Whelen Strobe Power Supply

[Steve65E-NC]

Today as we annualed my 65E we discovered no Port or Tail Strobe except a single flash on system power down.  The Starboard worked initially and then joined the others.  Suspect common cause.    The single, fuselage mounted,  Whelen Power Supply is an A413A HDA-DF-14.  Whelen says they no longer make or repair this  unit.  They suggest replace with a CF-14.  Looks like close to a thousand $ to replace.  Probably just Capacitors.  Any suggestions on someone to rebuild/repair.  A type and source for capacitors.  Or a source for a servicable unit.

[Oscar Avalle]

I ended up replacing mine...

[flyingvee201]

Just PM'd you.

 

 

Vic

[KSMooniac]

I might have a serviceable unit as well from my salvage J model... I don't have the part number handy but can go get it tomorrow.

[N201MKTurbo]

I would try the strobe tubes before I condemned the power supply.

[Steve65E-NC]

    I read about a Whelen Strobe Check unit that Aircraft Spruce sells for about $175.00.  It apparently allows check of supply and tubes.  Anyone have one that they want to sell, rent, or loan. 

    Apparently bad tubes may crash a good supply so all need testing.

 

Steve65E-NC

[jetdriven]

Open it up and replace the capacitors. Another thing to look at is eBay. 

[bumper]

I have a 3 output Whelen Comet Flash removed from my '05 Husky when upgrading to all LED's. It's looking for a new home, $225 includes shipping to lower 48 (or 55 if you go by BO's numbers).

 

Your strobe power supply can also be tested using "regular " test equipment. The capacitors should charge up to over 400 volts DC, so this can be measured and checked with a DVM (digital volt meter). For the high voltage trigger, they "used to" use a simple relaxation oscillator that worked by charging up a smaller capacitor in parallel with a small neon lamp, when the lamp reached it's ionization voltage, it would discharge the cap through a coil, repeat. Now they probably use a solid state oscillator for that. In any case, the trigger or excitation voltage will typically be around 6KV. You can use a cheapo electric fence test meter to measure that voltage (a neon lamp type spark plug ignition tester might work too, though won't tell you if the trigger is weak).

 

Note that the 400 volts DC is way more dangerous due to it's higher  current capability than the 6 thousand volt trigger -  which can still knock your socks off but is kinda like getting zapped by an electric fence charger. In any case, don't mess with the power supply 'less you know what your doing. Before opening up the strobe supply, remove DC power (duh), and after removing cover, directly short out the big capacitors with insulated screw driver, test lead etc, just in case they are holding a charge.

 

BTW, I agree with testing the strobe tubes first. They do wear out, get weak, and exhibit the behavior that you are seeing. Use a known good strobe tube to see if each output of your supply is working. I have never heard nor experienced strobe supply damage by powering it without strobe tubes attached. Caps charge up to max - - they're designed for that, no big deal.

 

bumper

[Steve65E-NC]

Thanks all.  Since all three tubes are now not working.  How do I best test them??  Any way to do it with a DVM?  One does show some black inside the tube is that a give away for a failed tube??

 

Steve65E-NC

[jetdriven]

The ends of the strobe tubes turn gray then black and that's a sign of aging. However as long as they flash they are OK. If the whole tube is dark it may be bad. Try to borrow a known good one and plug it in to test.

[N201MKTurbo]

Buy a new strobe tube and plug it into the connectors on the power supply. It should flash well in all three positions. The Aeroflash tubes work just fine and are half the price of the Whelen. Neither has any markings so nobody will be able to tell which tube you have.

 

When the power supply gets weak it will usually flash slower because it is taking longer to charge the caps.

[Steve65E-NC]

THE SOLUTION:  Before buying new supply or tubes, I called an xham xmooneyowner for his thoughts.  He said that since all three flashed on shut down I might want to check the switch/circuit breaker before spending big bucks.  I think the flashes indicate both high voltages available, at least for that instant.  

 

   First with master off I checked the switch on resistance with probes to the screws and found about 4 ohms.  Next, with Master and Strobe turned on I used a short wire to jumper across the Strobe switch in the cockpit.  I saw some sparks and knew right then I was onto something.  Sure enough, all three strobes on and working.

 

    The Strobe Switch/cb was marked as 10 amp.  My I/A had plenty of 20 amp, no ten amp.  Holding the switch vertical I made multiple applications of contact cleaner and cycled the switch.  It seemed to loosen up.  Sure enough on reinstall, after cleaning all switch connections, it worked fine. 

 

   So the peanut butter does not alway hit the floor first.

 

Thanks to all who offered solutions and equipment.

 

Steve

 

PS: on to removing a couple of vertical exhaust stacks with small seam leaks.  I was surprised at the hidden erosion, right next to the head,  of some of the bolts at the ball joints.  Will probably just replace all those bolts.   

[Awqward]

My tail strobe light failed and I replaced the flash tube....only to discover that it was the power supply (Whelen 490ATS)... I have managed to track down a salvage power supply and it is on the way....but in the course of my research I came across the Whelen OR500 http://www.whelen.com/aviation/product.php?head_id=11&prod_id=162 .... They are apparently designed to replace the old units and do not require the power supply....BUT It specifically says FAA/TSO approved but no PMA or STC....what does that mean? Does anyone have these units installed on their Mooney?