TRANSPONDER REPAIRS    
            

                              FLIGHT CONTROL SERVICES FAA CRS#OFHR414L 

                        USE THE ORDER FORM LINK ABOVE TO ORDER SERVICE

              Updated JULY 2024

          TRANSPONDER RECERTIFICATION'S AND REPAIRS INCLUDE A FRESH ALIGNMENT AND LOGBOOK ENTRY FOR $195 PLUS SHIPPING
WE WILL BE CLOSED THE 3RD WEEK OF JULY AND TWO WEEKS LATE SEPTEMBER

Order service by clicking on the link. There are a few things you should know first:                        

You might want to try our It's simple and might point you towards a repair that could be handled by your local mechanic.

IF YOUR TRANSPONDER IS NOT WORKING IT MAY JUST NEED AN ALIGNMENT

A standard factory alignment procedure varies depending on the manufacture and unit. The text below in RED are the actual alignment points.

We always adjust the VOLTAGE REGULATOR first. Next to the receiver where we tune the LOCAL OSCILLATOR to center which has a sharp falloff so the position is critical. We then adjust the LOCAL OSCILLATOR GAIN and tune the 4 POLE BANDPASS FILTER. Then we align each RF AMPLIFIER for maximum transfer of signal and if too sensitive we back off on the MINIMUM TRIGGERING LEVEL for a net gain of 73dbm. Then we set the SIDE LOBE SUPPRESSION. Next we set the MODE A and MODE C GATES and the FRAMING in the DECODER section so the respective mode A and C ATC interrogations are processed properly. Next we test the ENCODER section by checking all 4096 mode A and 10 mode C pulses as well as the IDENT. This is also where we clean the 4 rotary code selector contacts and the power/mode switch. Next we address the REPLY SECTION by adjusting the PULSE WIDTH of the reply. This signal is handed off to the CAVITY OSCILLATOR where the FREQUENCY and OUTPUT POWER (200 Watts RF nominal) are set using attenuators and a dummy load to keep us safe from the low level microwaves. We always recheck the LOCAL OSCILLATOR and the CAVITY OSCILLATOR after 30 minutes warm-up for drift, as these circuits are temperature sensitive.

TO INCREASE RELIABILITY:
* We inspect and clean all rheostats and code switch wafers. Where necessary we will polish tarnished worn code select contacts.
* Check or repair shielding and grounds near RF circuitry.
* Rattle test. We replace or tighten missing or loose hardware.

All the above is included in the standard $195 alignment/recertification.

WHAT IS NOT INCLUDED IS:
* Troubleshooting and repair of defective circuitry.
* Repair of broken mechanical parts such as faceplates, knobs, wafer boards, etc.
* Bulbs and photcells.

If your transponder does require additional service we will contact you with an estimate. If you choose not to proceed we will bill you the $75 assessment fee.

ONE VITAL NOTE:

We've been repairing transponders for 40 years with up to 3 full time techs and were proud of our 95% success rate. However due to aging components and parts availability we cannot guarantee a successful repair. We no longer strip aging components off old circuit boards due to reliability issues and we WILL NOT authorize a return to service of a questionable transponder. If we cannot properly return your transponder to service it means it is not safe and should be retired anyway.

When you fill out the service request on this site and the info you provide becomes part of our workorder. I read what you wrote. We have 3 FAA certified locations at 2 airports and one at our home. You ship to our 1467 Sanibel Ln, Gulf Breeze Fl 32563. We service transponders 3 days a week.  Most transponders have several alignment points and most often an alignment is all that's needed. If a repair is required we evaluate the symptoms and circuit for troubleshooting options. All repaired units receive an alignment. There are many common faults that are particular to any given model or make. Most are well known by us however there is often something new. Some units are not worth fixing and If so we can advise you of your options.

Open 30 day credit is extended to all customers as long as you sign the form you will attach to your transponder (instructions will follow).

Please follow our shipping advice .  Details regarding our return shipping policy are also found there.

If you would like the FAR 91.413 24 month transponder certification log entry please include your aircraft make and model.

The maximum fee accessed for a non-repairable transponder is $75 + return shipping. If you do not want your transponder returned we will dispose of it and not charge shipping.

  For our repair warranty policy.

Some transponder failures are due to circumstances that are highly unusual and may have originated elsewhere.  Please note our commitment to follow this through to the end even if additional warranty or tech support is required and at no additional expense to you, other than stated above.