The dark side of the DX8

[Jonnyheli]

Put them on your DX8 then come back with another picture.

-Jonny

[dauste]

I had the strangest thing happen at the field today. I turned on my trusty DX6i and bound with my Furion 450. I stepped back to spool up and things didn't seem quite right??

The swash was very twitchy and as I upped the throttle the pitch came in very hard. I spooled down and looked at the TX and the display showed that I had model 0 in the memory???

Seeing as there is no model 0 that was very odd! Turned everything off and re-loaded the model and everything seemed OK after. It was a good job I didn't just shoot up like I sometimes do otherwise there could have been a disaster.

I was wondering how this may have happened, then it hit me, the DX6i was going on strike! It is obviously cheesed off with the new package that turned up yesterday!

[Tomstoy2]

Mine got pissed when the dx7 showed up, still is. dropping voltage pretty rapidly when I run it on Phoenix, ( just like the cord plugging into the back instead of the side ), like it wants new batterys. I keep telling it, "what have you done for me lately?"

[lilleyen]

A good point though.
Why does such a high tech Tx have such a low res blocky looking screen?
In this day and age???

[redbird300]

Originally Posted by lilleyen

A good point though.
Why does such a high tech Tx have such a low res blocky looking screen?
In this day and age???

Price and power consumption ? If you pay small money, you get (relatively speaking) small features. The DX8 isn't that high tech compared to the real high tech transmitters out there, it only has a whole lot of features for the money you pay, which is a different thing.

The Futaba 14MZ has a nice screen for example, but also costs 4-5 times as much:

[Tomstoy2]

Someday they will all be oled displays, but right now it still costs too much to make. Give it a few years.

[ragge1]

and the rx AR8000 can only be connected with the satalite remote from a AR8000 won't work with other satelites

[Jonnyheli]

I'm with Raf. The DX8 isn't a cinema. It's a transmitter. The only reason for a screen is to choose the options for setting up the heli and visually see the throttle and pitch curves etc. You don't need anything more than that.

However, they probably will end up with transmitters that can play movies soon, not that we need it. You can already listen to music with the Futaba posted above and it's touch screen.

To be honest, with that Futaba, i'm sure your mainly paying for that display. Sure, it has higher specs. But would you notice a difference from Bert Kammerer flying a DX8 or that Futaba with the same helicopter? I don't know if Bert would notice to much of a difference? Maybe I'm completly wrong but the price on those things are stupid.

-Jonny

[ragge1]

today I send my back to HH for the Airware 2.0 update, as mine was the first batch HS008X and was not possible to update it myself , didn't have any issues with it but thought if I don't do it now might have problems with future update , its still winter and in Norway it rains alot this time of the year , got my DX7 so not disable but gonna miss my DX8

[jperkosk]

Installed yesterday firmware v2.00 and today v2.01 appeared. According to HH a couple of minor bugs fixed, but now they disappeared DSMX/DSM2 binding status from the main screen, I wonder why...

[mukenukem]

Rebind it, then the info should reappear on the main screen. I think you only have no protocol on the main screen if you bound it with one of the first FWs...

[jperkosk]

It's even funnier than that: some of my models display the protocol and some don't, and I haven't rebound any of them since v1.4. I think you're on to something here, that the binding info was lost during one of the firmware upgrades, I'll rebind one of the non-displaying helis to find out.

[redbird300]

More bad news about the DX8, and this is really bad news !

1) The DX8s are notorious for bad rudder and aileron potmeters, many of them have been send back to Horizon, and repaired for free. You’ll find plenty of stories about it, and my LHS also confirmed honestly that he had at least four of them returned since he started selling them.

Well, all my helis started showing irregular taildrift the last few days, left, right, a lot, none sometimes, you name it, it drove me almost crazy. And FBL systems are very sensitive to this, the tail will drift a lot, or even start kicking slightly. A little research revealed the cause: my DX8 had a dirty rudder potmeter, you can see this clearly in the “monitor” screen: the rudder channel should be centered in a clean setup, and always return to zero percent when releasing the rudder stick. It didn’t. Sometimes it did, sometimes it didn’t, and showed a slight minus or plus value when centered. Wrong…

Sending it back to Horizon would take 2-3 weeks, said the guy at my LHS where I bought it. Most potmeters are just cleaned, not replaced. That sounded like a DIY job, lol.

2) The eye on the front for the neckstrap came loose again, so I wanted to secure it permanently with red thread lock. In the mean time, I shortened my custom made alu hook a bit, it was too long, as it was made for the badly balancing DX7.

3) While I was working on it, I decided to replace the two long switches on the front (“flap/gyro” and “aux2/gov”) , as Jerry told us before in this thread.


So here we go again:

I opened the radio like I did before, and started taking away the gimball cage, the small circuit board above it, the bearing mechanism (poing….there goes that f*cking spring again, we’ll put that back later), the thicker stick end or you can’t get the mechanism out, and finally the potmeter which is surrounded by the bearings. Take all of it apart, and you end up with a nicely closed potmeter, in a plastic housing. Take an exacto knife, and try to get the potmeter open, but very carefully so you don’t damage the plastic, it will click open at some point, there are four plastic lips holding it together, you might need to cut the tiniest bit of plastic away on the top of these.






After that, I blasted some kind of special contact spray in the potmeter, right on the carbon track, the product is called “Tuner 600” from www.crcind.com, and is developed for cleaning and maintenance of tuner and hifi components. It doesn’t harm delicate electronic components. Here's a link, it's supposed to be better than ordinary contact spray:
http://www.crcind.com/csp/web/ProdDi...hTBUlDUa8nnj2w--


Here you see the opened potmeter, look at the two parts at the bottom:



After that, I fixed the eye with red thread locker, screwed the shorter hook on, and replaced the two long switches on the front with shorter and better ones, here you see one of them: the blue one is new, not yet soldered, the green one is the old one.



Everything re-assembled:



And totally finished: 2 shorter switches, shorter and firm hook, cleaned rudder pot. A look on the monitor screen showed me that everything is working as it should now, curious how long it will last. anyway, for now it works fine, I will test it with a 450 on a lazy susan tomorrow, but it should be OK. Oh, the red cap on the right switch is there because it is my throttle hold switch.





BTW, some people asked me what kind of microprocessor is used in the DX8: I had a good look today, and it is using a Atmel AT91SAM7S512, the datasheet is here: http://www.atmel.com/dyn/resources/p...ents/6175s.pdf


One last thing: I can tell you that I’m not so pleased anymore about this radio. Doing this yourself might not suit everyone. Glad I kept my DX7, thinking about binding all my helis back to that one, at least it always worked and keeps working without a glitch. Just my opinion of course.

[CyprusDave]

Not good Given the problems with the pots in the DX6i, you would think they would have been extra careful with the DX8, especially as it's about 3 times the price. This is not doing Spektrum's reputation any good at all. No such problems with the DX7, but then don't forget that it's basically a JR TX with Spektrum badge and 2.4GHz TX module.

[redbird300]

It's been 24 hours now since the potmeter was cleaned, and I switched it on and off several times, each time checking the monitor screen, on different model setups, and the rudder channel stays nicely centered, also after moving and releasing the stick. The cleaning seems to have worked.

[jperkosk]

Mine hasn't displayed this problem, at least not yet.
Makes me think seriously about DX10t, though, especially if the setting would be transferable between the two...

[redbird300]

To be honest, after opening it several times now, and having a good look inside, judging the assembly and PCB quality, the overall design and components, based on 30 years of electronics hobby experience, I think I won't buy another spektrum product anytime soon, at least not one that just hit the market. A JR 11X for example looks like a better choice for the moment at first sight, and you can keep the same receivers. Weird looking, which is totally irrelevant btw when it comes to holding your precious helis in the air, and offering DX7 reliability with more channels, T and P curves and curve points than the DX8.

[jperkosk]

Well, there are rumors DX10t will me "macht in Deutschland", remains to be seen if they're true.
Agree with you that DX8 assembly quality is only so-so , but still on par with DX6i.

Dave says above that DX7 (I never owned one personally) was actually a JR built unit, and the lack of DX6 scroll roller that re-appeared in DX8 seems to confirm that. The JR11X indeed looks weird, a guy at the club has a DSMJ version (Spektrum implemented frequency hopping patch to DMS2 for Japanese market but not compatible with DMS2 or DMSX) and he thinks he's got direct-line to God, but what worries me is that something not-so-nice is going on between HH & JR at the moment, with HH pushing DSMX and JR about to release their DMSS system, similar in concept to DSMX but completely incompatible with DSMX, DSM2, and even DSMJ.

All that said for now in the US (probably in entire North America, as Canada and Mexico tend to get bundled in as a part of the same market) seems like all new JR TXs will be sold with DSMX protocol, but will the uneasy truce last, and what about Europe? Sad, really, as it seems that so far the best results were with JR providing the hardware and Spektrum underlying RF technology...

I really think I may give it a shot at DX10t when it appears, but not before I can physically put my hands on it at the LHS...

[Ber60]

Wow I took a peek at the JR 11X , it looks like a robot head with his mouth open, something Jack would put on his face to scare children on halloween.

[Jonnyheli]

Never seen a DX8 in real life. I've had the DX6I and when I upgraded to the DX7 I was amazed at the quality of it compared to the DX6I. And why is that? Because it is a JR radio with Spektrum written on it. I'm glad I have this TX now, I never hear any problems with it. I've never had problems with it either.

I'm with Raf, I wont buy a radio from Spektrum again. When I bought the DX7, I knew it was a JR radio, and when I opened it, I could see that Spektrums radios weren't up to the standard of JR or Futaba.

Btw, if you like the DX7 but want a scroll wheel, JR are bringing out the xg7. It's basically a DX7 with a scroll wheel, the only thing is, it's DMSS which might mean you'll need new receivers