Modifying the DX7 - combined

[Pierre Marais]

How about the LiFe transmitter packs (e.g. Hyperion)? On paper it seems like a good option.

[trevor grace]

can i make the flight time alarm LOUDER as im a deaf old git  < wifes description!!!!!!!!!!!

trevor g 

 

[trevor grace]

got all excited there  

forgot to say the Tx is a DX7

 trevor g

[trevor grace]

is anybody there !!!!!!!!!!!!!!!!!!!!!!!!

trevor g

[Pete B]

I'm sure Timbo must be otherwise engaged or he'd have been here by now, Trevor. A while back he showed such a device for a Dx6i in this thread.

 

It's mentioned in several parts of the thread.

 

Whether it will work with a Dx7, I don't know. 

 

Good luck!

 

Pete

[Tim Mackey]

Trevor - I have already replied to you on another thread mate!

[Tim Kearsley]

A dire warning to anyone doing the new voltage regulator mod!!!!

 

I started to do this mod this morning.  I thought it would be good to measure the current consumption of the DX7 before I replaced the regulator, and then measure again after the mod.  So I unsoldered the positive lead from the battery input and put a current meter inline.  I switched on the DX7 - all fine, except the current was greater than the full-scale on the meter.  No problem so far, but then I disconnected the meter WITH THE DX7 STILL SWITCHED ON!!!!  Yes, I realise it was daft in the extreme, but I didn't appreciate that it screws up the DX7 entirely!!  All I get now is the dreaded "BACKUP ERROR" if I power up the DX7, and from what I read, this entails a trip back to the factory to correct.

 

So just beware, DO NOT disconnect the battery from the DX7 with the power switch on.  I'm sure most of you are far smarter than me and wouldn't, but of course letting the battery drain completely with the Tx on could have the same effect.

 

I think I'm not going to be flying for a week or two now.....

 

[trevor grace]

Thanks for the warning Tim

YOU ARE A STAR 

[Tim Mackey]

Tim, have you tried entering the hidden service menu to see if it will reboot?

Incidentally, I HAVE let mine drain completely whilst switched on, and it had no ill effect at all - other than on my wallet when I had to replace the battery

( thats why I then went on to fit the LV alarm microscreamer ) 

[Tim Kearsley]

No, it won't go into the hidden service menu Tim - you get the same BACKUP ERROR message displayed and nothing else.  All I've read online thus far indicates a return to HH is required

 

Interesting that you didn't suffer the same problem when the battery drained.  From what I've read, it seems that the CPU can end up overwriting flash memory with rubbish if it loses power while switched on, hence the "backup error" message.  I think a side-effect of this is that all programming of models in memory is lost, so I'll have that to attend to as well when it returns from repair.

 

Anyone know what the average turn-around time from HH is for repairs?  Also what cost I'm likely to incur?

Edited By Tim Kearsley on 05/09/2010 20:12:22

[Tim Mackey]

Oh dear, thats a shame. All experience I have had with service turnaround from HH is excellent - usually a week at most - and as for charges, I have never had any !

Best of luck

[Tim Kearsley]

Actually, what I said isn't true - it will go into the service menu, I've discovered.  However, I haven't been able to do anything useful once in it!!  If I select the "Reprogram" option nothing discernible happens and I'm faced with the same BACKUP ERROR message on next power-up.  If I select the "All settings OK" option I get a recognisable display, but, again, on next power up I simply get the error message.

 

Your experience with HH is encouraging Tim - thanks very much.

[Tim Kearsley]

Just to round off my little saga with the BACKUP ERROR on the DX7 - I got it into the post  to HH late Monday afternoon and it was waiting for me when I got home today, Wednesday!!!!  Now is that service or what?!!!  What's more, there was no charge.  I think it's just exceptional, and I will be posting on the Retailers/Distributors thread just how good HH's service is.

 

So, I'm back in business, much wiser now of course about not removing power with the switch ON!!

 

[Tim Mackey]

Great news Tim - and another example amongst many of the excellent service from HH.

Did they not make any comment about you having changed the regulator 

[Tim Kearsley]

They did not Tim - mainly because I haven't done it yet!!!  I'd managed to screw up the DX7 before I'd done it, so thought it wisest to leave things alone until I'd had it repaired.  Not TOTALLY daft you see!

 

All I've got to do now is set all the models up again.....

 

[Lazygit]

I would be very wary about fitting switching regulators to radio gear for aircraft. You may not have a problem, perhaps for months, or even longer, BUT linear regulators are used with good reason, in particular,  they do not generate noise. The switching regulator is an inherently noisy beast, and though the radio link may not suffer, there is plenty inside the transmitter which works at frequencies which could be affected by noise.

If the regulator in your deaktop causes a problem it's a bit of a nuisance, if the regulator in your transmitter causes a problem, someone could get seriously hurt, not to mention the out of pocket expenses.

The equipment  as supplied conforms to the CE requirements. If you alter it , it no longer complies. If there are serious injuries involved, you may have questions to answer, and I wonder how the BMFA will deal with the insurance liability.

The manufacturers would probably have fitted switching regulators if they were ok.  Being able to advertise their transmitter would last all day even if you left it switched on, would be a good selling point.

[Tim Kearsley]

My guess would be that the reason linear regulators are fitted rather than switching regs has far more to do with cost than any technical reason.

[Lazygit]

We can all guess, but in the quantities manufacturers buy, the difference will be small, and given that marketing budgets are enormous compared to the engineering budgets, the marketing department could recover the extra cost by selling the benefits of a much longer battery life. After all, the manufacturers don't have much trouble bringing out  a more featured and more expensive build new model.

Never the less, by making these mods, your equipment is no longer CE compliant. Have your changes been tested to ensure there are no adverse effects?

[Tim Kearsley]

Well the mod in question is quite widely published on the Internet and this thread alone has seen people perform the mod much longer ago than I have.  I would presume from this that it has been tested by quite a few people over quite a period of time. To date, I haven't heard of one report where any issues have been attributed to it.  As for injuries being caused by it, well, I personally think that's stretching things a bit.  If a model goes out of control, how, exactly, would you attribute the cause to interference caused by a 3.3V switching regulator inside the Tx, amongst the myriad of other possibilities?

 

Mountains and molehills come to mind.

 

[empeabee]

Ah but the Insurance Companies get rich by nit picking, never mind mole hill poking...

My farthings worth

Mike 

[Tim Kearsley]

Life's full of risks, and the risk of having a huge payout because I injure someone because I fitted a new, more efficient voltage regulator in my transmitter is one I'm quite happy to take!

 

[Tim Mackey]

Mines been in a LONG time ( over 3 years )  and is still fine.

Cumulative hours used? ....gawd knows, but into the 300 hundred + I would guess.

I cant see how the frequency of a switching regulator is likely to a concern in a 2.4G set...and I suggest the reason the standard unit is linear, is more to do with cost !

[empeabee]

Linear V switching.

The stock reply is noisy power lines from switchers.

This could cause jitter on the analog / digital conversion if care had not been taken to filter the analog supply.

But I think it is a result of taking a stock vhf tx and adding the 2.4gig stuff - stepwise development, followed by If It Aint Broke, Dont Fix It thinking by the production people - like why stuff a 9,6v battery into a 3,3v system - cos its known to work and 9.6v packs and chargers are both mature technoligy - thus cheap.

Go buy a 3.3v 1Amp linear regulator - £0.50 in ones,  Switchmode £12.00 or so - retail, All mfg plants must have thousands of 3.3v linears so they will be effectivly free, and known to be very reliable with very very low Dead On Arrival fugures - great for production.

Time will see improvements, but only if the is a real need.

Just Good Enough is the best production model.

 

Mike

Edited By empeabee on 13/09/2010 01:43:37

[Tony Smith 7]

Posted by Lazygit on 10/09/2010 21:44:17:

Never the less, by making these mods, your equipment is no longer CE compliant. Have your changes been tested to ensure there are no adverse effects?

Maybe someone can clarify, but I'm not convinced that CE works like that.  If I understand correctly the CE mark means that it complied with the appropriate standards in force at the time it was sold.   Given that everything is CE marked nowadays, I'm sure it can't possibly be illegal to modify something with a CE mark.