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Hitec WARNING – 2.4GHz AFHSS System locks out when used with an optical kill switch.

Source: Hitec Service Bulletins

2.4GHz System Warning

May 31st, 2011
WARNING – 2.4GHz AFHSS System locks out when used with an optical kill switch.

Hitec USA’s service department has received reports that some users of our 2.4GHz AFHSS System have experienced system lockouts that have resulted in the loss of control of their aircraft. While there are several factors that can contribute to this, including poor power distribution or improper equipment installation, the increased volume of these reports has prompted an investigation in order to determine the cause. Our preliminary observations have suggested that the use of Optical Kill devices in conjunction with ignition engines is somehow causing our system to fail.

In light of this discovery it is suggested that users of our 2.4GHz AFHSS system discontinue the use of Optical Kill switches until a determination into the cause of these failures is made and a solution is found. We sincerely apologize for this situation and to anyone that has been affected by this issue.

HS-20110524 HS-7940/7945/7950TH Glitching
In some cases, when using the 7940/45/50’s in applications that require a very long extension, they may randomly jump (glitch) when powered by 2S LiPo/Li-Ion batteries. Although this may occur with many systems, it is most commonly found when using JR/Spektrum type RX’s, especially the Power Safe versions. We have discovered that due to the resistance in long extension wires, the signal voltage drops, thus causing the issue. We recommend that only high-quality, twisted, 22-guage, high strand count, gold connector extensions be used. In the event that this does not resolve the problem, there are a few options. The use of a signal line booster like that made by Spektrum, and soon to be available by Hitec, resolves the issue in almost all cases. Another option is to solder a .22 tantalum capacitor between +/- on the extension. These solutions are typically only needed when using Li-Po/Li-Ion batteries to lower the voltage below 7 volts and is not needed when using 5-cell NiCd/NiMH or LiFe batteries.

We are aware that these are high voltage servos designed to operate at the maximum voltage allowed for maximum performance. However, to accommodate some radio systems, steps may be required to assure the above issue will not occur. Hitec apologizes for any inconvenience this may cause and is working on a series of new Ultra Heavy Duty extensions (with and without boosters) that will resolve this issue.

HS-20100520 HS-79XX Series Servo – Minimal Load Jitter
Applies to HS-7965/7985/7955/7954/7940/7950 servos
Customers have noticed that these high resolution servos have a tendency to jitter when using 7.4 volt power packs and a minimal load is applied. This is due to the high resolution circuit adjusting for slight position variances in the gear teeth. This usually only occurs with minimal loads, for example, when the plane is on the ground in a static position. Once airborne the servo experiences flying loads and the issue resolves itself and should not impact on the flying experience.

TX-20100520 Aurora 9 Transmitter – Using EPA and D/R Functions Create Dead Zone in Stick Travel
We have confirmed customer reports of a software bug involving the End Point Adjustment and Dual Rate functions. When both functions are at their highest settings, there is a significant dead zone at the stick endpoints. Until this issue is resolved in a future software update, it is advisable for customers to keep either the D/R or EPA setting at 125% or less and the other at 120% or less.
RX-20100520 – Optima Receiver Antenna Breaking – Applies to Early Production (before February 2010) Optima 6, 7 and 9 Channel Receivers
It has come to our attention that some customers are breaking the “wisker” off of the BODA antenna used on the Optima series receivers. If this happen the results will be a decrease of operable range. Hitec has taken steps to resolve this issue in future productions by utilizing a plastic bushing. For existing receivers without this bushing, it is recommended that customers apply a small amount of flexible adhesive such as Shoe Goo around the upper tip of the BODA and the antenna wisker.