futaba recievers still overheating!

[dave g]

well bruce had the old overheating problem again in the final on sunday with the futaba 3vc hss.. receiver thermalled in the final causing total radio loss until it cooled down.

i seem to recal someone saying that putting it in french mode keeps it cooler as it uses less channels or less scanning,cant find any solid evidence of this but the usa guys are getting no joy from futaba with the same thermal issues.

any one know?

[DCM]

Dave, this is a long shot, but is it possible to bypass the +ve side of the servo's by hard wiring them to the receiver +ve, leaving the servo's -ve and signal wire in the plug, so the power going to the servo's isn't passing through the receiver?

[dave g]

i think we tried that last time when he was running the 1/5th scales and still did it..

its the fasst system that hes using,just thermals as soon as it gets warm.

[DCM]

thats crap then, no real work round unless you slow the system down, but the whole idea of running FASST, is response times.

[dave g]

yep,first warm day of the years racing and it thermals in the final..bang on cue same as last year.

looks like its going to have to have a spekky module fitted to it then if this french mode dont work.

[Northy]

The power just comes into the board and out again on a big thick PCB track anyway, so should cause any heat issues :(

G

[dave g]

from what i can gather its the 2.4 chip in the receiver that gets heat soaked then it shuts down..then comes back on when cooler.

[Northy]

Holes in the case? Bond a lil heatsink onto it? A fan? :confused:

G

[dave g]

its smd stuff graham,the case of the receiver is 60c when it thermals so lord knows what the board is at.

tried a fan before didnt work :(

[simoncrabb]

I've never heard of that happening before.

I had one of those receivers fail totally, but not overheat.

What sort of car is it in, why is it getting too hot?

[dave g]

2 high power servos and its in and enclosed receiver box which wont help but no choice..its only the futaba's that do it..remember loads of them doing it last year and the year before at slough.

[Northy]

its smd stuff graham,the case of the receiver is 60c when it thermals so lord knows what the board is at.

tried a fan before didnt work :(

SMD stuff can still be cooled :confused:

[dave g]

sorry thought you meant put heatsink on smd..but we tried allsorts before..even on the 5th scale out of the radio box and still did it.

just wondering if anyone had heard of a fix or solution for it

[Northy]

if it's an smd ic it can still have an heatsink bonded into it.... if there's room.

G

[Chris Doughty]

have an RX box lid with holes in it that you run in the dry?

I remember seeing Savoya's car with a million holes in his RX box.

if you just do the lid you can switch it out if the weather gets wet

[dave g]

still does it chris..we had it mounted on the outside of the box on the 5th scale and did it.

i had heard that there were 2 different circuit board colours,one overheated the other didnt but futaba just deny anything.

btw this is with 2 different receivers of the same model number...tried another tx and module also.

fit a spektrum module or the 40mhz module and it doesnt happen

[bodgit]

Found this on another forum it might help
The suggestion by Futaba to stand the rx on its side has the effect of almost doubling the surface area for convective heat dissipation. So any rx generated heat can get away quickly rather than add to any other heat being absorbed.
The components that are getting over heated are (I am told) on the underside of the rx so this also gives a better route for the heat to escape rather than having to migrate up through the upper PCB and out through the top.


Read more: http://www.rcuniverse.com/forum/m_7807297/mpage_5/key_/tm.htm#ixzz0leacHEeh (http://www.rcuniverse.com/forum/m_7807297/mpage_5/key_/tm.htm#ixzz0leacHEeh)

[simoncrabb]

I guess you gotta get some serious cooling to it, maybe out of it's case, on it's side, heatsinked, with a fan, and a million holes in the radio box!

Add some belts and braces too...

:confused:

[super__dan]

Dave there are two receivers you can use with the Futaba, the top one comes with it and has 2 aerials (1 is internal) and then there is a lower spec 2.4ghz one, not sure it's high responce, which sounds like what you want???

EDIT, I think I'm talking rubbish here now I've looked as the 603GF says is not compatible with FAAST

[dave g]

not sure what hes going to do,if it were me i would have the spekky module in it and not risk it,didnt know there were a couple of different futaba receivers

[super__dan]

Dave, see edit, I'm no longer sure I'm right :(

[col300]

Dave there are two receivers you can use with the Futaba, the top one comes with it and has 2 aerials (1 is internal) and then there is a lower spec 2.4ghz one, not sure it's high responce, which sounds like what you want???

EDIT, I think I'm talking rubbish here now I've looked as the 603GF says is not compatible with FAAST

Think you are right Dan, the receivers are R603FF and R603FS though.

[ianjoyner]

I've run both the R603FF and R603FS, the FS is the one with two aerials, I couldn't tell the difference between them in range or resposne.

My understanding of the over heating issue is that it is a component tolerance, rather than an intentional thermal cut off. So basically they stop working, the actual temp varied quite a bit between receivers. I believe Futaba started testing them and basically not selling the ones with a low tolerance. A gold spot on the receiver should indicate that it is a more recent receiver and should be okay, even some with out gold spots should be okay. I don't believe the problem has ever been due to heat actually generated by the receiver. I think the heat can only come from either something hot near by, or the high power servos pulling current through the connectors and PCB. The receiver shouldn't be getting to 60C, I run them on electric cars and I've never noticed them above ambient. If your box isn't touching anything hot I would make sure you've tried bypassing the receiver with the red lead, not even connecting the servo red lead to the receiver.

Most of my understanding has come from talking to Ripmax the UK distributor, give them a call, they may be able to help, especially if you have one of the older un-tested receivers.

http://www.ripmax.com/rm_contact.asp

[dave g]

as you say,you run electric and only 1 servo,we use 2 under high load,the big plane lads are the same so i think thats why electric lads dont see this problem,and it only happens after around 15-20 mins which is in a final.

if you saw the amount of 8th cars that had runaways over the last 2 years or thermal shutdowns on the futaba receivers on hot days you wouldnt believe it.

all suggestions been tried im afraid,the usa forums are full of the problems..and no positive fixes since futaba wont acknowledge a problem.

thanks anyways.

[steelie600]

There is a fix, GET A SPEKTRUM!!! not once have i had a thermal shutdown and ive been using the same rx for 18 months and in exactly the same cars as those that have been shutting down with the futaba's.

Same with the KO system getting intereference due to overheating, the spekky just doesnt get it. Its the DSM system you want not the DSM2 as that is also fraught with issues but the original DSM as found in the DX3s, DX3.0, DX2.0 is so reliable its untrue

[dave g]

yes thats the only other step which is what will be happening i think if this french mode dont work.

[ianjoyner]

If the servos bypass the receiver I don't see why it matters how many servos you have? Both the red and black wires would have to avoid the receiver.

[dave g]

well ran it today at deerdale solid for 40 mins in french mode, receiver was barely warm so hopefully this may cure it.. whether it changes when there are other 2.4 systems running i dont know but certainly worked fine today :)

[rcdunk]

have had this problem at the last 3 rallycross nationals
the car runs fine all day through quali not a problem in any shape or form
first final 10 mins not a problem bump up 5 to 7 mins into second final car just shuts down dead nothing happening

any updates on solutions ? judt dont want it happening again starting to piss me off a bit lol contemplateing going back to 40 meg

going specktrum not really an option spent enough getting 2.4 ghz futaba as friends had had problems with their early stuff

[dave g]

nope
bruces started doing it again so he got a sanwa exzes plus like mine,no problems now :)

sorry cant be anymore help but futaba wont acknowledge theres a problem so therefore no fix im afraid.

you could try the french mode which i think is on the module in the tx and mount the receiver on its side so air can flow around the bottom of the receiver as thats where the 2.4 chip is located and where it thermals.

[rcdunk]

so phone call to ripmax is not worth the bother then lol cannot afford to go changing handsets etc look's like its back to 40 meg then

had a think about it and its only done it this year since changed car gone from losi (mounted at front) to rc8b (mounted at the back) wondering if the closeness to the engine is causing it to thermal out

[stox217]

Try taking it of high response and see what that does?

[dave g]

its the 2.4 chip that overheats.

the futaba is constantly scanning and channel hopping,it does this hundreds of times a second if i recall

in french mode there are less channels so it doesnt scan as much or the scan is slower,so less overheating,but it still does it.

i dont think there is a workaround but keep looking you never know..

[rcdunk]

its not a high response one anyway

will keep looking and see what I can find if not back to 40 meg me thinks lol still got friends running 40 meg they have not had to change x tal's all year seams no point using 2.4ghz if you dont have to keep changing lol