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AM Radio Problems!

E

e owner

Newbie
Joined
Jan 17, 2011
Messages
15
Location
Everett area
DO NOT REPLY WITH "Buy a 2.4Ghz radio system"!!!​

This is a thread for fixing or improving AM or FM radios!​

So here's the deal
I've had AM radios for years and never really had many problems/twitches. My rustler e-revo emaxx etc NEVER had twitches unless I rubbed the antenna on some metal or something stupid. Although this radio in my crawler is angry. 5 ft and it gets the jitters, 6 more inches and it jumps around uncontrollably.

I've tried everything i could think of, different crystals, longer antenna, batteries, different antenna positions, checked all the solder joints in the TX and RX. I'm stumped. Any advice?
 
e owner said:
DO NOT REPLY WITH "Buy a 2.4Ghz radio system"!!!​

This is a thread for fixing or improving AM or FM radios!​

So here's the deal
I've had AM radios for years and never really had many problems/twitches. My rustler e-revo emaxx etc NEVER had twitches unless I rubbed the antenna on some metal or something stupid. Although this radio in my crawler is angry. 5 ft and it gets the jitters, 6 more inches and it jumps around uncontrollably.

I've tried everything i could think of, different crystals, longer antenna, batteries, different antenna positions, checked all the solder joints in the TX and RX. I'm stumped. Any advice?
Click to expand...

That sounds exactly like what happened to me when I had my rtc radio. After switching everything out it turned out to be a broken receiver but not anything to with the antenna.
 
Hmm, I suppose it could be a faulty receiver. It certainly hasn't had an easy life.

Just a FYI it is a traxxas micro RX paired to a TQ3. I'll have to try a different RX.

You're a funny guy :)
 
My guess is that electrical arcing coming from the motor is causing the glitching.

Do you capacitors installed on the motor?

Assuming your not using a brand new motor, you should also cut the motor comm brushes and replace the brushes.

Finally, try running the Rx from a separate battery pack (vs using your ESC's BEC).

Narly1
 
Narly1 said:
My guess is that electrical arcing coming from the motor is causing the glitching.

Do you capacitors installed on the motor?

Assuming your not using a brand new motor, you should also cut the motor comm brushes and replace the brushes.

Finally, try running the Rx from a separate battery pack (vs using your ESC's BEC).

Narly1
Click to expand...
+1 (although I don't know about the seperate battery pack).

The older AM/FM radios were VERY sensitive to antenna length & quality. They were also horrible on picking up electrical noise.
-Caps on the motor are a MUST DO!
-Doing a freshening on the motor may help (do you see arcing off the comm when the motor is running?)
-Try to keep the antenna away from the ESC as well as motor wires.

Swapping in a different RX would be good to try.

Is this a recent event, or has this always been an issue with this rig? If recent, what is different?
 
Sounds like the samething I am going tru. And with a traxxas TQ radio. And I tryed a few things. But I just gave up and ordered a cheapo 2.4 radio from hobbyking for $27 shipped. Will be here next week. Good luck!!!!
 
Charlie-III said:
Ummm....he stated he tried different crystals....
Click to expand...

I know he did. I used to see people come in the LHS I worked at with crystal issues and they were trying crystals that had been floating around in their tool boxes. That's why I said "new" crystals. They are just really thin, small slivers of quartz so they damage really easy.
 
Narly1 said:
Sorry, I meant temporarily try a separate battery pack. Isolating the receiver from the ESC's BEC circuit just eliminates another noise path from the list of things to check.

Narly1
Click to expand...
OK, I will accept this as a valid answer...."some" consider this a permanent fix which I DON'T agree with."thumbsup""thumbsup"
 
killswitch said:
I know he did. I used to see people come in the LHS I worked at with crystal issues and they were trying crystals that had been floating around in their tool boxes. That's why I said "new" crystals. They are just really thin, small slivers of quartz so they damage really easy.
Click to expand...
While I won't disagree.....I will say the chances of multiple crystals failing at the same time are unlikely. I'm a field service guy/ex-facilities guy....I run the percentages which yields that "while possible" is "unlikely".

We will have to wait and see what the OP has to say.:roll:8)"thumbsup"
 
Woah! Lots of replies, good to see! :)

I have 1 cap on the motor (PO never installed the other 2?) almost brand new motor zero arcing.

It has always been a problem with this rig. Although it has recently gotten worse when I rebuilt the whole truck. I must be due to the close placement to the esc.

I'm going to due a bit of troubleshooting with a known good system tonight and get back to you guys. This receiver used to be in my brothers merv. He changed from a glitch that sent $500 straight toward a rolling tire. So I could be dealing with a lemon. If all else fails I'll just "share" ;) the 2.4 radio in another car..

Thank you for all of the suggestions! None will be overlooked.
 
Because I can, that's about it.

I couldn't agree more. I was simply trying to fix this system while helping others who may have radio problems.
 
Not many running crystals anymore, especially in crawlers.
People are amazed when I go carpet racing with my early 80's (?) Magnum Jr's.:roll::lmao::lmao:
I bought the 3PM-x so I can ditch multiple radios, save model memories (instead of tweaking things when I change vehicles), not deal with frequency conflicts (although not much anymore, most are running 2.4ghz), etc.

I happen to really like Futaba, so that is why I went 3PM-x.

Good luck on your troubleshooting, hopefully it's not a bad RX.

(PS, my 1st Futaba was the beige box with the trigger off the back, I still have 2 of those!:shock::lmao::lmao:)
 
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