VP-X tripping on Skyview new install

[wilkersk]

I have a new install Skyview classic: two 7" displays, dual ADAHARS, GPS 2020, EMS, SV-COM-T25, SV-TXPDR-261, SV-AP-SERVOs (pitch&roll). Wiring has been verified (rung-out plug to plug). But, when I power it on VP-X trips the COM, TXPDR and AP. I went throught the configurator app on the VP-X to make sure amps and status were correct. I'm at a loss. Anyone else with this setup have a suggestion?

 

[SV_Classic]

I'm not an avionics tech but tripping circuit breakers would motivate me to check the wire runs again, even if it's the fourth or fifth time. Even if the wire and pin placements are correct, maybe you have stray wires inside the connectors causing short circuits? Maybe a pin backed out and it's in there shorting other stuff out?

If you suspect the VP-X is causing it, maybe wire a real circuit breaker into the circuit to see if it also pops?

 

[jakej]

IMO the issue is in the wiring somewhere, I’ve done a lot of VPX installs & never had a fault in the unit itself. The current software version has been in place for ~ 10 years so that shows it’s ‘maturity’.
I’d unplug all the devices connected, except for 1 x screen, & plug them in again 1 at a time to to ‘see’ where the fault may be.

 

[CanardMulti]

A couple of years ago I completed a substantial IFR upgrade to my homebuilt, which included building over a dozen harnesses from scratch. Even a little bit of smoke on first power up would have been a painfully expensive lesson, so I became super focused on checking for all manner of harness deficiencies. I fabricated test pins onto discreet wires to allow connection to individual pins in each plug one at a time, checking that each and every pin was talking to the correct pin on the other end of the harness, was NOT shorted to ground, and was NOT shorted to any other pin in the harness. Each pin was checked at least 3 times. I kept a check off log of each harness' wire pair. When all tests were complete, every pin-pair on every harness wiring schedule had 3 check marks. Everything worked on first power up. And no smoke.

 

[wilkersk]

Oh believe me, I am going over the wiring again and again. I'm sure it'll end up being some simple-stupid thing I've overlooked. I was an avionics tech-flight line troubleshooter years ago, plus 5 years in avionics/electrical at a major repair depot, FCC GROL and HAM operator. So, I do know the drill. But, I'm just curious to know if maybe theres some quirk in the setup process I'm not aware of.

 

[jakej]

I forgot to add- I always check power & grounds first before powering anything up. We’re all cable of having a ‘bad day’, don’t ask how I know as it happened a long time ago & I‘ve done ~ 50 installs since, certainly made me more careful since. Serial & Arinc data cabling is not normally an issue.
I’ll PM you.

 

[SV_Classic]

checking that each and every pin was talking to the correct pin on the other end of the harness, was NOT shorted to ground, and was NOT shorted to any other pin in the harness

that pretty much sums it up, continuity between correct pins, not shorted to ground and not shorted to another pin. I never really thought about it that way but it makes sense!

@wilkersk , please let us know what you found when you've got it fixed. I actually pulled the VP-X from the plane I'm working on and installed circuit breakers, bus bars and switches. I understand they're reliable but the install was too much of a mess to save and I wanted everything up on the panel. That first flip of the switch must be a nail biter!