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Help with my Kraft series seventy nine

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Old 07-13-2007, 09:42 PM
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fly_boy_bc
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Default Help with my Kraft series seventy nine

Hello all,



I have a complete Kraft 79 system which has been stickered (Canada). I had to remove the main circuit board to replace the batteries. I had no intention of unplugging any of the headers but after I had finished replacing the batteries and was re-installing the board I saw that ALL of the plugs on the right hand side of the board had come out! I freaked out until I saw that the wires had retained their orientation and so I could get all the plugs back in the correct order with no trouble. When I did so I discovered that there are too many pins for the number of plugs that I have (Some are not used). So I have the plugs in the correct order but I do not know which pins on the board go unused!! Looking at the circuit pattern didn't help me since it appears that all of the pins trace to somewhere.



Is there anyway I could impose upon any of you to e-mail me a picture or diagram? All I need is a pic of the top of the main board (The one with all the board mount pots) with the plugs in.



It is a Kraft Series Seventy Nine 5 Channel. Three pins on the right hand header are not used. I even think I know it is the first three (Closest to the rear of the unit)



Thanking you in advance for any help you can give,

Gary

Fly_boy_bc@yahoo.com
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Old 07-13-2007, 10:03 PM
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Default RE: Help with my Kraft series seventy nine

Fly Boy...

Look up Kraft Midwest in Novi, Michigan. Pete Waters is a Kraft service tech from waaaaay back, and I'm sure he'd be able to steer you in the right direction.

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Old 07-14-2007, 07:15 AM
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Default RE: Help with my Kraft series seventy nine

Hi Gary,

I pulled the back off my fully functional Series 80 5-channel and here's what I see:

The red/yellow/black/orange plug goes into the front-most terminals (closest to the face of the transmitter) with the red wire facing toword the sticks.
The "semi striped" blue/white, red/yellow, orange/black, black plug which exits the rear of the white battery case plugs in directly next to it with no space between the two. The orange/black wire should be closest to the front of the transmitter.
This should leave you with three empty terminals at the rear of the board. I was going to take a picture but misplaced my camera. Hopefully this will get you going.

Steve B
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Old 07-14-2007, 05:23 PM
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Default RE: Help with my Kraft series seventy nine


ORIGINAL: Raintown

Hi Gary,

I pulled the back off my fully functional Series 80 5-channel and here's what I see:


************************************Thank you for going through the effort and small risk!


The red/yellow/black/orange plug goes into the front-most terminals (closest to the face of the transmitter) with the red wire facing toword the sticks.


*************************************If by "red wire facing toward the sticks" you mean red wire facing toward the FRONT of the transmitter then great that is exactly what I have.



The "semi striped" blue/white, red/yellow, orange/black, black plug which exits the rear of the white battery case plugs in directly next to it with no space between the two. The orange/black wire should be closest to the front of the transmitter.

**************************************My next plug is also right up againt the front plug with no gaps but the colours are slightly different. I have: Grey/white,red/yellow,solid black,orang/black but like yours the orange black wire is closest to the front leaving three unused pins at the rearmost part of the board.


This should leave you with three empty terminals at the rear of the board. (Yup it does)I was going to take a picture but misplaced my camera. Hopefully this will get you going.

Steve B
**************************************Thank you so much Steve, now I will be able to use this system in my testbed rocketplane (f impulse). Rocksim sims out the design to about 7000-10000 feet. When I have proven the design I will be building a much lager version (G-J impulse) and installing a Microstar2000 encoder and a 2.4Ghz module in the old Kraft transmitter. The module is supposed to be good to 5 miles (26,400 feet) which should be more than enough.

Thanks again!

Gary.

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Old 07-21-2007, 12:35 AM
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Default RE: Help with my Kraft series seventy nine

Hello Steve,

Thanks again for your help. All went well with the battery replacement. The TX meter shows full power. I have another problem all of a sudden. I replaced the batteries in the receiver as well only to discover that someone had cut the plug of the Rx power pack! This would not be a big problem but for the fact that the wires from the pack are red white and black. And nothing in the wiring harness matches.

There is a connector block on the Rx where the servos plug in. does the battery plug in here or do I plug it into the 3-wire connctor "hanging" off the Rx?

The connector block has 4 servo connections and one connection that is different looking. My thought was that this "different" connection is for the retract servo since it is not on a proportional channel. But it also might be the "hanging" connector that runs the gear servo. Upon examining the receiver board red and black wires from BOTH of these connectors go to exactly the same place. It is only the white and yellow wires that go to separate parts of the circuit.

Your five channel have the same kind of block and hanging wire connections?

Where do you plug in the power?

Thanks again,

Gary.

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Old 07-21-2007, 06:20 PM
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Default RE: Help with my Kraft series seventy nine

The battery connects to the switch harness and then the switch harness plugs into the RX. Got to have a way of turning the thing on and off. The switch harness will also have a third connector for charging without disconnecting any other connections.
This is a TYPICAL switch harness
http://www2.towerhobbies.com/cgi-bin...&I=LXJC15&P=ML
Please note that I am NOT saying this will work with your radio.
Again, try http://www.kraftmidwest.com/ for parts and specific help. They're not too far from my mothers place in Novi. I visited them once a long time ago. Lots of odds and ends laying around back then.
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Old 07-21-2007, 07:41 PM
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Default RE: Help with my Kraft series seventy nine

I have the harness, And have used this radio before. Sombody cut my battery plg off.

The battery pack is red+2.4v,white0v,and black-2.4v

The harness does not have any plug on it with red,black,white.

The reciever DOES have a plug on it with red,white,black coming out of it to the circuit board but the only plug that could possibly connect to it it red,black orange. Orange comes from the charger plug not from the battery.

Here is the weird part, Although the battery has three wires coming out of it the only plug it could have gone to only has red and black! The reciever has red,black, orange going into it and coming out of that plug coded as red, white black.

See my problem? Three wires from the battery pack to a two wire connection into the harness and an orange wire from the charger joins this bundle and into the receiver....The orange wire must be for charging only.

But then why does the pack have three wires in the first place? Could it have been just so this pack could be used with other products?

Does anybody know if these old 72mhz Kraft units use -2.4v, 0v, +2.4v or do they run on just ground and +4.8v?

I know digital and power electronics but next to nothing about radio.

Gary.
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Old 07-21-2007, 09:40 PM
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Default RE: Help with my Kraft series seventy nine

When you measure from black (ground) to red (positive) on the battery you should measure @ 4.8 volts. 3 wire battery packs are fairly common but for most purposes you can simply remove the wire that is NOT red or black. The battery charges with 4.8, it puts out 4.8 and the radio runs on 4.8 volts.
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Old 07-21-2007, 09:49 PM
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Default RE: Help with my Kraft series seventy nine

This company says they have Kraft connectors.
http://www.srbatteries.com/rsaccess.htm

Picture here of a Kraft completely connected and in a thread about the system.
http://www.rcuniverse.com/forum/fb.asp?m=4236657
Note the wiring.
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Old 07-21-2007, 11:23 PM
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Default RE: Help with my Kraft series seventy nine

Thank you Bruce!

Just what I needed to know. I was going a little batty!

Gary.
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Old 07-21-2007, 11:26 PM
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Default RE: Help with my Kraft series seventy nine

Now to install the replacement batteries and start on the servos. Oh by the way Kraft Radios had this great reputation for quality but the soldering on these boards is awful! I am re-soldering every connection.

Gary.
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Old 07-22-2007, 01:21 PM
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Default RE: Help with my Kraft series seventy nine

Kraft was agreat radio in their day. I had a KP7C myself before it was stolen. I think a lot of soldering was done by hand back then and therefore subject to human error. Good soldering is both an art and a skill which requires proper equipment for the task.
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Old 07-22-2007, 02:29 PM
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Default RE: Help with my Kraft series seventy nine

This was NOT done by hand. Hand soldering ALLWAYS comes out better than even todays best solder bath techniques. You have your facts cattywampus!
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Old 07-22-2007, 06:35 PM
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Default RE: Help with my Kraft series seventy nine


ORIGINAL: fly_boy_bc

This was NOT done by hand. Hand soldering ALLWAYS comes out better than even todays best solder bath techniques. You have your facts cattywampus!
Pardon me, but I do soldering (electronics) for a living and have been through several professional soldering schools and have several certificates. I have seen some of the most God awful excuses for soldering performed by so-called expert technicians that I could do better with a cutting torch. A properly set up and operated wave soldering machine will do a fine job on most boards. Whether or not YOUR boards were manually done or wave soldered is hard for me to say fome this distance. I was merely offering a possibility. Me cattywampus? Get a grip buddy.
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Old 02-21-2009, 09:44 AM
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Default RE: Help with my Kraft series seventy nine

Gee! I wish "I had gone through several professional soldering schools". Moronic statement.
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