AD3000IP - broken pulse sensor?

D

drbob

Member
Hello,

Has anyone here heard of the pulse detection breaking on an Echostar AD3000ip? That's all I'm left with as a possibility after the following tests:

Continuity on both motor and pulse pairs: good

Reed sensor removed and tested with magnet: good.

Connect LED to pulse lines and engage motor: LED flashes as expected.

Connect wires to AD3000IP and try to move dish: motor error!

I'm at my wits end. The receiver appears to work 100% fine in every other respect. Dish is currently pointed at 13º E and can see all FTA analogue and digtal channels. It was bought second hand as fully working a week ago. I don't want to try to return it until I'm sure it's not me doing something wrong.

Any suggestions as to how to proceed would be much appreciated.
 
Not sure what you mean by the LED flashing on the pulse line. You'll only get a train of pulses when the motor is in operation and moving the dish.

Is this a replacement for a previously operational receiver and dish setup?
 
drbob said:
Connect LED to pulse lines and engage motor: LED flashes as expected.
Click to expand...
Llew said:
Not sure what you mean by the LED flashing on the pulse line. You'll only get a train of pulses when the motor is in operation and moving the dish.
Click to expand...

I mean that if I run power to the dish actuator motor, with an LED connected to the pulse lines (I use my continuity test box and the receiver for this), the dish moves and the LED flashes apparently confirming the presence of pulses on the line. However when I connect everything back up to the receiver and try to move the dish, I still get "motor error". Could the fact that the continuity tester provides it's own 20mA current on the pulse lines be affecting things?
Llew said:
Is this a replacement for a previously operational receiver and dish setup?
Click to expand...

Our system has been out of action since our old receiver (a technomate TM5500DAPCI) died a couple of years ago with a bad power supply. Before buying the AD3000IP I discovered that our installers had used cat5 data cable for the motor and pulse lines. That cable failed a continuity test, so I replaced it with a 4 core, 6A rated cable. Unfortunately the cowboys who put the cat5 in are the only local installers who will deal with motorised systems so I'm having to try and fix it myself.

I'll try to post a you tube video to show the symptoms.
 
Have you tried resetting the Echostar to factory default and going through the process of defining your dish limits? That's what you need to do first , as the previous owner will have different limits, satellites setup etc.
 
Llew said:
Have you tried resetting the Echostar to factory default and going through the process of defining your dish limits?
Click to expand...
I did, but that was before I removed, tested and replaced the reed sensor. On the off chance that my messing with it unstuck the sensor I'll try another reset. The interface of the echostar appears to allow the changing of dish limits after inital setup. I'm seeing "motor error" on the install screen where you change the dish limits.
 
I reset the receiver but that made no difference, still get motor error when trying to move the dish.

Here's a youtube video showing the symptoms - the dish does move, but the receiver can't detect the movement.

[TUBE]VvD4cNLQNhc[/TUBE]
 
A possible cause might be that the suppressor diode D16 has broken down, misshaping the incoming pulses. It's there to stop transient or any peak voltages on the line giving a miscount.

An oscilloscope reading would confirm that you have the correct pulse shape and voltage going to the counter; other than that you could try removing the diode whilst you do your checking, to discount the possibility of the diode being responsible.
 
hi --drbob --
i have a spare 3000 ip and actuator in my workshop i can simulate your error by disconnecting either of the pulse wires at the reciever end --
regards nelson .b
 
Llew said:
A possible cause might be that the suppressor diode D16 has broken down
Click to expand...
Is that diode clearly marked on the circuit board? I'm not very adept at soldering/electronics (most I've ever done was replace bad capacitors on a computer motherboard, it worked afterwards though). I'm willing to try, would I need to remove the diode completely or just bridge round it? Unfortunately I don't have access to an oscilloscope to check whether the signals from the reed switch are the correct shape.

nelson_b said:
i have a spare 3000 ip and actuator in my workshop i can simulate your error by disconnecting either of the pulse wires at the reciever end --
Click to expand...
Thanks for that :). I've checked and rechecked the connection of the pulse wires and they are good. As I said earlier there is a pulse being transmitted. My camera isn't really able to pick up the led on my continuity tester flickering (there are at least 10 pulses/second) but here is a video of the pulse wires connected to the tester whilst I move the dish.

[TUBE]U2CC-RBy14c[/TUBE]
 
Before you dive into the receiver, if the dish isn't too difficult to get to, why not run two temporary wires up for your pulse to eliminate the cabling totally regardless of your tests so far. If you've changed the reed sensor and cable then the receiver must be at fault and you can return it :)
 
satelliteman said:
why not run two temporary wires up for your pulse to eliminate the cabling totally regardless of your tests so far.
Click to expand...
That would be quite tricky as the dish is on a pedestal 60m away at the far end of my garden...
satelliteman said:
If you've changed the reed sensor and cable then the receiver must be at fault and you can return it :)
Click to expand...
I may well try that but it was a private sale from a gumtree advert. I don't hold out much hope that the seller will do the right thing.
 
drbob said:
That would be quite tricky as the dish is on a pedestal 60m away at the far end of my garden...
Click to expand...

Ok, see your point, that's some distance there.

Could do with a spare 36v receiver here to try or a Vbox.
 
Try the motor right next to the receiver for starters, as this will determine the cable as being lossy, or unsatisfactory for shielding.

Next, absolutely check the incoming connections for a loss in contact (actually try this first). A few times on these receivers, the spring contact really hasn't clamped down enough on the cable, especially if it is single strand stuff.

Lastly, swop over the cables and relocate the reed switch in the motor, sometimes the pulsing is only a nice square wave when the wheel magnet is not edge on, for some reason
 
I suppose I could bring the motor to the receiver but I'm loath to do that since at least the dish is currently pointed at a satellite. If I remove the actuator I may not fix things and be left unable to receive any channels.

Taking the receiver to the dish is not practical, there is no power near the dish and most likely it would get rained on.

Could fitting a resistor to the motor line help? That would slow the motor down, maybe helping the receiver to see the pulses? I'd need guidance on what resistor I need though. The receiver outputs 5.5 amps, so AIUI there is approx 5V drop for each extra ohm of resistance?

Watts are volts*amps so 36V at 5.5 amps is about 200W of power, does that mean I would need a 200W resistor? I should have paid more attention in physics class...
 
I suppose you could try running the motor at a lower speed, no guarantees that it will allow the receiver to interpret the pulses any better than at normal speed.

Ignoring the temporary increase of motor start-up current, to run the motor at, say 12V, you need to drop 24V through the resistor.

Assuming the actuator takes about 1A after initial starting (usually lower than this with most actuators) -

R=V/I =24/1 =24 ohms

Resistor Wattage = VxI = 24W.

That's the theory, though I don't know if it whether it'll help with your problem.
 
I don't know if it will work either but resistors are cheap so I thought it may be worth a try before attempting more invasive potential fixes.
 
drbob said:
resistors are cheap so I thought it may be worth a try
Click to expand...

Well that didn't work. Same symptoms, just slower dish movement. So I opened up the receiver (breaking the long expired warranty sticker) and diode D16 appears to be the culprit. It has a crack running right through the centre or the part! (See photo below)

I believe this P6KE6.8A diode is the correct replacement part?
_http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6388687

Looking at the degree of discolouration around resistor R3, I guess I should also think about fitting a fan as suggested in other theads about this unit.

Llew, and everyone else who posted suggestions, thank you very much for you help.
 

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Nice result. Might be worth checking for dry joints around the wirewound resister also.
 
Yes, that was the one I suggested checking. Probably took a surge (lightning maybe, although that would have taken out your LNB too :eek:
 
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