Topic: So you've planted it.

 How much trust do you have in your set up once you've done a soil hardness test ? Had the odd sudden arrival, more than once, post mortems revealed all systems working fine. Repaired and flown till complete loss of signal, mega splat ! Still all systems are working fine, hmm. Stripped the outer from  the AR6100e, then with 4 servos, ESC and whizzy bit at the front all humming away merrily, firm grip on the R/X plug block and the lightest touch on the pc board and instant loss of bind. R/X in the bin.So how far do you go to check for serviceability ? 

now crystals are gone people seem much happier to put crashed gear straight back in. dunno why.
any seriously crashed gear gets tested in a hack

That sounds irresponsible. If not you, others could be hurt by using "seriously crashed gear" (your words) in any model, hack or otherwise without first having it returned to the agent for testing and analysis.

did that after my very first crash, was charged 69 quid to fix a 8ch DC futaba rx
guess what, never did it again.

since then i've only ever had to bin a couple of rx's, a few crystals and relegated some to epp gliders where they do just fine.

never had a problem with a rx i've seen fit to return to service

Tell you what. Since we both know its bad practice to fly on potentially damaged radio gear without first having it checked over by an approved agent. Why don't you delete your posts relating to this effect and I'll do the same with mine. This way new comers who don't know or are uncertain of what should be done after a serious crash wont be misguided into thinking its ok to test it in an old model?

If this relates at all...............and yes they are not "up there" to fall, but ..................

Every week I service and race ( well my club's school kids do) 20 plus EP cars. Been doing this since 2006.

These take one heck of a pasting with regard crashes.

I initially only used "quality" make Rx's, servos, etc

Had a few 27MHz and 40 MHz Rx's fail (as distinct from Crystal failures), but so far not one 2.4 GHz Rx has failed, despite weaker casings and buying "budget" gear.

Not one Rx of any type has so far failed while in normal operation after a crash, they either fail IN the crash, during my testing, or they work.

My none too confidence inspiring experience of "agent check/repair" suggests most people are capable of doing a better job using common sense as long as they do not put others at risk till reasonably sure.   

PS..........Did Cactus say he'd test the crashed Rx in a hack around people?

Ok my 2p, I had a argument with a tree at Weston Park, and the model was badley damaged, gear all checked out fine (Spektrum), but as I want to be 100% sure I shipped it back to Horizon, back in two days fully tested and fault free, no charge. 

I would have paid for this check just for peace of mind but getting it free is even better, Nice one Horizon.

I always get my gear checked out after a serious landing 

Steve

I never re-use seriously crashed RX's apart from on the bench or maybe a small foamy if the RX is suitable. This has been habbit from my old 35mhz days that continues to 2.4 although I have yet to badly crash a 2.4 model (touches lots of wood)

Servos are different. Lower power ones end up on throttles, flaps and less important surfaces. High torque expensive ones get put into smaller models one at a time usually on rudders so if they did fail it shouldn't cause a crash 

I throw all crashed rx's in the bin unless they are small ones then they "may" end up in a shockie if the crash wasnt too bad, but anything that writes off an airframe, I bin, personal choice but thats the way I do it 

if i was to replace a rx every time i decked my epp jart or wild thing i would have to take 5-6 rxs with me to the slope ok they are better protected inside the epp model
Ron

if i was to replace a rx every time i decked my epp jart or wild thing i would have to take 5-6 rxs with me to the slope ok they are better protected inside the epp model
Ron

I think foamies are somewhat different in the first place and rarely write an airframe off. If one of my 50cc'ers goes in, I would not dream of using the RX again, its just not worth it to lose another model, let alone the safety aspect. 

evan being an epp i think 50mph plus into the deck would be a bin bag for most models
Ron

Any body care to work out the g forces acting on a rx in a 100 mph dive into the ground?

2.4GHz  (and 35MHz synthesized) receivers do still have crystals - just not replaceable ones, and not really of the same type as back in the day.

These crystals are still vulnerable to impact. Most the other electronics in a modern receiver is pretty tough though, not withstanding actual physical breakage of wires, copper tracks, pcb itself etc.

Looks like I am a lucky one as my foamies only ever go into the ground at 20mph max  Unless of course its an RX fault, and then it goes in the bin anyway 

this thread was brought up not so long ago  being your average flier would range check the rx in a model with  engine running or use it in a foamy
once you start to get into expensive models you renew it some again check them out then fit them to smaller models others bin them right or wrong 
the only rx i have had fail in a long time has been a new one on its first flight
if i was to deck my 26cc extra hard (bin bag) i would not trust it to go into another same size model if it still checked out it will go into an epp model
Ron 

Looks like I am a lucky one as my foamies only ever go into the ground at 20mph max  Unless of course its an RX fault, and then it goes in the bin anyway 

i like to get the jart slope soarer up high(dot) then dive down to the slope pull up and hug the ground all the way up the slope but many a time i get it wrong 
Ron

the only rx i have had fail in a long time has been a new one on its first flight
if i was to deck my 26cc extra hard (bin bag) i would not trust it to go into another same size model if it still checked out it will go into an epp model
Ron  

OUCH, sorry to hear that  

This thread just goes to show that many people do different things with RX's after a crash, be them right or wrong  

the only rx i have had fail in a long time has been a new one on its first flight

The only RX I have had fail had a fault from new. I think it was a Futaba 138 DC but I spotted an intermitent fault on the ground doing a range check with the engine running. The RX was sent back and apparently the problem was a dry joint on the soldering of the crystal holder.

OUCH, sorry to hear that  

This thread just goes to show that many people do different things with RX's after a crash, be them right or wrong  

another thing that comes into play is cost if you are on a very very tight budget as many are at the moment
Ron

Tell you what. Since we both know its bad practice to fly on potentially damaged radio gear without first having it checked over by an approved agent. Why don't you delete your posts relating to this effect and I'll do the same with mine. This way new comers who don't know or are uncertain of what should be done after a serious crash wont be misguided into thinking its ok to test it in an old model?

tell you what...

no 

new comers don't have old hacks anyway 

the forces on a rx in a crash can be quite large, but each component is very light, so the force quite low.
why should i send back an rx only to get a 70 quid bill? if it has a new crystal, passes the ground running test, range tests and then flight tests why not use it?
i've never re-used a crashed rx in a show model, which means mollys actually gone through about 5-6
i have 5-6 other planes with perfectly working rx's

Well, I think it is only fair that I offer my services to help to settle this argument.

If any of you have any Spektrum rx's that you've crashed and are unsure about using, please send them to me. I'll test them out and, if they work ok, will use them in my fleet, thus negating any of your worries about using suspect gear.

Can't say fairer than that.

Well, I think it is only fair that I offer my services to help to settle this argument.

If any of you have any Spektrum rx's that you've crashed and are unsure about using, please send them to me. I'll test them out and, if they work ok, will use them in my fleet, thus negating any of your worries about using suspect gear.

Can't say fairer than that.

  That made i larffff

Just trying to provide for our little community by offering my services. 

This kind of selfless sacrifice doesn't come lightly, you know.

Generally I'd prefer to have equipment from a crashed model fully checked out prior to re-use in another airframe.

It's a common sense thing really. If a model has a rough landing, but nothing is cracked or broken then I'll usually go ahead and fly again. However, if there is airframe damage, then I tend to assume the worst and have the gear checked over.

What price safety and peace of mind?

...its bad practice to fly on potentially damaged radio gear without first having it checked over by an approved agent...

  erm, what exactly do you think the 'approved agent' does with a surface-mount receiver with no tunable components?  And then, do you think they take them out in the open and do a full range check, as you would?  Call me sceptical...

Mark, you'll be busy with all the crashed spekkys, so if you like I'll take all the cast-off FASST receivers. Deal?   

Phil

Sounds like a plan to me! 

I remember many years ago Model Avionics used to test "serviced" and "post crash check" equipment on a vibration table looking for interruptions in the output signals - the M-series receivers were prone to cracks in the PCB tracks in a couple of places, and often a crash used to fracture the solid wire link from the upper side of the Xtal socket to the board. But I don't think many do more than a bit of a soak test these days.

PDR

i'll take all 35mhz rx's please 

 A very interesting thread indeed. PDR mentioned what used to be done at Model Avionics, but now suspects all they do is a soak test. After two complete loss of control episodes. I sent my T/X to HH, who returned it with a note to say 4 hour soak test carried out NFF. Not sure exactly what "soak testing" actually is, if just leaving said kit switched on for 4 hours and givimg it a stir & prod now and then, well could do that meself and it does little to inspire confidence in the NFF finding. In my original posting a fault was found with the gentlest of touches to the PCB of the R/X, a soak test would not have revealed that IMO. So unless someone at HH is reading this and can enlighten us, what's the point of returning suspect gear to the recommended repair depot ? 

i always thought a soak test meant they chucked it in a sink and see if it still worked 

i always thought a soak test meant they chucked it in a sink and see if it still worked 

Wet or dry sink though . You're just trying to up your postings count aintcha 

you think i need to? 

 No, but I do, hence the flippant remarks

I sent my T/X to HH, who returned it with a note to say 4 hour soak test carried out NFF. Not sure exactly what "soak testing" actually is, if just leaving said kit switched on for 4 hours and givimg it a stir & prod now and then, well could do that meself

My point exactly. I very much doubt they have the equipment to do any real testing on 2.4 stuff, professional microwave test gear is very expensive, and ultimately, (other than the blown tant through polarity mistakes) you cant usually mend these things anyway.  I really think ( IMHO) you will probably test suspect gear more thoroughly than they will. When I worked in BT's radio & electronics repair centre we had to do the same, there wasnt the time to search all day for intermittents, if it worked for a 10 minutes it went out.
Cheers
Phil

Well, I think it is only fair that I offer my services to help to settle this argument.

If any of you have any Spektrum rx's that you've crashed and are unsure about using, please send them to me. I'll test them out and, if they work ok, will use them in my fleet, thus negating any of your worries about using suspect gear.

Can't say fairer than that.

Should you get snowed under with this very kind offer, I'll happily take any that are in excess of your needs. 

No sign of a postie laden with little parcels yet, unfortunately.....

Soak test is just that - leave it on and see if it fries - not really very helpful.

In the 'bad old days' when you whacked one in, all the little descrete components would be leant over at 45 degrees - today we have surface mount circuitry, so physical stress from G forces is much less (by a massive margin)!

But the wires - the plugs - the sockets and cases - the PCB and so forth will still break - poking and prodding - bending and leaning will show up faults more effectively!

I whip the RX out of the case and inspect it physically to start with - then it's connected up out of its case and given the prod and poke test, if I can't induce a failure with 'severe' stress tests it's probably OK.

And a brand new one is also only 'probably' OK!

"And a brand new one is probably OK too."    Yikes Torques, do you know some thing we don't ? I agree with the rest of your posting though, bang it about a bit, sticky fix it to the washing machine at max spin, (ours tries to waltz across the kitchen and down the garden path, I have a hell of a job getting her indoors off the bl**dy thing !)   If it works okay, into a hack for an airtest, sorted.

Do you want the "Reliability Bath-tub curve and PRAT proving" lecture now, or shall just take it as read...

PDR

  What ? Not sure how to take that.

if your really bothered, take a small motor and fit a wheel collet with a bit drilled out, attach it to a bit of 4"x4" ply
put some velcro on the top of the wood so you can stick your rx to it.
get some m3 bolts and drill 5mm holes in each corner along with some in a thicker 5"x5" wood base
fit bolts through the base with washers, and nuts, then the silicon and then the ply top and loosely put some nuts on to hold it all together.
connect the motor to a small power source, 1.2v ought to do it, enough to make a good high frequency shake, not a jumping bronco
now test your rx on the vibrating table till happy.

  What ? Not sure how to take that.

"Production Reliability Acceptance Testing"  - the process used to shake and bake out the infant mortalities in manufactured equipment.

PDR

"And a brand new one is probably OK too."    Yikes Torques, do you know some thing we don't ? I agree with the rest of your posting though, bang it about a bit, sticky fix it to the washing machine at max spin, (ours tries to waltz across the kitchen and down the garden path, I have a hell of a job getting her indoors off the bl**dy thing !)   If it works okay, into a hack for an airtest, sorted.

I've lost count of the number of new bits of gear that have either had little bits of wire or solder floating about over the back of the PCB, to loose screws - lousy connections - pulled wires, you name it!

One transmitter I pulled apart had a huge length (about half an inch in old money) of tinned copper wire stuck across the tracks on the main PCB - it wasn't connecting but it could have at any moment - been flying with it for years!

Surface mount technology has improved things no end - same with engines which are now 'clean' inside - it used to be perfectly normal to take a brand new engine apart and clean all the swarf out - not so much now!

Most stuff is pretty good, but with the numbers involved, you do get iffy now and again!

I had a Futaba Dual conversion RX that had a vibration fault from new. When it was sent back they claimed it had a dry joint on the crystal holder. So even brand new RX's can have faults 

Although thats the only one in 20 years and I guess I have owned over 100 RX's in the time and maybe significantly more with the majority being Futaba