Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Nov 17, 2009, 10:58 AM
Registered User
Joined Nov 2009
1 Posts
Help!
Assan 2.4 Ghz module in a Hitec Prism

I've just installed a new Assan 2.4 Ghz module in my Hitec Prism 7. It works well, apart from the following irritating fault, and I'd like to know if anyone else has encountered this problem.
When setting servo reverse it appears to accept the instruction, but on switching the Tx off and then on again, it reverts to the original setting. On the other hand, if I take the module out and set up servo reverse again, it remembers the setting, even once the module is reinstalled.
Is this just a peculiarity of the Hitec/Assan combination, or is there a fault in my transmitter?
Brian Ward is offline Find More Posts by Brian Ward
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 17, 2009, 01:26 PM
Registered User
earlwb's Avatar
USA, TX, Grapevine
Joined Dec 2008
12,428 Posts
Sounds like the TX not the RF module. The TX RF module only deals with converting the PPM signals to RF to be transmitted over the air to the RX and its servos. There should be a option to save your settings somehow, when you make a setting change such as reversing servos.
usually the setting is changed when you press the correct button on exiting a menu selection. But you could exit without changing the setting too.
earlwb is offline Find More Posts by earlwb
RCG Plus Member
Latest blog entry: My Low Wing plane
Reply With Quote
Old Nov 17, 2009, 06:48 PM
Registered User
Joined Aug 2002
5,808 Posts
Quote:
Originally Posted by Brian Ward View Post
I've just installed a new Assan 2.4 Ghz module in my Hitec Prism 7. It works well, apart from the following irritating fault, and I'd like to know if anyone else has encountered this problem.
When setting servo reverse it appears to accept the instruction, but on switching the Tx off and then on again, it reverts to the original setting. On the other hand, if I take the module out and set up servo reverse again, it remembers the setting, even once the module is reinstalled.
Is this just a peculiarity of the Hitec/Assan combination, or is there a fault in my transmitter?
Regularly reported problem with the Assan 2.4GHz after market module not just with the Prism but also other TX with flash card type memory, refer just one HK thread:
Assan module problems with Eclipse & Futaba TX, problem is with the decoupling capacitors of the module which spike power to the electronics of the radio when you switch it off and prevents memory being saved. Until Assan fix their module to be fully compatible with all TX, the quoted temporary "fix" (within TX power system) voids TX warranty and most likely against FCC regulations in USA.

Suggest Spectra 2.4/Optima 7 Combo, which includes telemetry functions, for converting Eclipse, Optic 6 & Prism TX to 2.4Ghz (also suitable for Futaba and other TX with same module types) is best option.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links
A.T. is offline Find More Posts by A.T.
Last edited by A.T.; Nov 18, 2009 at 02:13 AM.
Reply With Quote
Old Nov 21, 2009, 02:45 PM
Jim
WildeOne's Avatar
Ocean Pines, MD, USA
Joined Sep 2004
52 Posts
There are posts in the very long ASSAN thread that suggest the problem (it was id'd as "loss of trim memory" on power down of TX, but could well affect other settings as well using memory. The fix involves adding a diode (1n4001) will do fine to the +vcc line to the RF module. Looking at the TX back, it's the second long pin from the right in the module cavity. You will need to open the TX and find the correct lead, cut it, slip some heatshink over, then solder the diode with the polarity band toward the exterior. Shrink the tubig ... done. Then just close it up. This deal affects the Eclipse 7, maybe the Optic 6 and at least one Futaba TX.

This is apparently caused by a capacitor in the ASSAN RF module, which allows a voltage spike to feedback into the TX memory area on power down of the TX. Not really an ASSAN problem, but an integration issue, which ASSAN and Hitec will likely both ignore. In any case the fix is simple and cheap. (1n4001 diodes are ~ $0 .03 in qty of 100.)

Pictures:
http://www.rcgroups.com/forums/showt...assan&page=291

Also, see page 292/post 4369.

There were a number of other posts describing the issue, but I could not locate them quickly, so just gave the fix info.

Good luck.

Jim
WildeOne is offline Find More Posts by WildeOne
Last edited by WildeOne; Nov 21, 2009 at 03:37 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Corona 2.4 GHZ transmitter module and receiver rbrown3rd Aircraft - General - Radio Equipment (FS/W) 12 Oct 21, 2010 11:45 AM
Wanted Wanted x8 Assan 2.4 module norstaroption Aircraft - General - Radio Equipment (FS/W) 0 Oct 24, 2009 07:50 PM
Discussion JR XP8103 and Assan 2.4 Module norstaroption Radios 3 Oct 24, 2009 07:13 PM
Sold Assan 2.4 ghz JR module, 6ch Rx mj147 Aircraft - General - Radio Equipment (FS/W) 7 Sep 19, 2008 09:34 PM
For Sale JR 9303 Spektrum 2.4 ghz module, 72mhz synthesized module, Xtremelink 2.4 ghz module twohsieh Aircraft - General - Radio Equipment (FS/W) 8 Aug 31, 2008 11:51 PM