Wanted Kraft schematics

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ShowMaster
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Wanted Kraft schematics

Post by ShowMaster »

I bought several Kraft TX's at a rc swap meet and plan to instal Frsky DHT DIY's. These don't seem to use any regulation for the logic circuits and the only IC is not regulated either. I did have schematics in the past but gave them away with my Kraft gear many years ago. These TX's are series 78-80 era open gimble. Finding the ppm line will be easy but I'm concerned about the unregulated logic power buss comming from the 9.9 v battery. I also understand Kraft put out a CD with all the manuals and schematics for many years and models. Any chance anyone has a copy?
I plan to let younger flyers as well as old timers at the field fly the past. I have a single stick as well that I modified but may have some issues so it's getting some more work done on it.
Any manuals or schematics info would be great.
Thanks
SM

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GrootWitbaas
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Re: Wanted Kraft schematics

Post by GrootWitbaas »

Not sure but may have a look here and here .... Not sure this is what you need/want but at least a starting point :D

Also some info on them here (some pictures of older schematics)
General trouble maker and wannabee Dev
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ShowMaster
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Re: Wanted Kraft schematics

Post by ShowMaster »

GrootWitbaas wrote:Not sure but may have a look here and here .... Not sure this is what you need/want but at least a starting point :D

Also some info on them here (some pictures of older schematics)
Thanks it's a start. There were many variations of the Kraft encoders over the years all mine are the gold metal series. I have a good scope and remember enough to sort through the encoder adjustments and I'm going to add a regulator to keep the buss at 5 volts or at least the PPM out. I didn't do that to the single stick and it gets wierd if the tx battery is fully charged. sure a lot going on in the box for a 33 year old TX.
Not much posted on the Internet and the CD with everything on it is real scarce.
I hope to gather as much info as I can before I forget what I do remember.
Kraft died in 2006 I think and Jerry Pullen who sold me my original schematics and manuals I think is gone also.
I flew with Kraft, Joe Bride, and Bill Cannon. Also John Perry when he was developing his carb. Jim Odino of S&O radios still flies at our field. Great people, great times, exciting technology for its time.
I hope to bring back some of that equipment back to life on 2.4 for many to try it.
SM
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Kilrah
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Re: Wanted Kraft schematics

Post by Kilrah »

FrSky transmitters can take anything between 6 and 13V, so no problem there. Module slot power isn't regulated either on any module-based radio I know. There's no spec for the PPM in, but as from looking at the PCB it's pulled down through a "reversed" diode there shouldn't be any issue either.
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Re: Wanted Kraft schematics

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Kilrah wrote:FrSky transmitters can take anything between 6 and 13V, so no problem there. Module slot power isn't regulated either on any module-based radio I know. There's no spec for the PPM in, but as from looking at the PCB its pulled down through a "reversed" diode there shouldn't be any issue either.
Thanks good to know. I sort of thought that but it's good to have a second opinion. I was confused by a fully charged 8 cell nicad pack causing the Kraft single stick to act wierd until it dropped a 1/2 to 1V from being charged. I added a diode inline with the battery and it calmed down but it acted up again later and I put it on tne shelf. Now that I have 2 more similar versions I'll see how they act after I add the DHT DIY and go from there. Having a schematic that's close to the circuits would make it easier to trouble shoot but now I can just compare circuits with my scope.
All my DHT's are 2 way and the newer toggle versions so I'm assured that the Schotky diode is in the ppm input line.
SM

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Re: Wanted Kraft schematics

Post by Crashj007 »

I loved my single stick Kraft, back in the day and always thought it would be perfect for helicopters. Eventually I hope to try one of the modern three axis gimbals.
That Kraft is going to draw a crowd of codgers, you realize?
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Re: Wanted Kraft schematics

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Crashj007 wrote:I loved my single stick Kraft, back in the day and always thought it would be perfect for helicopters. Eventually I hope to try one of the modern three axis gimbals.
That Kraft is going to draw a crowd of codgers, you realize?
I hope so...
I'm looking forward to using one of the Krafts in a fun fly contest and winning. That should draw some attention ha ha.
I've got to get the single stick up and running 100% as it draws the most attention. I just got busy on er9x and ersky9x and forgot about it. Not many tech types to help me out so i have it on the to do list in the next few weeks.
I did find an old file I kept with some Kraft models schematics so hopefully I have enough to work on all 3 if there are any issues when I power the newly acquired 2.
SM
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Re: Wanted Kraft schematics

Post by SR71 »

I have on the highest shelf the my old transmitter bought in the seventies: it is a seven channel 72 MHz AM proportional transmitter, designed and built in Italy by Akiline, a company in Florence (Italy) active till 1981.

Since January, when I learnt of the existence of 9x effort, I am mumbling with myself to reuse the 9x software for revamp this old hardware, using some 2.4 GHz Tx/Rx commodity hardware.

What about create a specific section for retrofit old radio ?
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Re: Wanted Kraft schematics

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SR71 wrote:I have on the highest shelf the my old transmitter bought in the seventies: it is a seven channel 72 MHz AM proportional transmitter, designed and built in Italy by Akiline, a company in Florence (Italy) active till 1981.

Since January, when I learnt of the existence of 9x effort, I am mumbling with myself to reuse the 9x software for revamp this old hardware, using some 2.4 GHz Tx/Rx commodity hardware.

What about create a specific section for retrofit old radio ?
There is a place I think under hardware and mods that a section could be created. Anyone of us can start the section. If you would like to just create it and we can add our radios to it. I didn't check so maybe there is one?
The Frsky DHT DIY is the best of you have no plug in modules the have the JR or Futaba ponouts or no modual at all like my Krafts. The original modulation mode AM or FM is not an issue and ppm polarity is also not an issue. Supply or ppm voltage is also not an issue. Just use a scope to find the ppm signal out and battery power feed. I do have a JR PCM 9 that is PCM only and I'm not sure if it's ever ppm anywhere inside or PCM from the encoder? I know I can't change the modulation in the menu but maybe it's ppm somewhere. These are the TXs l'm looking into pitting on 2.4.
SM
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Re: Wanted Kraft schematics

Post by flybabo »

ShowMaster wrote:
SR71 wrote:I have on the highest shelf the my old transmitter bought in the seventies: it is a seven channel 72 MHz AM proportional transmitter, designed and built in Italy by Akiline, a company in Florence (Italy) active till 1981.

Since January, when I learnt of the existence of 9x effort, I am mumbling with myself to reuse the 9x software for revamp this old hardware, using some 2.4 GHz Tx/Rx commodity hardware.

What about create a specific section for retrofit old radio ?
There is a place I think under hardware and mods that a section could be created. Anyone of us can start the section. If you would like to just create it and we can add our radios to it. I didn't check so maybe there is one?
The Frsky DHT DIY is the best of you have no plug in modules the have the JR or Futaba ponouts or no modual at all like my Krafts. The original modulation mode AM or FM is not an issue and ppm polarity is also not an issue. Supply or ppm voltage is also not an issue. Just use a scope to find the ppm signal out and battery power feed. I do have a JR PCM 9 that is PCM only and I'm not sure if it's ever ppm anywhere inside or PCM from the encoder? I know I can't change the modulation in the menu but maybe it's ppm somewhere. These are the TXs l'm looking into pitting on 2.4.
SM
Yeah, let's create a section.
I have many vintage transmitters and I really want to give them a new life :)
As for the JR PCM 9, it's quite surprising for me that you couldn't change the modulation mode to PPM.
I have Futaba 8U and 9Z PCM Tx's and I can switch them to PPM mode from menu per each model.
BTW, did you find the old CD containing all the good stuffs of Kraft radio?
Last edited by flybabo on Tue Jun 03, 2014 8:22 pm, edited 1 time in total.
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Re: Wanted Kraft schematics

Post by ShowMaster »

The PCM9 was hard coded and has no ppm option. Futaba also made a few like that about that time. I also have a Circuis Hobby JR Century 7 and an Unlimited 8 TX. Being they use modules they will work with the DJT Frsky.
Hard to believe 1 er9x radio can replace them all! Progress!
No lich on theKraft CD yet. There was one on EBay but it's gone.
Would hese schematics be on the FCC site like the 9x? I assume Kraft had to certify every new model over the years? I'm not sure how to look it up?
SM
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Re: Wanted Kraft schematics

Post by ShowMaster »

.
BTW, did you find the old CD containing all the good stuffs of Kraft radio?[/quote]
About the CD.
I did email a request to one person I found and he's sending me a CD with a lot of info on it. I think it's own collection but I'll know more when I get it. He's asking I'm return for any info I have. I'll repost when I know more and hopefully we can all exchange info we have.
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Re: Wanted Kraft schematics

Post by Malcurin »

Just found this for sale in New Zealand
http://www.trademe.co.nz/toys-models/ra ... 278652.htm
Turnigy 9x with ER9X and back light FrSky DHT 8ch DIY, FLD-02 Telemetry Display Screen
AXN with 6x4 prop .... AWESOME!!!!!!!
Canterbury Sailplanes Jazz 60 and Eraser 60
Dyna-flight Butterfly ( under construction )
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Re: Wanted Kraft schematics

Post by ShowMaster »

I was given a Heathkit 5 ch single stick. It's on 53Mhz AM with manuals. It's eventually going to be converted to 2.4 after the Krafts. This model was the palm sized TX.
So far I'm the only one in my club interested in restoring these old systems do it's slow going.
I have to admit it's fun bringing these back to life again and out of a landfill.
SM
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Re: Wanted Kraft schematics

Post by Crashj007 »

Showmaster, I had forgotten about that one which I had also build, back in the day. I did a lot of their kits.
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Re: Wanted Kraft schematics

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Like you I built many Heath kit systems but for for club members as well as Canon Kits and World Engine Kits but never owned any. It was and still is fun giving them life!
I was a Kraft Gold Medal owner around that time on 72 MHz. I did build sticks and all, several MHz digital systems using Orbit servo cases but 27 was a disaster and 72 came along in a Kraft. I did own a Pro Line and RS Systems as well but never any single sticks. I flew others Orbit, S&O systems, Micro Avionics, EK Logictrol, and then the first Futaba's came into the picture under cutting all the US made radios. It seems the Chinese are doing to the Japanese what the Japanese did to the US made systems. And so on ....
It's hard to believe that all that "stuff" inside my Kraft TX's has been replaced with a small CPU?
OK, time to get busy making some of these work again. I have to finish up a (X, Frsky Telemetry conversion for a fellow club member then it's Kraft time.
It's fun so tease the new, and older flyers with these strange looking metal boxes.
SM
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Re: Wanted Kraft schematics

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It's fun so tease the new, and older flyers with these strange looking metal boxes.
"Old Codger Bait"
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Re: Wanted Kraft schematics

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All this RC work has paid off over the years. I just got a call to help fix an issue with a robot named Geoff. He's partial to Futaba.
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Re: Wanted Kraft schematics

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I know him, too! Sort of like Jeff Dunham's buddy, eh?
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Re: Wanted Kraft schematics

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Yes but he/it has a real potty mouth!
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Re: Wanted Kraft schematics

Post by Crashj007 »

And Achmed doesn't?
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Re: Wanted Kraft schematics

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I just got a Kraft series 79 open gimbal tx up and running with a DHT DIY Frsky module. I'm going to fly it this weekend to see how well it works in the air and to also tease some old timers at the field. It has a retract switch as well as a snap roll button factory mod. There's also some extra switches and pot adjustments on the case top that's got me confused as to what they do? A lot of circuitry hanging from each switch. Anyone ever own this model with these features? I was able to cutout parts of the battery box so that standard 8cell or 1500ma 3 sell life can just be inserted with the back off and not disturb the circuit board mounting. I was also able to mount the led and bind button into what was the tx module. It and the antenna look like they belong there. I'm real happy with the outcome and after flying it I'll be even happier.
Next us a series 78 open gimbal I picked up.
Still have to debug my Kraft single stick conversion since it developed a lot of servo jitter after being on a while, it's not a frsky issue.
After that a Heathkit palm sized single stick conversion to 2.4.
I'm not sure what I'll do with them all later in but it's sure fun giving them life again and showing them off at club meetings and at the field. Younger flyers have never seen these TXs and most enjoy a blast to the past before their iPhones ring ha ha.
SM
If their's real interest in this ill start the topic in hardware I think but wanted to share my progress in reliving/reviving the past while embracing the future with er9x and other great upgrades being gone.
SM
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Wanted Kraft schematics

Post by Rob Thomson »

I would love to see pics on this?


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Re: Wanted Kraft schematics

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I'll get some pictures over the next few days. Where should I post them?
I just opened up tne series 78 box tonight and the encoder board seems to be much smaller and it's 5 ch. The series 79 has a lot going on compared to this 78. No servo reversing switches on the 78.
Smaller battery box so I'm sure it uses AA's instead of 1/2 C's. More of a challange if I go with anything but AA's again space wise. The single stick had room inside on the non stick side for a life or regular 8 cell AA retangle pack so I didn't have to use the battery holder.
I did luck out and get a DVD full of TXs from tne past and earlier from A to Z. Some Kraft but earlier than these models. I hope to add to this DVD and send a copy back as well as get permission to pass it on. It would be great if everyone added to it like a chain letter and sent a copy back and on to others. Of course adding all the great work done on the 9x, mods and stable firmwares ect.
Best would be to make them downloadable. I'll see about permission for that if interested. Somewhere out there are copies of the complete Kraft models maintenance CD's but so far no luck finding one.
I love my 9x but this is a lot if fun also.
I paid to hear Phil Kraft give a banquet talk on his winning his gold medal and developing the Kraft radio. His chief design Engineer Jerry
Pullen had his shop a few miles from where I lived so I was able to get parts, schematics and repair my own crashed Krafts at the time.
He also designed the spinoff PCS system. Fortunately I remember enough from Jerry's help and working on my own radios to be able to get these running again on 2.4 and set the timing if needed.
I actually found a box with original new servo motors, pot elements and replacement pot wipers for the non capacitor feedback servos of that era. That may be trading parts for other parts I need if I can find a large user group?
SM
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Re: Wanted Kraft schematics

Post by Rob Thomson »

How about I create a dedicated sub forum?

'Retro Transmitter Mods' ?

Rob
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Re: Wanted Kraft schematics

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Rob Thomson wrote:How about I create a dedicated sub forum?

'Retro Transmitter Mods' ?

Rob
I'm for it if you are. This is a 9x forum but maybe OK for vintage radio mods since they did get this all going so many years ago.
With the concentration of so many technical types they might enjoy a blast to the past?
BRW I did fly me frsky kraft series 79 tx today and it went great. A little encoder pula centering will be required but that's all so far. Several flew it and enjoyed a taste of history. To my surprise one flyer owns and flys only Kraft radios. He also took a flight. He was so impressed I'm now going to convert a signature series Kraft to 2.4 for him.
I've also been asked to make another club presentation on how it's done. A lot of interest in the past thanks to the DHT DIY.
So...
I'm all for a dedicated topic on this if it's ok with other 9x owners.
SM
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Re: Wanted Kraft schematics

Post by Rob Thomson »

Cool... will setup later today.

I think that like it all not - these forums will end up covering more than just the 9x. With such a large 'technical' user base, it is inevitable!

Rob
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Re: Wanted Kraft schematics

Post by MikeB »

Hear is someone else doing up old radio gear:
http://www.giantshark.co.uk/forum/viewt ... 879#p13879

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Re: Wanted Kraft schematics

Post by ShowMaster »

Hard to find.
Kraft encoder schematic. 1976-1978
http://images.rcuniverse.com/forum/upfi ... o40548.pdf
SM
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Re: Wanted Kraft schematics

Post by ShowMaster »

MikeB wrote:Hear is someone else doing up old radio gear:
http://www.giantshark.co.uk/forum/viewt ... 879#p13879

Mike.
Good stuff thanks Mike.
BTW
I bought a lot of Frsky from GiantCod and they sent me this great Frsky Baseball Cap from Frsky for free.
Everything came in record time and in perfect condition to LA.
SM

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