Piper post lights- Oil Vac Alt and the GE330 bulb

Discussion in 'Maintenance Bay' started by Unit74, Dec 8, 2015.

  1. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    So I have some LED replacement bulbs I just got in from Allied Electronics. They are the GE330 equivalent and miced out almost identical in base/flange. They are center post positives.

    None of them worked in the plane. Thinking it was low voltage, I fired up the plane to achieve operation volts. No dice.

    Bench tested on 12v power supply and they work fine. What I didn't have was a volt meter to test the post light sockets.

    Does anyone know if Piper post lights are set up as center post negative? This would be a 14v 1979 Archer. It's the only logical reason these lights are not working. A moderate search on the interwebz resulted in no negative center post GE330 bulbs.

    Scratching my head......
     
  2. will44s

    will44s Pre-Flight

    Joined:
    Nov 3, 2012
    Messages:
    47
    Location:
    Wy
    Display Name:

    Display name:
    Notch 8
    Not sure about Piper, but on turbine aircraft that I've worked on if the bulbs weren't exact in all dimensions the posts wouldn't put pressure on the bulbs causing poor or no contact.
     
  3. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    Pressure on the bulbs was good. They were pressed in and slightly difficult to get out from the "grip" on the sockets. Distance from the center post to flange was identical, so I know it has to be bottoming out and making contact.
     
  4. will44s

    will44s Pre-Flight

    Joined:
    Nov 3, 2012
    Messages:
    47
    Location:
    Wy
    Display Name:

    Display name:
    Notch 8
    Don't want to send you down the wrong rabbit hole, but some post types use the hood for pressure, if the glass in the bulb is a different length it won't work, you can try leaving the hood off a couple and push in with your fingers while powered up to see if that's it. I have never heard of a negative center post and since they work on the bench not sure were else to go with it, sorry.
     
  5. ahkahn

    ahkahn Line Up and Wait

    Joined:
    Oct 1, 2014
    Messages:
    872
    Location:
    Chicago, IL
    Display Name:

    Display name:
    92E
    I had the same problem when I attempted to swap out the bulbs for the gear lights and those same annunciator lights. I gave up...
     
  6. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    Have you tried a meter on the socket? How about jumper leads to the bulb so you can swap polarity for the test?
     
  7. bnt83

    bnt83 Final Approach PoA Supporter

    Joined:
    Dec 31, 2012
    Messages:
    8,979
    Location:
    Lincoln NE
    Display Name:

    Display name:
    Brian
    Non-dimmable led bulb into dimmer circuits?
     
  8. SCCutler

    SCCutler Administrator Management Council Member PoA Supporter

    Joined:
    Feb 27, 2005
    Messages:
    16,866
    Location:
    Dallas
    Display Name:

    Display name:
    Spike Cutler
    Assuming you're actually getting good contact, this is my first vote as well. Many LEDs do not dim worth snot.

    I have used LED replacements in my gear up/down lights (the good, old-fashioned press-to-test indicators with the adjustable iris and screw-out carrier) with good effect. Not sure whether I've placed any in post lights or not, and I can't test until my poor bird is reassembled after engine install.
     
  9. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    Even though they don't dim worth snot, they typically will still work but 'pulse' until the power gets really low. If you have close to the right voltage and they don't come on, typically the polarity is reversed, ot the bump is junk. Depending on the brand, I typically find 1%-5% are dead in the box or die within half an hour. If they make it through that, I haven't replaced one yet.
     
    Last edited: Dec 9, 2015
  10. AKBill

    AKBill En-Route

    Joined:
    Nov 29, 2014
    Messages:
    2,759
    Location:
    Juneau, AK
    Display Name:

    Display name:
    AKBill
    I overhauled a piece of miming equipment and installed LED lights in the engines stop engine light (SEL) and check engine light (CEL) indicators.

    When running the CEL would glow dimly, found the engine control module (ECM) output a very small amount of current in the milliamp scale on this circuit when operating normally.

    I installed a 200 ohm resistor inline that corrected the problem. These lights work with very little current.

    My guess would be socket is not compatible with the bulb, or you have no power to socket which is unlikely but should be checked out.
     
  11. Tom-D

    Tom-D Taxi to Parking PoA Supporter

    Joined:
    Feb 23, 2005
    Messages:
    32,874
    Display Name:

    Display name:
    Tom-D
    I'd check voltage of the socket.

    bet it's not 12-14 volts.
     
  12. SkyDog58

    SkyDog58 Touchdown! Greaser! PoA Supporter

    Joined:
    Jun 11, 2015
    Messages:
    13,572
    Location:
    My own special place.
    Display Name:

    Display name:
    Canis Non Grata
    I've seen the info on some LED bulbs have a note that says they are not intended for post lights.
     
  13. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    I have power as all the lights are working on incandescent 330s. I'll have to put a meter on it and see what's up.
     
  14. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    Put a meter on it and promptly shorted it out. Now none of my oil vac alt lights work. What the hell did I do now? No breakers popped.
     
  15. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    Spin your dimmer rheostat dial. You may have shorted with the meter and popped something there as well.
     
  16. Clark1961

    Clark1961 Touchdown! Greaser!

    Joined:
    Jun 7, 2008
    Messages:
    17,746
    Display Name:

    Display name:
    Display name:
    On a Piper? Prolly fried the other lights. It happens...
     
  17. AKBill

    AKBill En-Route

    Joined:
    Nov 29, 2014
    Messages:
    2,759
    Location:
    Juneau, AK
    Display Name:

    Display name:
    AKBill
    Do you have a wiring schematic? If so you can find what powers that circuit a fuse or circuit breaker.

    My plane has fuses as well as circuit breakers maybe you blew a fuse.
     
  18. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    The dimmers all worked good. No other lights affected. Pulled the plastic cover and it looks like the damn glareshield has to come off to access the post lights. I'll see if I can't crawl back up in there and look for a fuse, but I don't think I can. The gyros are in the way.
     
  19. taters

    taters Pattern Altitude

    Joined:
    Jun 29, 2007
    Messages:
    1,712
    Display Name:

    Display name:
    Taters
    same when I tried it in the overhead dome light...the only interior lights that DID work when switched with LED were the panel lights on a 76 PA28
     
  20. Dan Thomas

    Dan Thomas Final Approach

    Joined:
    Jun 16, 2008
    Messages:
    6,283
    Display Name:

    Display name:
    Dan Thomas
    Bet you cooked the dimmer transistor.
     
  21. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    Dimmer is working on the panel lights. I don't think it's that unless you have an idea why it would only affect the three oil vac alt lights.
     
  22. AKBill

    AKBill En-Route

    Joined:
    Nov 29, 2014
    Messages:
    2,759
    Location:
    Juneau, AK
    Display Name:

    Display name:
    AKBill
    Cycle the breakers again, some times they look like they are set but are really tripped.

    The fuses I mentioned in my plane are located on the fuse panel with the other breakers not behind the instrument panel.

    Find a schematic for your plane that shows the routing of power to the lights. That way you can check power from source to lights.

    Maybe your A&P/IA can help you with this. Good luck.
     
  23. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    Yea... MX has the keys. It needs a vac filter, oil change and ELT batt change so he is gonna fix it too while its down for that.


    Note to self..... Quit trying to upgrade ****. It either costs a lot, or I F- something up and it costs even more.
     
  24. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    :lol: There is truth to that, but it's more accurate to say, 'don't upgrade half way/on the cheap, do it right the first time so you enjoy the result'. That is how you get the most value out of your aviation $$$, by enjoying it.

    Now that you figured out this post light thing isn't where it's at, take a look at the Nulites. http://www.aircraftspruce.com/catalog/elpages/nulite.php

    These things ROCK. Put them in the 310, looked at what they cost on the bill, laughed and said, "best money I ever spent in aviation."

    image.jpeg
     
  25. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    You know what's funny....



    My shop has a faux sign over one of the desks with hourly rates. It says $50/hr, $75/hr if you watch and $100/hr if you worked on it first.


    Pretty sure I'm in the $100/hr plan right now.
     
  26. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    You believe it to be a 'faux sign' why?:dunno::rofl: