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It all began when a friend decided to buy me a 'Blade mCX' micro helicopter to convince me that they were a good thing. Unfortunately, he simply couldn't find one with a Mode 1 transmitter (a national epidemic sponsored by the trade). The solution was to buy a 'BNF' (bind and fly) heli and a Spektrum 'DX6i' Mode 1 transmitter (don't you wish you had friends like that?).
The transmitter was almost the perfect gift - something you wanted but wouldn't buy yourself (I don't do enough flying these days). I did buy a couple of receivers so that I could convert some of my existing models.
Things took a downward turn when the heli developed a habit of falling out of the sky. It took a long time to establish that it was the transmitter (I even scrapped a couple of Li-Po batteries). In common with lots of modern transmitters, the DX6i has a monitor screen which allows you to see the operation of all six channels. This showed that the throttle channel was intermittently not giving full throw - in fact, only a little more than half throttle - at full stick. This didn't seem to depend on any other factor like switch positions, etc. My conclusion was that this could be a bad potentiometer on the throttle stick.
Strangely, there was no information with the unit other than the fact that I should contact Horizon in the US for help and an email address. I emailed them with the story so far and suggested that it was a bad pot. After a wait of almost two weeks, I received an email from Horizon UK suggesting that it was a bad pot! My response was that if the best they could do was throw my own ideas back at me, I would fix it myself.
I opened up the case and was literally appalled at the standard of soldering on all the switches and pots. The pots themselves were poor quality and appeared to have old type paper reinforced plastic bases. I had expected at least fabric reinforced (still out of the Ark) or glass reinforced. The soldering on the throttle stick had a tail of solder which shorted one contact to the insulation on the adjacent wire. I removed this and hoped that it had cured things.
Well, it did for a while but the problem returned. I removed the wires from the throttle pot, shortened and retinned them, cleaned the pot contacts and resoldered. Once again, it worked for a while and then started playing up again. While we are discussing the transmitter interior, it is worth mentioning that everything is connected by plugs and sockets. A great idea for servicing, but I have developed a healthy distrust of Chinese clones of western connectors.
I had been using the transmitter to fly a park flyer and started to experience elevator glitches. We are told that DSM2 technology doesn't/can't glitch! One feature of the transmitter access system is a scroll device on the right of the display. When you have the required menu item, you press this and it moves you into the next screen accompanied by a beep. Well it beeped, but it didn't always do anything.
At a local indoor R/C meeting I discovered, totally by accident, that certain Spektrum DX6i's had been recalled because of suspect potentiometers. I was rather annoyed that Horizon hadn't contacted me when we had already communicated on the subject. I discovered a service notice on their website listing the affected transmitters and, of course, mine was one of them. I also found a 'phone number for Horizon UK.
I phoned them specifically to find an address to post it to. After wading through a call centre I spoke to a human being who told me that they would collect it. I was also advised that I should make a note of all the settings as I would get a new replacement. Did they want a list of the problems that I had? No. Federal Express duly collected it on the appointed date, but not until I had waited in until 4 pm.
A week later, I received an email from a Lynne Atwell requesting my address because the address that they had was not my adress. Another week went by and I queried the position and was told that it would be delivered on a certain date. In view of the elapsed time, I am forced to the conclusion that, having collected it from the correct address, they delivered it to the wrong one at least twice!
Another day twiddling my thumbs until 4 pm and it arrived. Er, yes, but it was my original transmitter with new stick pots fitted! The sticks were much better quality with epoxy glass bases and the soldering reinforced with heatshrink tubing. I sent Miss Atwell an email stating my unhappiness at the situation, gave them the benefit of the doubt and started using it. I got no response to the email and the elevator glitching returned along with constantly changing trims. 10 days later, I sent a follow up email, again with no reply. Another week went by and I sent an email to their sales department requesting some sort of response. This provoked a response from Miss Atwell stating that they wanted another look at it and requesting a date for collection.
Another day of thumb twiddling, but only until 3 pm this time. Nothing for it now but to wait and see, At the end of that week a neighbour informed me that I had received a visit from FedEx at the startingly early hour of 2 pm when I was shopping. She had been unable to intercept the driver, who had almost literally knocked the door and ran. Had I known they were going to call, I would have been there. Now, most carriers in this situation will post a card through the door telling you they had called and giving you various options, FedEx, it appears, return to sender. When they didn't appear on the next working day I queried the above lady and was asked for a date for delivery.
I considered going out for the day and returning just before 4 pm. A good job I didn't, because they appeared at 2.30! I opened the box almost eagerly. There was a nice new DX6i,
I considered having a go at converting it to Mode 1 (which we are told can't be done) but decided there was just too much to do. Anyway, the pots were still the cheap ones that had caused the original troubles and I knew they could do better.
I feel that I should probably apologise for the tone of the email that I sent to Lynne (we've never spoken but I feel we are on first name terms). The response was a request for another date when they would collect one and deliver another, specifically between 9 and 12 am! Astonishingly, there was a knock at the door at 8.30 am (lucky I was up) and the exchange was made. I get the distinct impression that someone was determined to have the last word/act.
If you've struggled this far, let me put you out of your misery by telling you that they delivered a new Mode 1 DX6i with an AR6200 receiver - a bonus. I don't know whether this is a form of payment, a means of shutting me up, or a mistake. Whichever, they needn't have bothered because there is no way I'm going through that again. Something like 6 months overall and about a week waiting for FedEx. If it doesn't work, so be it. Yes, it does have the better quality pots and the heatshrink tubing.
Once again, no UK paperwork, only return/servicing details for the USA. Maybe Horizon UK want it that way.
One final point: As far as I am aware, despits everyone now ignoring the fact, any form of telemetry from a model is illegal in the UK. If DSM2 works the way that the literature would have us believe, the receiver communicates with the transmitter. Draw your own conclusions.
I decided to use that AR 6200 receiver in a new collective pitch heli using the 3 servo CCPM set-up available in the DX6i. I found that this receiver is very critical of the switch on sequence. Having bound the receiver to the transmitter, I ound that it would not recognise the transmitter if the 'Hold' switch was on. You can't bind with the switch on because the transmitter won't let you do this. If you then power down the receiver and then power up again, it still won't recognise the transmitter. You have to turn the transmitter off, then back on, and then power up the receiver with the hold switch off. The Hold switch is a valuable safety feature which helps when starting up any electric model. It is also clear that the two receivers which form the AR6200 package will 'find' the transmitter at differing times. Sometimes, one won't find it at all. My other receivers produce a 'beep' from the ESC when they lock on to the transmitter. This one doesn't.
I tried all my other Spektrum receivers - Blade mCX, Ember 2 and two AR 6100 receivers will all happily recognise the transmitter whether the Hold switch is on or off.
This particular heli has a gyro that needs several seconds to find neutral and enable itself. With a 35 Mhz receiver this takes 10 - 12 seconds. With the AR 6200 receiver it can take up to 3 minutes! When setting up the collective I could clearly see that the three servos were not working together. More seriously, the elevator servo would 'freeze' and then suddenly catch up. This doesn't happen with a 35 Mhz receiver. I did manage to reproduce this condition while the transmitter was displaying the monitor screen and there did not seem to ne a matching 'hang' in the elevator channel.
On one occasion, having turned the transmitter off and on - to simulate a failsafe condition - the heli started up and caused minor damage to another model, fortunately without damage to the heli. Aren't we told that Spektrum technology can't do this?
Having now flown the heli with the Spektrum, it does not feel nice at all and it is clear that collective pitch inputs produce unwanted cyclic inputs. So, I decided to revert to a JR 35 Mhz system. Having now flown this set-up, its a different helicopter! One more nail in the DX6i coffin.
One final question: Would YOU fly a large powerful IC powered model using a transmitter which had 4 pencells clipped in the back of it? In my view, the DX6i is only suitable for indoor models or very small, light, park flyers.
This transmitter is currently hovering about six inches from the nearest wheely bin. The AR 6200 receiver is rather closer.
