.
Interesting. How did you determine that the alternator was producing ripple/voltage swings? Was this visible in the EFIS graphs, or did it require an oscilloscope? Here's 2 mins of data from my EFIS showing current and voltage - I think it looks strange, but has not caused any operational issues....
The Vpx shows the power going off. I am using a different internal buss for each unit. Well using all 3. The fault is turned off. When it does the multiple cycles if I shut it off on the Vpx it comes back on on its own.
If there was thousands of these fly by wire systems out there and 10+ years experience it’s possible but it’s about understanding the risk vs reward as many have said. I’d say to be number one with said system no not worth it. But let’s not be creating a DARPA project and use that as rational it’s to complicated.
I see a similar pattern (drifts only oscillate < .4 volts though) on my GRT voltage sense input; There is a bunch of noise or something in there system and admit this is a byproduct; Something about the video driver power supply. The EIS and the G3X in my other plane are very stable. That said, your graph would scare the crap out of me! Suggest getting readings via a trusted meter. If you are actually seeing voltage swings of 6 volts, I promise you it won't be symptom free for much longer.
I'm getting more confident its your rocker switch.
Yet anyone who drives a newer vehicle has exactly what you describe with electronic throttle control and brakes and steering…and they are driving far more often than flying. Are you willing to accept a fault in any one of those systems while you are going 70 in the highway in traffic?
How do you explain the majority of VPX users that have experienced zero issues? Yet the OP has had TWO failures. If it was a systemic problem, statistically you would have others having the same problem across the field of users.
Agreed. I say let's stay on topic and help the op solve his problem ... no minds are being changed here ... there is a level of risk we all accept.
I had very similar symptoms with my VPX. Audio panel and Autopilot each rebooting randomly, but only very occasionally.
Yep but not everyone believes that.
It might be more of an issue than we know. I just was in contact with yet another person last night that had the same issue as me but more severe with the cycling. Not everyone posts on VAF and when you talk to VPX it’s the first they heard about it when you have a problem. He solved his with a new master relay. Then many flight hours later it happened again and a new relay fixed it. I am planning a more permanent fix. Clearly the system is sensitive on some installs.
Or less than you think. But definitely not "clearly the system is sensitive on some installs", there's no data to support this claim or even if the op and "another person" are having the same issue or that either issue is VPX related.
Yes, I accept that fault. And yes, I have troubleshoot and replaced pedal sensors that failed as well as electronically actuated throttle bodies that caused erratic performance. Consider all of Toyotas problems / lawsuits related to uncommanded throttle application (unclear whether the computer went haywire or the driver). The most serious offender is the crankshaft position sensor; A single $40 variable reluctor, prone to heat failure, that the engine is 100% dependant upon. Seen it abruptly stop the engine in all manners of unsafe conditions.
sorry, will stop now.
Hi Larry, voltage is on the right scale - swings are only about 0.2 volts. The big jumps are current through the hall effect sensor, which is on the B-lead just after the alternator.
.2 is nothing and likely just imprecision in the EMS. I would throw a meter on it to confirm though. While .2 is not a big deal, if it is happening, it is abnormal and could be a sign of something not right. Alternators are generally pretty stable outside of periods of changing demand. The PP has a bunch of issues with the stator that can cause symptoms like this and this could be an early warning sign.
Uhm...the stator? The "WYE" windings in the lam-stack that don't move? Please expand upon this...
Update: Recently I've had issues with my landing light. I replaced the switch, and it worked for a while. Today it was flakey again. When I checked the ground at the switch it was 25 k-ohms. At the other end of the wire is a spade terminal to a ground block. I removed the wire and plugged it into another spade and the resistance to ground at the switch went down to 0.0 ohms. I checked the grounds on all the other switches, and they were all 0.0-0.2 ohms. When I had problems with the autopilot a couple months ago, I replaced the switch and that appears to have solved the problem, but I can't be 100% sure if it was the switch or ground. If I have problems in the future, I'll look at the ground connections before I do anything else. Intermittent problems sure are frustrating. Since I can bi-pass the mechanical switches by using the soft switches in the MFD I'm not too worried.
That could be true; I'm interested in what the difference is that is causing the problem.
Agreed. I would really like to know what is causing the problem, too.
I did go through them in the spring. I think that was after you had told me then to check them to rule that out. I will look again though.
