TROUBLE-SHOOTING PROCEDURES FOR AVIATION
|THE POWER SUPPLY IS A HIGH VOLTAGE DEVICE. LET THE POWER SUPPLY BLEED DOWN FOR 10 MINUTES AFTER TURNING OFF POWER BEFORE HANDLING.|
|WARNING: Reverse polarity of the input power, for just an instant, will permanently damage the power supply. This damage is sometimes not immediately apparent, but will cause failure later on.|
A normal operating power supply emits an audible tone. If there is no sound emitted, investigate as follows:
1. Determine that there is a proper input voltage at the power supply. If this test is positive go to step 2.
2. Clear all possible shorts at the power supply by disconnecting the output cables from the power supply and connect an operating strobe light head assembly. Then apply the required voltage to the power supply input. If this application proves positive the power supply is in working condition, and the problem may be with the interconnecting cables.
3. A quick check of a strobe light system is to listen to the flash tube by using a paper cup as a stethoscope. If the power supply and trigger transformer are good, you will hear the trigger spark snap, like spark plug sparks.
NOTE: Aeroflash does not recommend attempting to repair power supplies in the field. It is recommended to take advantage of our Repair Service. We offer a one-year warranty on rebuilt power supplies. Call Aeroflash for details.
If pins 1 and 3 are reversed, or if there is a short between pins 1 and 2 of the interconnecting cable, the power supply will be rendered non-operable until the short is cleared. A short of this type will not cause any permanent damage to the power supply. However, a discharge of the condenser across pin 1 and pin 3 will destroy the trigger circuit in the power supply.
1. Check for continuity between the connectors of each interconnecting cable:
Pin 1 to pin 1 (red wire = anode)
Pin 2 to pin 2 (black wire = flash tube ground)
Pin 3 to pin 3 (white wire = trigger).
2. Check for shorts.
NOTE: When pins 1 and 2, or pins 2 and 3 are reversed, the system will operate normally, but these conditions will cause early flash tube failure, and void the flash tube warranty.
1. They will become hard firing with age, or when exposed to a very high temperature. A hard firing tube will sometimes operate with the engine running, but will fail when operated on a low battery.
2. They can develop a leak through eggshelling of the glass, or a leak can develop around the seal of the wire to the glass. This is caused by the hot and cold cycling of normal operation of the system.
3. They can go into self?ionization (continuously glows a light blue), thus rendering the entire system non-operational until flash tube is replaced. This most likely occurs when the input voltage is highest. Turning the system off can check this. When turning the system back on, it generally will operate normally for a few flashes before going back into self-ionization.
4. Replace after 1000 hours of operation
Any of the above conditions requires flash tube replacement.
Aeroflash strobe light power supplies are designed with a low pass filter built in to keep R.F.I. and E.M.I. down to a minimum, however, sometimes there will be interference in the radios by the strobe light system. Most always, this is an installation problem, not a strobe light power supply problem.
The power supply should acquire its power from a low impedance source, such as the alternator or generator end of the electrical buss. Historically, the rotating beacon or strobe light circuit breaker is added on the electrical buss at the opposite end, with the radio in between the strobe breaker and the low impedance end of the electrical buss. Any noise generated by the power supply will be transmitted into the radio through the A+ input lead to the radio. Most of the new radio equipment manufactured today has inadequate input filtering, and any noise on the electrical buss is amplified in the radio and produced through the speaker and/or head phones loud and clear.
Two things can be done to alleviate the problem...
1. Connect the strobe light circuit breaker to the low impedance end of the electrical buss, using a 16-gauge jumper, as close to the battery as possible.
2. Install additional filtering in the radio A+ line, or provide an isolated A+ source for the radios by installing a filter choke in series with the radio input power lead and a filter adapter to ground and reference all radios to their filter. This will also improve the radio system from other line noises.
Frequently, the noise is not on the A+ lead but is conducted through the ground circuit. Alternator, electrical motor, fuel pumps and strobe light power supplies draw heavy current through the ground circuit of the aircraft's frame. Any voltage drop in the ground circuit between the battery ground and the radio ground can look like a signal to the radios. When the speaker, headphone and microphone use the aircraft's ground for return to the radios, one will always experience some interference. The amount of interference depends upon how much potential difference there is between the two ground points. By isolating the audio grounds from the airplane ground at the speaker, head phone and microphone junctions, and grounding the aforementioned with the radio at one central ground point, will eliminate the majority of all ground inducted radio noise.
Do not parallel any audio leads with any power lead supplying energy to a noise generator; (i.e.) alternator, electric motor or DC choppers such as inverters and strobe light power supplies.
The interconnecting cable between the power supply and the remote strobe light head assembly radiate very little, for the output circuit of the power supply is very low impedance. They can radiate RF like an antenna if the shield is not terminated to ground. The radiation of RF energy is reduced to a minimum by properly terminating the shield at one end or the other, generally the power supply end, but which ever proves the quietest ground. Do not terminate both ends.
When installing a strobe light system, provide a good ground and a low impedance source to the strobe light power supply. Eliminate ground loops in audio circuits by using a centrally located ground point for all audio grounds. If noise problems persist, and the procedures described have not cleared them up; please contact Aeroflash for assistance.
For more assistance, use our Contact Us page
or call 312-733-3513 Ext. 300 (M-F 6:00 AM to 2:30 PM CST)