Question about Strobes

lr172 · #1 08-25-2016, 06:19 PM

During my annual, I found that my starboard strobe only flashed occasionally. I found a defective crimp from the factory and the repair seemed to fix the issue. I checked again today and found that sometimes it flashes once and sometimes twice, as it's supposed to, and sometimes it completely misses a cycle. I think the power supply is slowly dying, but wanted to see if anyone with experience thought this could possibly be the bulb.

Appreciate the help.

Larry

V111Pilot · #2 08-26-2016, 07:06 AM

My experience is that it is most likely not the bulb. Check all of the crimp connections (if you have any), then it is probably the power supply.
FYI- I bought a Whelen strobe power supply on ebay used for $20 and it flashes brighter than the "aviation" one did before.

LettersFromFlyoverCountry · #3 08-26-2016, 09:46 AM

Yeah, if it's a Whelen, I'll bet there's a bad connection.

When I first started playing with my Comet 6 setup, I was getting an irregular pattern; even sent the unit back to Connecticut to get fixed (they sent it back and said it was fine).

What I found was if all three wires weren't plugged in, the system would only fire the wings sporadically instead of alternately with the tail. Plug in all three, and it was fine.

Not saying that's your problem-- this was 8 years ago.

Toobuilder · #4 08-26-2016, 07:01 PM

Every time I run into this it turns out to be the flash tube. Plug a known good one into the power supply and confirm (just switch plugs at the power supply).

lr172 · #5 08-26-2016, 09:55 PM

Thanks for the input here. Today, I took the PS and bulb home, thinking that I would tear the PS apart and maybe replace the caps. I set it up on the bench and it works perfectly

So, I installed it back on the plane and same old problem persists; even tried a new ground connection. I tried jiggling different wires and got the most involvement with the feed wire from the conduit. Tomorrow I will get under the panel to check the connection at the switch and make new connections in the floor.

Stay tuned.

Larry

lr172 · #6 08-29-2016, 08:45 AM

I tightened up the fastons on the the switch and re-crimped the connection to the problematic strobe. It seemed to work at about 95%. It never missed a flash, but there was an occasional single flash instead of a double flash.

The next day, I tested again and got a decent amount of single flashes instead of double flashes. Also, during a flight that day I got some very occasional noise in my headset and I have never had noise before.

I think that I may do some more isolation to be sure it is not wiring and a little more bench testing. It feels like a Power supply issue, but the fact that I could improve things by playing with wiring leaves me a bit suspect of the wiring. The Port side is completely without issue.

Larry

lr172 · #7 08-30-2016, 04:36 PM

I confirmed all of the wiring - no improvement. Took it off and back to the bench - same problem on the bench now. Pulled the cover off the power supply to see if I could find a problem and possibly replace the cap. Upon inspection, I noticed a black mark on the cover. That mark lined up with a transistor (the LM317 type with the grounded metal at the top). It was installed at a bit of an angle and was touching the cover occasionally it appeared. Bent it back away from the cover, reinstalled on the plane and now it works perfectly.

So much for QA at Aeroflash.

Larry