Combines dial a matic box

[JoJoMac]

Dave, Dial A Matic was not available on 7700 combines-at least not from the factory. I have seen some conversions on 7720's, not saying your combine doesn't have it, but....if you have a newer head with a Dial A Matic printed circuit board, and an older combine with the old style auto header control, (it has a switch with only an auto or manual setting, not three posistions like D-A-M) you will burn up the pc board on the header pretty quick. Those little foil strips can't take the voltage the old system puts out. I know that there are adapter harnesses floating about out there, but that won't solve this problem. Joe

 

[JHEnt]

My niehbor had dial-a-matic on his 79 4400. He had the newer potentiometer type switch equipted 216 header and the full DAM contol system. The dial with 3 positions was mounted close to the throttle lever. The circuit box mounts next to the electric valve under the cab step and it uses the round multi pin connector at the feederhouse. I have also seen a few late model 6600 and 7700 in the salvage yard with the same header controls. I would say you still have a shorted harness in the system causing the circuit board failure. I assume you mean the DAM control modual is berning up. If so thats an expensive item to be replacing.

 

[JoJoMac]

let me be a little more specific. D-A-M(Dial A Matic)was available only as a field installed unit on 3300 through 7700 combines . It was not available as a factory option until later models. If a head equipped with a D-A-M sensor is used with a combine with the old style auto-manual switch, the header sensor will fail. The D-A-M sensor on the header is not a potentiometer. It is a printed circuit board with contact strips and a wiper arm. This board is housed in a "box". An adapter harness can be made to make a D-A-M head sensor work on the old system, but the sensor will fail after a short time. Actually, this is a common cause for faiure. These strips cannot withstand the amount of current that goes through the old style auto header control. Yes, there is another "box" in the D-A-M circuit.(It controls the amount of current going to the sensor, among other things) Failure in this component-the amplifier module-is rare but yes, most likely caused by a rodent-damaged harness. Another likely cause is a coil on the contol valve with a short to ground, drawing too much current through the module. Joe

 

[Dave_Grubb]

Turned out to be rodent damage on the wire harness again.

 

[weeyahkah]

As JoJo said,the amperage is too hight for this box but you can use this box to send a signal at a Bosch relay.You had to be abble to make a little bit of electrical circuit.A Bosch relay can support near 20 or 30 ampere depand of the model you use. Bonne chance Weeyahkah