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Failsafe failing?

Old 05-21-2006, 01:31 PM
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kengentry5000
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Default Failsafe failing?

I have the stock Duratrax failsafe module on my Firehammer. It has always done the job well. I also use the stock Futaba Magnum Jr FM radio. The range I have gotten in the past on the radio has been great. I don't think I have ever driven the car out of range.

Now I have an odd problem. I drive about 120 feet away and my throttle drops off. I am pretty sure the failsafe is kicking in. My steering works fine while my car just sits there.

I recharged the RX battery and put new batteries in my transmitter - no change. I had purchased this same Futaba radio set for my 1:10 scale electric so I swapped the receiver modules between the two cars but reused the channel 62 crystal -no change. I swapped crystals in my transmitters to try the other transmitter - no change. The only thing I haven't tried is running the Hammer on the other crystal (channel 63) because if the steering is working how could the receiver crystal cause the failsafe to kick in falsely?

Anyone here ever have a 'soft failure' like this in a failsafe. Mine works correctly when I test it (before every run) and the throttle servo works fine in less than 120 feet. When the car gets just beyond that range and stops I can walk 5 feet toward the car and the throttle servo works again.

Luckily I have not had any runaway problems with this failsafe yet.

Any troubleshooting ideas? A new failsafe is not that expensive but if it's not the failsafe crapping out then I'm buying something I don't need.

BTW - I am running a Futaba S3302 steering servo and a Hitec 645 analog throttle servo.

Thanks for any other ideas to check,
Ken
Old 05-21-2006, 02:43 PM
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tizdaz
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Default RE: Failsafe failing?

dont sound like a prob with your faile safe m8y (infact id say ya fail safe is doing the job 100%) sounds more like a prob with your reciever which is why your fails safe kicks in because your reciever loses signal form your transmitter, check your antenna cable is ok (might be split somewhere) & still well connected to the reciever..it may have come loose etc.

Old 05-21-2006, 03:19 PM
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kengentry5000
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Default RE: Failsafe failing?

I replaced the antenna wire on my original receiver. I had an electronics tech in our company hardware lab solder it for me to get it right even. It didn't help. That's why I swapped in another receiver. The second receiver didn't help either.
Old 05-21-2006, 03:27 PM
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bigger the better
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Default RE: Failsafe failing?

I just had that problem Friday and I am thinking it ended up being my servo because it finally just stopped working all together. I changed over to a new servo and all worked till today when my new one went haywire too but, this one just came back from having problems before.[:@]

Have you tried putting it against something unmovable, removing the failsafe and trying the same distance without the failsafe?
Old 05-21-2006, 04:42 PM
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J_D
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Default RE: Failsafe failing?

i think its the failsafe because obviously u havent lost contact with ur reciver since u can still move the wheels....
Old 05-22-2006, 12:23 PM
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kengentry5000
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Default RE: Failsafe failing?

That is what I was thinking too. One other change I made a while back was to put a M6 wheel nut on the flange on top of the radio box to keep the antenna tube from slipping out. I am going to remove this to see if there is any odd RF interference or attenuation problem having a circular chuck of metal around the antenna wire.

Probably not the problem but it's a quick test before going off to buy a failsafe.

Ken
Old 05-28-2006, 06:51 PM
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kengentry5000
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Default RE: Failsafe failing?

Update

I put a fresh charge on my NiMH 3300 receiver pack just in case that was the issue. Problem still there.

Last time I fiddled with this when the car started misbehaving (100 feet away) I put my transmitter down and walked over to the car to see what the failsafe and servos were doing. The servos were twitching like crazy - steering and throttle/brake. It would twitch for a while and then settle down and then start twitching again.

The failsafe has green and red LEDs. They have a specific flash pattern for battery or RF failure. The LEDs were both OFF. That would seem to me a power glitch of some kind. I disconnected the failsafe (and throttle/brake servo) and the steering servo still twitched back and forth.

Two questions come to mind:
- Could the spark plug or ignition module causing glitching like this? This is a very repeatable problem.
- My steering servo connector broke in half. I pushed the metal pins back into the broken portion and the connection seems solid. Could that break be causing some problem?
Old 05-28-2006, 07:05 PM
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Default RE: Failsafe failing?

hi ken. the problem is the failsafe itself. i bought mine from king rc it done the same thing on the third tank of gas. all batts fully charged. firehammer gets 100 feet from me and it stops on a dime. then you start walking to it and about 10 feet away it takes off again. make sure your batts are fully charged and u have a full tank of fuel then take the failsafe off the firehammer i bet it runs the whole time without stopping. drive it without the cover on it and let it screw up sit the remote down and walk over to it u will notice that the red light is on on the failsafe. hope this info helps u.
Old 06-10-2006, 02:06 AM
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Default RE: Failsafe failing?

Do diffirent Failsafe's have diffirent ranges? I have this cheap one[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHLV3&P=ML]Dura Trax[/link] I am thinking about replacing it with thia one [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHUH6&P=ML]Venom[/link] Or this one [link=http://www.emsjomar.com/SearchResult.aspx?KeyWords=Failsafe]Jomar[/link] I have the same Problem like yall distance! On my FG 1/6 scale Bigfoot Monster Truck Here->[link=http://www.largescalerc.com/FGMonsterTruck.html]My Bigfoot[/link]
Old 06-27-2006, 04:11 AM
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Default RE: Failsafe failing?

Hi all, Well I had the same problems yall are having, the 120 foot range. I took out the DuraTrax[sm=bananahead.gif] & installed a new Venom-->[link]http://www.venom-racing.com/products/electronics/vfs/index.htm[/link] & did what it said to do here-->[link]http://www.venom-racing.com/instructions/vfs.htm[/link]. & now the range is as far as I can see it!, if not farther[sm=sunsmiley.gif]. So it was the failsafe & not the reciver[sm=spinnyeyes.gif]. I guess you get what you pay for!
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Old 06-27-2006, 09:05 AM
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Default RE: Failsafe failing?

im of the opinion when it comes to electronics and such ie radio gear/ stereo equipment musical equipment RC gear, theres only one statement i can think of that rings true.
Buy Once Cry Once...... i have heard of the Duratrax failsafes having issues on nitros too.. the ingnition CAN cause some issues. i just got the baja a few weeks back, as did my neighbor. mine was glitchy and generally a pain. neighbors is working fine so far. i put in my JR XS3 Pro Tx with a JR RS310 micro Rx. the glitching was mostly releived but still there kicking in the failsafe. the Stock set up is FM, 27Mhz. the Jr is FM Synth in 75Mhz. for me BOTH had issues on the Baja, but on my CT5 onroad the JR works flawlessly. so i bought a Spektrum last week and its not even so much as sneezed with glitching or other issues.

i would say replace the failsafe, its only a 20.00 item. if thats not the problem, its the least amount of money spent for nothing and its always good to have a spare failsafe around. unlike buying a new radio and afterwards finding the 20.00 failsafe was the culprit. for me it has something to do with the ignition causeing interferance, but no idea why my neighbors is fine. unless i got one of the first runs and his came off the line weeks later with some improvments.
Timmahh
Old 06-27-2006, 09:36 AM
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Default RE: Failsafe failing?

Same thing was happening to me and it turned out to be the fail safe. It seemed to have failed due to the large current draw from the large scale servos. It basicly just slowly cooked itself to death. I have gone through a Venom and a Dynamite and now I'm trying a XTM. I should mention that I'm running 3 805's, 2 for steering and 1 for front/back brakes.
For 20$ just buy a new one and see if it works, you can always return it.
Old 06-27-2006, 09:42 AM
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Default RE: Failsafe failing?

I have a few items to mention in my quest to fix this problem:

- Removed failsafe completely - problem still there
- Unplugged throttle servo when out of range - steering servo still twitching
- Receiver has better range (problem did not show up at least at further range) with my 1:10 scale electric truck
- Posted to the Futaba Support forum here on RCU - They said there have been Firehammer-specific radio range problems with receiver battery packs not charged enough (or wearing out a cell) causing the receiver to act weird. They recommended trying a new receiver battery. I bought a new 3000 mAh NiMH pack and charged it this morning. I will be able to test it in the next day or two if the rain backs off! [:@]

I charged my old pack and then put it on my home-made discharger (automotive tail light bulbs). I then measured the voltage while under this load. The voltage was around 4 volts. I have not tried this test on a good pack so I don't have a good value to compare to. The fixture has 8 bulbs (originally for my 7.2v electric truck packs) so the current drain is much higher than the Firehammer electronics.

I will post back when I have some results.

Ken

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