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Frsky Problems?

PostPosted: Mon May 17, 2010 6:18 am
by swarrans
In the interests of balance, which is what this forum is all about, I'm a keen buyer and user of Frsky 2.4 radio in my Futaba FF9 but I have lost 2 nice models that have been confirmed as Frsky receiver failures by the UK Dealer.

I'm still keen on Frsky and want them to succeed, but it has rocked my confidence a bit, especially using them in something nice (I've just got a 5.4m MDM Fox glider and it won't be going in that!).

The failures are especially baffling because the receiver had functioned OK on numerous flights and also for about 15 mins on the actual flight when the failures occurred (I realise some of you will be sure it is a battery problem not the rx but trust me it has been fully checked and the UK Dealer has agreed it is an rx failure).

Basically, on both occasions the rx shut down completely and did not go into failsafe mode (even through it had been set and checked) - unfortunately both times it seemed to fail in "down" elevator and so the models came in vertically (you can catch the last moments of my PSS Lear Jet by searching for PSS Lear on YouTube!).

Frsky are looking at the rx in China now to see what the problem was - I'm not posting this to scare anyone off the system because I still think it's great and Frsky and the Dealer could not have responded more openly or positively (imagine Futaba/JR admitting they had a problem?!) but I think I will be using the receivers in foamies or something not too precious for a while...


Re: Frsky Problems?

PostPosted: Mon May 17, 2010 6:24 am
by RCModelReviews
Thanks for providing the information -- I know that the UK FrSky dealer is a straight-up guy who will take care of you.

It's a sad fact of life that nothing's perfect and given the numbers of units that FrSky have been selling, it's to be expected that some dud units would turn up eventually -- just a shame it was you who had to find them.

I'll keep an eye on things and if there appears to be a wider problem, I'll let people know -- which is more than Spektrum have done with the AR500. It seems that faulty receivers have no respect for brand-names either :-)

Re: Frsky Problems?

PostPosted: Tue May 18, 2010 7:38 am
by RobC
I've had one fataly failing receiver which went intermittent on channel 6. I sent it back to GC and John diagnosed a dry soldered joint. Very hard to spot, I'd already checked the connector pins without spotting anything. I guess it's a risk with modern surface mount components and lead-free solder, with the old discrete cmponents you could usually spot the bad joints around component leads where they pass through boards.
More of a nuisance is that out of one batch of 8 channel receivers, three smoked their smoothing caps, easily replaced but it's annoying that it happened in the first place. They didn't go straight away on, but after several minutes under power.

Re: Frsky Problems?

PostPosted: Tue May 18, 2010 8:13 am
by jomarx
Hmmm. Sound familiar.

I'ved had my my 8ch FrSky RX fail on me, BUT it might be my fault though...

After repeated hard landings (a.k.a. crash :D ), my 8ch FrSky RX stopped working. Its LED keeps blinking red. I can still do the binding process (green light on on hold of button) BUT I still get the blinking red light error, and my servos are placed in its max position. At first It might be an antenna related problem (I made a thread a few days ago about one of the RX's antenna getting disconnected). BUT after careful inspection, I'ved found out that one of the SMD parts (encircled on the attachment) got disconnected (thankfully only one solder points got disconnected). So after using a magnifier (its so SMALL!) and a SMD soldering iron, I was able to fix/resolder it.

I think vibration might be the cause of the SMDs falling off the board....

Re: Frsky Problems?

PostPosted: Tue May 18, 2010 8:22 am
by RobC
hmmm, receiver fails after repeated crashes? Now why doesn't that come as a surprise? SMT components in general seem more resilient than the old wire mounted components, but there is a limit to the amount of abuse they can stand ;<)
I think we are really questioning equipment that fails under normal use, and plowing a field with the model can't be construed as normal use, can it? Saying that, I did use one model to drill a new hole in the local golf course 7th green, and after replacing one aerial it appears to be as good as new. It'll go in something small and disposable for a while until it's proved itself! The strange thing is that i found the aerial wire in the wreckage, but the U.FL connector was nowhere to be seen.

Re: Frsky Problems?

PostPosted: Tue May 18, 2010 8:30 am
by jomarx
Good point, but the thing is, I only use that RX on DIY foamies... A PizzaBoxFlyer and a Oversized Lightflight R/C Bug clone to be exact....

And which reminds me, there was a plastic part on the casing directly on top of the part of the RX board that got damaged... Ithink its the one that caused the breakage.

Re: Frsky Problems?

PostPosted: Tue May 18, 2010 8:35 am
by RCModelReviews
I've been flying the snot out of several FrSky receivers (in my DLG, my Flying Trainer, a very light 3D profile with a bone-shaking Saito 100 4-stroke up front and another 3D profile with a .46 -- plus a pulsejet powered model or two) and so far, not an issue.

Nothing's perfect and, so long as you ship enough units, some will fail in some way or another.

I've had Corona stuff arrive DOA, I've got a FlyDream receiver here that up and died for no apparent reason and have had faults in 72MHz receivers from Hitec and FMA (both reputable brands).

I'll be keeping an eye on FrSky though, to make sure that they're not rushing stuff out the door too quickly as demand grows.

So far, so good though and now there are a total of about 15 FrSky receivers being used at our local club with no issues to date.

Re: Frsky Problems?

PostPosted: Wed May 19, 2010 10:25 am
by JMP_blackfoot
RobC wrote:I've had one fataly failing receiver which went intermittent on channel 6. I sent it back to GC and John diagnosed a dry soldered joint. Very hard to spot, I'd already checked the connector pins without spotting anything.

Same problem I have had with my 4-channel RXV8R4 receiver.
I found that channel 3 was intermittent.
Upon inspecting the PCB, I concluded to a microfractured solder joint on the
servo pins, even though I could not see it.
I redid all the connector solder joints, top and bottom of the PCB, and the problem has gone.

This problem typically occurs when the pins are snipped after soldering, putting stress on to the solder joint.
The cure is to reheat the solder after cutting the pins, or to cut the
pins before soldering.