DG-280 rotor doesn’t turn predictability

[Rob Ram]

Hi,

I recently installed the Sadoun Power Tech’s DG-280 HH motor and cannot get it to turn predictability. I am using Technisat’s SkyStar 2 (SS2) PCI board with Technisat’s latest drivers (4.4.1) and a positioner console by MiBi; found in SS2DiSEqC110.zip.
Even though the SS2 card is only specified for DisEqC 1.0, it will generate DisEqc 1.2 commands to the motor. It is limited though, to 350 ma maximum; but, should work with the DG-280. Other users have claimed that the SS2 board does work with the Moteck SG-2100.

Test set up:

• I have a Channel Master coaxial power injector connected to the SS2 RF port to monitor the DisEqc commands. The device is a simple device using a choke to isolate the power from the RF. An oscilloscope is connected to the power end of the choke.
• A PC sound card scope is connected to the oscilloscope line output port and is used to capture single shot events. While not nearly as accurate, it does provide a useful capture capability, which otherwise is lacking on the “real scope”.

Some test results:

• Using an oscilloscope, I can verify that the correct DisEqc 1.2 code is being delivered to the SS2 RF “F” connector, but under no load conditions (no connection to the motor).
• The east west buttons on the DG-280 does work as expected.
• I have 50 feet of RG6 cable between the PC and motor, direct connection.
• The DG-280 will return to 0.0 (south) using the GoTo 0.0 command, but not consistently. Most of the time, a Goto 0 command is ignored.
• Goto –17.1, as an example, the motor did turn to its limit. It actually kissed the roof; but no damage done.
• With the motor connected, after the “E0” “Framing byte function”(Command from Master, No reply required, First transmission), the oscilloscope shows a positive spike (very short duration about 2 volts) at the SS2 end. The spike occurs just after the odd parity bit is sent. Possibly this spike is interrupting the command. When the DG-280 disconnected, the spike does not happen. There are other spikes that appear elsewhere in the command string, but not as repeatable as the “E0” spike.
• The SS2 generates a square wave 1 volt peak to peak at 22Khz for DisEqc commands; as measured with a good quality oscilloscope. The SS2 also generates the 12 and 18 voltages accurately, as measured with a digital volt meter.
• I do not have a normal FTA receiver. I wish I did to simplify the setup; but my wife will kill me if I buy any more satellite stuff

Several questions:

• Has anyone been able to drive the DG-280 motor with Technisat’s SkyStar 2 PCI card?
• Is there a schematic available for the DG-280. A direct connection to power the motor, rather then coaxial power, will ovoid power glitches; as may be the case in 6 above. This will be a big help if available.
• Any one know of a manufacture that makes a bi-directional line buffer for DisEqc 1.2 commands?

Any help will be greatly appreciated.

[jcdenton12]

Are you still having the same problem?

I have SS2 and DG280 HH mount and had same problem until yesterday evening

then I found a solution and it works great now


If you haven´t solved it yet, tell me and I´ll try to help you

[Muad'Dib]

Use DVBViewer or AlDVB!!!

[Rob Ram]

Are you still having the same problem?

I have SS2 and DG280 HH mount and had same problem until yesterday evening

then I found a solution and it works great now


If you haven´t solved it yet, tell me and I´ll try to help you

Thanks jcdenton12 for the reply. Yes I still have the problem, any help will be appreciated. Also I did purchase a Mercury II FTA receiver, mainly for setup use. It does work better then the PCI card, but still have problems getting the DG-280 to turn. Many times the receiver indicates that the motor is turning but a visual check on the dish position proves otherwise.

I a day or so (weather dependent), I plan to bring the DG-280 down off the roof and rip it open to modify the circuit board. The modification will power both the circuit board and motor from an external power supply. The receiver Diseqc commands will control the motor as before. At the least, this will prevent potential damage to the Technisat Sky Star 2 PCI card.

To "Muad'Dib". I am using DvbViewer Pro Version 3.9.2.0. I suspect once I get the DG-280 running ok, the PC positioner will also work ok.

[Muad'Dib]

Just try with Altdvb or DVBDream too, it cannot hurt.

[plastik]

I am having exactly the same problem with my HH, but with a Dreambox receiver (dm600pvr). Sometimes my motor ignores my commands (most of the time). I took the motor in and attached it to a very short cable (1m) for testing. The result was the same.
I wonder what is the solution mentioned by jcdenton12 a few posts before.

[Muad'Dib]

RESET your motor.

[bali]

RESET your motor.

please tell me how to reset my DG-280

i am having some problems too


thanks

[Muad'Dib]

There is no reset button on the motor itself??

[Rob Ram]

I am having exactly the same problem with my HH, but with a Dreambox receiver (dm600pvr). Sometimes my motor ignores my commands (most of the time). I took the motor in and attached it to a very short cable (1m) for testing. The result was the same.
I wonder what is the solution mentioned by jcdenton12 a few posts before.

The solution mentioned was in reference to the computer power supply. You may want to check your computer power supply. Measure the voltages and verify that they are in spec. An overloaded PC power supply can create problems. Also if you have an oscilloscope, look at the noise on the various voltage output sources. However, this was not the problem in my case.
I haven't finished Spice circuit simulation of the internal CPU board, but the problem seems to be a design problem when the DisEqc 1.2 motor positioner control signal is slightly low in amplitude. I did successfully modify the DG280 to be powered from an external power supply, however the Technisat SkyStar PCI card still could not control the DG280, yet it does correctly control DisEqc type switches. By contrast the motor operated correctly when controlled from a Mercury II receiver with the external power supply modification. The main difference between the Mercury II and the Technisat SkyStar PCI card is a slight difference in the DisEqc 1.2 control signal amplitude, where the Mercury II is the greater amplitude.