M8 owners please read need help

[WVRACER]

I have a M8 and i was wondering if you can change the crystal in the radio module it looks sealed

the airtronics web site said it needs to be retuned if you do this

can anyone please help me out with this those modules are very expensive and if you should have three when you race your talking 150 bucks in 3 modules
thanks for the info in advance

wvracer

[DLF]

I have not yet changed the crystal in mine, but I was under the impression that you could change the crystal. Just pop the cover off. However, again, I haven't done it yet so I would wait for a response from someone who has.

Dana F

[Serius Black]

Yes, the crystals can be changed. You do have to pry that little cover off, just be careful. The glue they used is just strong enough to require a little force be used, but you could also crack the module.
Do any of you guys know why the crystal is "factory sealed", as if they don't want it removed?

[rcaddikt]

Here's the cover too remove. Like Serius Black said, BE CAREFULL in doing so.

[Fafnir]

It is sealed because "technically" it is against the law to change crystals unless you are licensed to do so.

[WVRACER]

what about that whole retune thing thay have in there Q&a section on the web site

and thanks for your replys

[Serius Black]

Originally posted by Fafnir
It is sealed because "technically" it is against the law to change crystals unless you are licensed to do so.

So, the hobby shops are technically breaking the law selling crystals?
I've been in the hobby for over 20 years, and it wasn't until recently that I really thought about this. How did Hitec get FCC approval to build the Spectra module? Or Novak with their new gadget? There must be some huge loophole somewhere.

[Moo-Shoe]

No loophole involved in getting the HiTec or Novak synthsized modules. It's all in the testing and what not. You just have to submit a design to the FCC for approval. They just want to make sure your signal doesn't "leak" over to another band.

And to say it's illegal makes it sound like they can throw you in jail for changing your frequencies. Not really... All the FCC can really do is fine you and/or take away your gear. :)

[DLF]

From the FCC:



§ 95.645 Control accessibility.
(a) No control, switch or other type
of adjustment which, when manipulated,
can result in a violation of the
rules shall be accessible from the
transmitter operating panel or from
exterior of the transmitter enclosure.
(b) An R/C transmitter which incorporates
plug-in frequency determining
modules which are changed by the user
must be type accepted with the modules.
Each module must contain all of
the frequency determining circuitry including
the oscillator. Plug-in crystals
are not considered modules and must
not be accessible to the user.
of the limit specified in § 95.637.

Dana F

[DLF]

Hmmm...the more I read that, I don't think I copied the right part.

Anyway, I downloaded a particular PDF file. Here's the link to several:
http://ftp.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1998/

Dana F

[chizzler]

what the heck are you guys talking about???? you can change the crystals on the m8.......its not sealed because i do it all the time. why would it be illegal, i mean, they sell extra transmitter crystals...:rolleyes: by the way, you dont have to pry that little black thing off!!!!!!!! heres how you are supposed to do it..........

1. unclick the module from remote, be careful when pulling it out, theres 6 metal wires you DONT want to bend on the right side, so pull the module out straight ;)

[chizzler]

heres a pic of the little metal thingies.....

[chizzler]

2. then all you have to do is take your module and unscrew 2 screws, and the crystal is right in the middle. its not brain surgery to take out the crystal, so i didnt take a picture of that. just swap it out, screw it back together, and pop it back in and you should be good to go :D

[WVRACER]

so whats the perpose of the module just to switch between 27 and 75 or is there any other perpose

thanks chizzler

for the step by step
i just don't want to miss up my radio it cost to much to replace

thanks again to everyone

[chizzler]

yes, it designates the band between 27 and 75. i know for sure that if you have any other band for rc or try and change it tthat would be illegal ;)

[chizzler]

oh and be sure to carefully take the crystal out, take your time! :)
i like to try and not touch anything else in the module when doing it to prevent any problems

[Serius Black]

So, why risk damage to delicate components inside the module by taking the entire thing apart, versus removing the little cover and being able to change the crystal within seconds, any time it's required. If you race much, you know that what I'm saying isn't crazy talk. At our track, if someone in your class has the same frequency and out qualifies you, you are required to change your crystal. It's very common for guys to not check the printout before the heats, and end up changing crystals at the last minute.
I would strongly advise you to NOT pull your module case apart. The plastic will eventually strip from constantly running the screws in and out, and you risk damage to other components internally. Besides, pulling the module off of the radio constantly increases the possibility of damaging the pins on the radio that slide in to the module. Do this and you're out a radio for a while.
I have no problem with changing out crystals, I was just curious why Airtronics made it a point to glue the crystal cover on, knowing that just about everyone that owns the M8 would be changing crystals. I think they're just covering their tail in the event the FCC ever decided to come after them.

[Serius Black]

Originally posted by chizzler
heres how you are supposed to do it..........



Uhhh.... No. You're actually the first person I've ever seen do this. It's like breaking in an unlocked door.

[chizzler]

Originally posted by Serius Black


Uhhh.... No. You're actually the first person I've ever seen do this. It's like breaking in an unlocked door.

so youre gonna say they put those little clips on the module for no reason?????????
ok now thats plain stupid, if we werent allowed to change crystals then that thing would be locktight and you wouldnt be able to take it out whatsoever. all you do is press the 2 clips on the module and pull it out, no problem. :)

then, why can we change our AM crystals?
FM is the same thing same channel, all your doing is changing the crystals, so am i being illegal changing my AM crystals too? something to think about it........;)

[Moo-Shoe]

Technically Chizzler, we all are in violation of FCC regulations when we change crystals. The fear from the FCC is when we change crystals without having the radio retuned, we produce sloppy" signals. These signals have the ability to interfere with things other than RC cars. That is the main reason behind the no crystal change policy. Is the FCC driving around from track to track busting people? Of course not! But, if you want to go by the letter of the regs, then changing crystals (FM or AM) is not allowed.

Airtronics put the clips on the module so you can replace the module (with different crystals in it) to change frequencies. Who owns more than one TX module? At $60+ per module, I'd venture to guess that no one in their right minds has more than one.

Why do hobby shops sell replacement crystals? Have you ever broken a crystal? Crystals are not bomb proof. It is possible to ruin a crystal while it is installed. In this case, you buy a replacement crystal. According to the FCC, you can replace the crystal with the same frequency you started with. You are supposed to have the radio retuned even if you use the same frequency.

The funny thing is, if you look at aircraft radios, most of them have tuneable frequencies. The FCC has allocated over 100 frequencies for aircraft use. Who wants to carry around over 100 sets of crystals? Why us surface guys have to suffer with 36 frequencies in the US is beyond me.

[chizzler]

The funny thing is, if you look at aircraft radios, most of them have tuneable frequencies. The FCC has allocated over 100 frequencies for aircraft use. Who wants to carry around over 100 sets of crystals? Why us surface guys have to suffer with 36 frequencies in the US is beyond me.

you are totally right MOO, ive read into that about the airplanes, i mean seriously, how many rc airplain people do you see around you? :D
i know around me ive never seen any flown except those by my lhs, and i know people that have them, but obviously i live in the city, so its kinda hard to fly them ;)
doesnt the government issue these to the fcc, like rcs get so and so and airplanes get ALL this?
thats really odd, because if they are anti-changing crystals they would notice that usually you have 10-20 car a race at time, which is alot of crystals....and usually you need a channel or 2 separation to be safe enough to keep from glitches, and 36 channels by far is not enough to keep a bunch of rc guys from getting disgruntled in a race :)

[rcaddikt]

I honestly don't know why anyone would remove the whole module instead of just removing the little cover and pulling the crystal out. IMO the cover was put there for that reason. If Airtronics wanted us to take out the module, unscrew/take apart the module to get to the crystal, then why did they put that convenient little cover/opening there?:rolleyes:

There's no way I'd go through all that just to change the crystal.

:)

[WVRACER]

so what your saying here is that it is ok to do so. thanks everyone for your responses i feel better
yea black my track is the same way but the two other guys that have m8's do have 4 modules each but i don't think i need to worry about that now thanks all i never thought a simple little question would spread into a big debate on the process of the crystal change but it has been interesting learning from you guys

thanks

wvracer

[Serius Black]

Originally posted by chizzler


so youre gonna say they put those little clips on the module for no reason?????????
ok now thats plain stupid,

You didn't read my entire post. I'm just wondering why you choose to unscrew the module case to change the crystals, when you can just pop off the little metal cover and have quick access all the time. It doesn't make sense.
And, as Moo-Shoo stated, the module is removable so you can change the module, not so you can pull the module out to tear it apart. It's actually pretty smart on the radio manufacturers part: If the FCC decided to crack down on us surface r/c guys, we'd end up HAVING to buy new modules to change frequencies. Airtronics would be in the clear because they've got that nifty little seal GLUED over the crystal.

[JitsuGuy]

Okay, so I had to change a crystal in my radio, and a crystal in my Rx. Anyway.... Do you all re-glue that lame cap back on the back of the module or just throw it in your tool box? Dude, after just pulling it off once, I don't trust it'll stay on there by itself w/out regluing it... So, did you all put yours back on?

Thanks,
Jits

[rcaddikt]

I just put mine back on, without re-glueing and it has stayed on there. BTW, I also have an Airtronics CX2P, which has the same basic set-up as the M8, module wise. And I've changed the crystals in it the same way as described above, for 3 yars now. I've never had any problems and the cover has stayed on just fine.

[nomead]

I unscrewed the module as described above, and then just popped the little bubble cover off. Didn't crack the module case and I can change crystals. One thing that always bothered me, look at all types of transmitters and you will see that RC is the ONLY one that is frequency locked to one channel. Ever use a CB/HAM that has only one channel? I wish Airtronics would make a spectra module or something. At $25 a set of FM xtals, the cost of the module and rx (Novak XXtra) would pay itself over for most of the racers out there.

[Moo-Shoe]

Rumor has it that Airtronics is working on a synthesized module for their surface products. Unfortunately, it's not that easy to get something like that through FCC approval.

[Usagi]

Yes what are you guys talking about? changing them is allowed..... oh..........