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Jan 27, 2015, 02:18 AM
My 1st R/C had 2 valves !
KraftyOne's Avatar
Quote:
Originally Posted by ivanc
ANY transmitter using PPM can be converted to 2.4GHz. Even if the PPM is not "standard" it can be adjusted by changing components. BTDT.

The real question is "Would you use an old transmitter even when converted to 2.4GHz to fly a model aircraft?"

Ivan
Yes certainly, see post 136 above....

And now at last "The Beast", (my Linux workstation) is upgraded with some (new for it), but well used hardware and booted up again, here are the JR receiver schematics.

Cheers, EGB.

Eric from OZ
Kraft Radio Recycler.
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Jan 27, 2015, 04:09 AM
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Condor84's Avatar
Interesting observations ivanc. Oddly enough, my 8U Super (one of my all time favorites), has very good repeatability, and centers every time, on both FM and 2.4, Well, except for a few real bargain bin servos, but it's to be expected with a 2 dollar servo. Makes one wonder about gymbal/potentiometer variances amongst even newer generation radios. I know guys who have the Aurora 9 that have even had problems with centering, yet haven't experienced it with my unit.

Now, my Hitec Challenger 455..that's a completely different story. I've seen better gymbals in some $10 dollar rtf helicopter radios! I know it was the 80's, but geeze.. I've never heard gimbals squeak this bad, even after being set up and lubed. Everything's plastic in them, except for the non adjustable tension springs, but maybe those should have been as well. If you want a well centered servo with that radio, you're better off throwing it against the wall a few times and hoping it centers itself. Though I am guilty of flying some beaters with it, I'd never trust it with anything worth more than a few dollars, or flies so slow that it doesn't matter much. First flew the radio in a Goldberg Electra as a kid, and was very happy to go back to my Conquest after that one. That poor Hitec makes my dumpy old Conquest look like a gold plated 9ZAP in comparison.

Also, another question for you guys. Anyone have any experience with the M.A.N 2-3-4? I always thought they looked very cool, but never met anyone that built or used one. I've been hunting one out, even if just for the cool engine turned case.
Last edited by Condor84; Jan 27, 2015 at 04:22 AM.
Jan 27, 2015, 06:28 PM
Registered User
what I know about Electronics is to use the switch to turn it on an off
make dam sure it has NEW battery's an are in there correctly
but I would like to take an 71 or 73 Kraft Sport Tx
an make it spectrum 2.4 to fly my EPP foamies
like my Dx6i
Jan 27, 2015, 09:29 PM
Registered User
Jet_Flyer's Avatar
An ACE R/C Digital Commander 1 - 8 kit built in 1977 with kit ACE servos kit built.

Mike
Last edited by Jet_Flyer; Jan 27, 2015 at 09:36 PM.
Jan 27, 2015, 10:10 PM
My 1st R/C had 2 valves !
KraftyOne's Avatar

Tower mystery solved?? (almost).


Hi Condor,

When you posted the pics of your Tower radio, I noted the "Consumer Hobby Corporation" label, which I took to be the Holding or Parent company of Tower Hobbies, but I was just jumping to the wrong conclusion again, (must stop doing that).

When I read a model mag, it's not to read the ads, other than ones from the major and minor MANFACTURERS, the MARKETING ads I just flip straight past. While looking thru an RCM from December 1980 today I spot a banner in the corner of a 2 page marketing spread, "Consumer Hobby Corp. CHC".

So there you have it, your Tower Tx is most certainly made by Kraft, the servos are from Dunham. the only question now is who made the receiver for CHC. The only one I definitely KNOW used the Deans 3 pin system was Proline, but here were probably many more.

Cheers, EGB.
Jan 27, 2015, 10:35 PM
Registered User
Condor84's Avatar
Holy Bejeesis! You've made my week. What a find! Thank you very much. We may never know who made the receiver for CHC, but I'm ok with that.
Jan 28, 2015, 02:22 PM
Registered User
Condor84's Avatar
I wonder though.. if I open it up and take a picture of the board, maybe some enterprising electronics expert might recognize the layout and component selection and be able to narrow it down to who CHC at very least took the design from. It'll have to wait until tonight though because the wife has my camera at her pre-school class today.

Don't worry, she's not in pre-school, although sometimes I think she should be; she's actually the teacher..haha.
Jan 28, 2015, 02:28 PM
Registered User
Condor84's Avatar
Quote:
Originally Posted by Marty Slater
what I know about Electronics is to use the switch to turn it on an off
make dam sure it has NEW battery's an are in there correctly
but I would like to take an 71 or 73 Kraft Sport Tx
an make it spectrum 2.4 to fly my EPP foamies
like my Dx6i
Also, if you get around to doing this, I'm sure I, as well as others here could help you do it; If you just wanted to convert the basic radio to 2.4 the only things needed would be an old Kraft Sport (if that's what you'd want to use), a Spektrum module (either knockoff or legit), some good wire, and of course the normal soldering equipment and basic tools.. and a little bit of time and knowhow. It really wouldn't be too too hard if you already know how to solder. Odds are, you wouldn't have to chase down a good PPM signal for the module because either someone here knows where to use it off the board, or if it's the same board as mine, I already have the info.

Now, if you wanted to have it converted to a full computer radio.. well, can't help you there, but KraftyOne would be the one to start asking.
Jan 28, 2015, 05:53 PM
My 1st R/C had 2 valves !
KraftyOne's Avatar
Condor, check out Jet_Flyers post 154 showing the Ace R/C receiver. It reminded me that they also used Deans 3 pin connectors. We could possibly get clues from similar photos of your CHC.

Some of my mates built the RCM Digitrio when I was still fiddling with my analog propo stuff, but I don't remenber seeing any M.A.N. 2-3-4 digitals down here.
Jan 28, 2015, 07:07 PM
Registered User
Condor i got 3 Kraft Sport Txs 1970 or 73
just the basic radio to 2.4 i also have 2 Dx6i that i normally fly with
just thought it would be a hoot to fly my EPP biplane with my old Kraft
where would I get the Spektrum module an how much
on another note Condor you were talking about an article in Dec 1979 AMA
about how to add dual rate control to your Tx in the March 1980 there is a follow up article
on adding Roll Right
Marty
got to let my 1 finger cool off from all this pecking
Jan 28, 2015, 08:19 PM
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coriolan's Avatar
Marty

You can use this DIY module to convert your Kraft Tx, just need V+,ppm and ground connection(it does DSMX and DSM2):
https://www.hobbyking.com/hobbyking/s...er_Module.html
Jan 29, 2015, 12:21 AM
My 1st R/C had 2 valves !
KraftyOne's Avatar
Quote:
Originally Posted by Marty Slater
Condor i got 3 Kraft Sport Txs 1970 or 73
just the basic radio to 2.4 i also have 2 Dx6i that i normally fly with
just thought it would be a hoot to fly my EPP biplane with my old Kraft
where would I get the Spektrum module an how much
on another note Condor you were talking about an article in Dec 1979 AMA
about how to add dual rate control to your Tx in the March 1980 there is a follow up article
on adding Roll Right
Marty
got to let my 1 finger cool off from all this pecking
The old Sport 5 was different to the std Krafts sets of the time, it was first Tx to use an IC encoder, and used a center tap in battery pack to provide 5V (approx) to run the logic section. 2.4Ghz modules only need 5Volts too, so this all you would need in a converted set.

BUT... there are a few things to consider.
It would not be able to be used with the small BNF foamies, the channel order will be different, and possibly the control directions, and there is no servo reversing. If your models have separate receivers and servos you can re-plug the servos, to the correct channels, but may have to change the linkages if the directions are wrong.

I havn't looked inside a Sport 5 for over 30 years, but you have sparked my interest. I have one in the back of the shed somewhere, I'll dig it out, fire it up and see what is needed for a conversion.

EGB.
Jan 29, 2015, 07:41 AM
S.A.D. member
ivanc's Avatar
Channel sequencing and reversing is not an issue - the transmitter pots can be rewired to match the BNF sequence and direction - all BNFs are the same in that regard.

Ivan
Jan 29, 2015, 12:33 PM
Registered User
Quote:
Originally Posted by KraftyOne
Yes certainly, see post 136 above....

And now at last "The Beast", (my Linux workstation) is upgraded with some (new for it), but well used hardware and booted up again, here are the JR receiver schematics.

Cheers, EGB.

Eric from OZ
Kraft Radio Recycler.
Thanks Eric, I'll check them out after cleaning up an old Nitro 4WD car my son gave me. It looks like it's the second one as it has 10 transistors, the other 2 have more.
I need to correct that, It has only 9 transistors, I was counting the BA707 as a transistor, so it is different to these ccts, hopefully they will be a bit of a guide as there are many similarities.
Mike
Last edited by robinhood; Jan 29, 2015 at 12:50 PM.
Jan 29, 2015, 01:53 PM
Registered User
Condor84's Avatar
Krafty, ivan, and coriolan all beat me to it! I second the OrangeRX module for pure cost effectiveness, however for a few dollars more, I remember seeing a couple Spektrum DM-8 modules for around $50 a piece on ebay new, minus the receiver that could easily work.

Also, with the OrangeRX Spektrum module, you can buy an additional programming "dongle" to be able to correctly map the channels for the BNF aircraft, but for the extra price it may not be worth it, as it only corrects to Futaba, and I know that my Tower actually has the Elevator and Aileron channels reversed, which is a different order from most radios I've seen.

But Ivan is right. You could rewire the pots and their placement on the board to correct for servo reversing and order if you didn't want to do it on the airplane side, as I know a lot of the BNF airplanes can be a pain to get into. Although, if you hate re-wiring, it may not be a bad option to do it airplane side, but you may still need to reverse some of the gymbal pots to work correctly with your airplane. And you'd need to change every BNF you want to use, not just do it once in the radio.

I promise, it's not as hard as it all sounds, but does take just a little bit of forethought.

And, Krafty. When I saw a couple pics of Ace receivers the other day, they looked similar to the CHC, but I can't confirm for sure. I was going to take pics last night, but I actually fell asleep at 11PM. My DirecTV glitched, and for once the peace and quiet in the house put me right to bed.

I'm a night owl; I have no business being in bed by 11!


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