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Troubleshoot Whelen Strobe Controller HDACF 14/28

Tcheairs

Well Known Member
I have a real mystery on my hands. As discussed previously in another post. Strobes not working from the panel

1. I cut the wires from the panel (+ and -) near the controller and connected the strobe controller DIRECT to my cigarette lighter outlet with a test harness I made, turned on the battery switch and all 3 strobes fired beautifully.

2. Then I re-checked the voltage at the (cut wires + and -) which come from the panel and ordinarily supply power to the controller. Turned strobe switch on and got 12.5v steady on the multimeter. again, that's using the + and - from the panel.

3.Then tried using 12v power from the panel switch and grounding the ground wire from the strobe controller to the frame (sharing the GDL 82 ground). No voltage on the multimeter..tried several other nylon lock nuts in the back which I'm sure are grounded and still no voltage

4. Rewired the system using the original wires and no strobes

This makes no sense whatsoever..any ideas?

Thanks
 
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Seems to me that some resistance has developed along the circuit. Measured at no load with just your high-impedance multimeter, everything seems fine.

However, as soon as there is a real load, the voltage across the load drops to near nothing as it is lost at the unwanted resistance.

Connect your load (the strobe supply or just an automotive lightbulb from an indicator or brake light) to the cut wires. Turn on the strobes switch and work along all connections (positive as well as ground connection) in the circuit until you find the one where the voltage drop occurs. Use your multimeter with long leads and perhaps a pair of helping hands and measure voltage working forward from one connecting point to another. Once you found the section with the voltage drop, try narrowing it down until you found the bad contact or connection.

Hoping that helps
 
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Yep, only checked voltage with no load on the system. Is it possible that a weak cb or switch could cause this condition? That would be the easiest place to start. Jump the cb first, then the switch (which is a PITA to get at above the throttle Prop and mixture controls)
 
it is possible for the switch contacts to oxidize (typically on a cheapish part), but usually that will make the switch intermittent.
 
Yep, only checked voltage with no load on the system. Is it possible that a weak cb or switch could cause this condition? That would be the easiest place to start. Jump the cb first, then the switch (which is a PITA to get at above the throttle Prop and mixture controls)

Short answer - yes.

Now, turn the strobes on (established a load demand), then check voltage upstream at each wire intersection. Both sides of the switch, the CB, back to the power source. Also the ground, but I would do the 12v side first.

Sorry - no pun intended!!
 
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