Strobe light troubleshooting

[VA FLYER]

Wingtip strobes work fine, tail does not work at all. Checking line power to the tail gave a steady high voltage reading, with no pulse action. Strobe tube is blackened, which I think means it's probably failed. The line voltage seems strange and I don't want to just replace a light tube if the line voltage is wrong. Unit is a Whelan A625-D. The cover and housing are fine, so can I just replace the A625-D flash assembly with a 627 flash tube assembly? Much less $$$.

[LANCECASPER]

6 minutes ago, VA FLYER said:

Wingtip strobes work fine, tail does not work at all. Checking line power to the tail gave a steady high voltage reading, with no pulse action. Strobe tube is blackened, which I think means it's probably failed. The line voltage seems strange and I don't want to just replace a light tube if the line voltage is wrong. Unit is a Whelan A625-D. The cover and housing are fine, so can I just replace the A625-D flash assembly with a 627 flash tube assembly? Much less $$$.

You should have a strobe power box for the tail strobe screwed on to the inside of an inspection plate under the tail on the pilot's side. Be careful working with the high voltage coming out of the strobe power supplies.

[VA FLYER]

Lancecasper,

Thanks. I did not realize there was a separate power supply just for the tail strobe. 

 

[N201MKTurbo]

I would remove the tail strobe tube and try it on one of the wing power supplies. And while you are at it, try the wing tube on the tail PS. This will tell you if it is the power supply or the tube.

It is usually the tube.

The black on the inside is the metal from the end electrodes. They degrade just like your spark plugs, but instead of the metal going out the exhaust, it collects on the inside of the flash tubes. It doesn’t necessarily mean they are bad, but when the metal deposits short the two electrodes together, it cannot ionize the gas and it won’t flash any more.

[VA FLYER]

Turbo,

Thanks, we'll do that but couldn't get to it today.

[Fly Boomer]

2 hours ago, VA FLYER said:

Turbo,

Thanks, we'll do that but couldn't get to it today.

If it turns out to be the power supply, I have had some luck "resurrecting" these by running at half voltage and, if they flash, moving the voltage up in increments over the course of several hours until you get to whatever voltage your airplane uses.  I think the caps don't like being unused for any length of time, and sometimes they can be tickled back to life.  I have read that they should be run for 15 minutes every week, or some similarly surprising schedule.

[Rick Junkin]

@VA FLYER If it turns out to be the power supply and you need one, I have one I removed from my Bravo when I installed LEDs. It will probably fit in your airplane (probably same part number). Send me a PM if you need one and we'll get it arranged.

Cheers,
Junkman

[Pinecone]

I have three strobe power supplies for 28 volt from replacing mine with LED