Titanium ASC1 or ASC-1: Read This Before Buying

[el bandido]

You don't need a fan or anything else except a small dc supply. Nothing inside the asc1 will be working except the counter. Of course, the Asc1 has to be powered ON. But the energy to move the dish comes from your portable supply.

[ArloG]

I have 3 ASC-1 controllers 'in the queue' on my bench. 2 with dead MCU's and one displaying LNB is shorted !
The first 2 will definitely need controllers replaced and then programmed.

I would say that depending on the motor itself. The limit switches and diodes would be a great place to check.
The H bridge relays in the ASC-1 don't particularly make a defined 'click'.
But if you suspect that one may be faulty a sure fire test would be to put 2 #194 automotive bulbs in series and then make a pigtail to put across the motor terminals along with the motor.
Motor unloaded. Either direction. The bulbs should be close to equally bright. If they dim substantially in one direction but not the other. Or flicker slightly more dim. Maybe relay contacts. Maybe.

Either direction the dish is directed. The bulbs should light up but not be very bright. Because you're dividing the amp draw between the motor and bulbs.
I've pulled the relays here and the NO/NC contacts easily pass 5 amps with very little voltage drop at 24 volts. Those were several years old.
After a billion "bumps" W-E tweaking sat. positions.

IF the bulbs dim substantially anytime the motor is powered either direction. 2 reasons. The relay contacts could be in fact faulty. Or the motor could be shorting.
If the lamps suddenly get brighter and then you get an error on the display. It's the motor.
Bad brushes. Tarnished microswitches in the motor limit circuitry.

I've seen limit switch diodes short and seen them open.
Open diode, the motor keeps on truckin' in one direction but won't reverse after a switch is tripped by the limit cam.
And the same if one shorts. Except then the motor keeps going after that limit switch is opened by the cam for that direction of travel.

The reed switch in the motor gets ~5vdc from the optocoupler circuit in the controller. The reed switch has to be able to pass current. Not much. To turn the LED on and off in the opto.
Certainly a good test at the dish would be to put multimeter across the sensor terminals and loosen the magnet to trip the switch. It must traverse from that 5-ish volts (switch opened, no magnet close) to very close if not 0 volts when the magnet closes the switch.
But that's not a real test for the switch integrity. Old contacts can provide a 'dirty' signal at the opto. Missing pulses, create extra ones.

The transformer runs very warm. Probably a bit more when the actuator is on a long run pushing the dish. But the #194 bulb test will show any problems.
One secondary winding powers the ASC-1 circuitry and the other is for the motor power circuit.

As EB suggests in #39. I would simply unbolt the motor after moving the dish to the reference position. So you can set it all back up with limit switches aligned for it.
Put the ASC-1 on a table and wire the motor up directly close to it.
Hook up the bulbs to the motor terminals and run it. Give it a good voltage check. Stick a big honkin' screwdriver or a tool in the coupler and drag it down while its running.
Tap the limit switches firmly and wiggle the plungers. Give the motor housing a few raps. Or better yet just pop it open and check the brushes, springs, commutator. Loose magnets.
Everything to troubleshoot up to the controller can be done w/o opening it up or randomly swapping relays.

[el bandido]

Maybe my suggestion was not clear. All you want to do is see if the actuator counts pulses in both directions. Nothing more than that.

Simple steps:
(1) Disconnect the motor leads to the actuator from the back of the Asc1. Leave everything else connected. Verify the Asc1 ON.

(2) Briefly Connect the actuator motor power leads to a dc voltage source and watch the front of the ASC1. The positioner counts on the front of the Asc1 should change immediately when dc voltage is applied to the actuator motor.
(3) Reverse the actuator motor power leads and test again. The positioner counts on the front of the Asc1 should change immediately when dc voltage is applied to the actuator motor.
<End of Test>

In a properly working system, actuator pulse counts go up or down, depending on the direction of dish travel. This test will cause the pulse counts to be added to one direction. The positioner pulse counts do not know polarity of the actuator motor, so they will be counted in one direction only which means the dish tracking will be off. Disconnecting the motor or doing anything else will not change this.


If you were real careful and did several additional steps, you might not upset the dish tracking pulse counts. Most likely though, the dish is already out of sync with the pulse counts as usually that is the case when there is a positioner problem.

[ArloG]

EB. Unless you have special firmware. The counter will not increment unless the H bridge is active.
In no instance have I even been able to increment the counter with just the encoder and motor not energized.. If so, I would have been a happy camper.
Voltage will be present at the sensor terminals. But operating the encoder alone will not change the counter.

I had discussed this with you in the past pertaining to motor coast after the controller de energized it. Those little added gear train movements after the counter is stopped (but armature slows to a stop) add up and create count errors.
Bottom line. Motor is turned off by the ASC-1, the counter is immediately stopped. No matter if you move the encoder manually or power the motor externally.
As an addition. When searching for and peaking satellite positions before storing them. Positional errors for all other satellites that needed global tweaking before adding the brake reduced by a great amount.
This would occur every time the dish was 'bumped' a few counts at a time. Example. Not being able to lock a signal, but you know the satellite must be there from interpolation.
So you move it a little and perform a blindscan to see is a transponder was snagged. No? Move it a bit more and do it again. Until you finally do hook that fish. Then tweak it in.
Wondering if a V box does it differently.

FYI. When I added a dynamic brake inside of the motor housing in the form of a DPDT relay with the NC contacts connected in series with a .22 ohm braking resistor to the brush wires.
Errors from coast immediately decreased by a great amount.
This was to be a provision in the prototype ASC-1 as was the aforementioned (Brian) PWM mosfet in the motor circuit to coast up/down the motor. Which would have been damned nice to keep.

[el bandido]

My apologies if my information is not correct!
I should withdraw from the conversation of fixing the Asc1 as it is not something I normally use. I am certain lme will find a solution!

[ArloG]

And my apologies too. Good intentions, I know. Hope you accept the same.
I'm just a bit peed that the tech. on these is 'eyes only' still even after they were discontinued. Glad Brian is still supporting keeping them working.
They do have similarities with the V box movers. And is why it would be interesting to know if the counter did actually keep active after the motor is shut down.
Kind of seems not though because the counter wouldn't know which way to go since the encoder is pulse/switch closure only. Not a quadrature encoder like your ham rig would have for he VFO.
But. Try to trust me a little. Because my nose has been in deep with the ASC-1 to R.E. it. As far as the circuit and perpheral components go.
A few I've seen here that I worked on have solder pads lifted just because they felt like it.
And there's a bit of dodgy solder work where the various after mfg. mods such as 22 kHz pass-thru and such was done.
Just that I wouldn't jump to swapping relays w/o proper soldering equipment and practices go. Some of the pc board traces aren't very rework friendly.

The motor could be spun all the live long day in one direction on it's own power and counter not change one bit.
Until the E-W or receiver commands it to actuate. When the direction button is released the counter simply stops and the relays open.
In the case of a go-to command from a receiver. The controller doesn't know which direction the motor is running. Just that the encoder is providing pulses.
Break the sensor connection or stop the magnet and an error will show.
I do believe that there is an over current detection circuit though. Because I've seen 'motor stall' here and there. Different from a limit switch notification / error.

Again. My apologies.

[lme]

Going back to my post #35, what is the purpose of the single transformer, and where is to be installed if needed ?

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Thx.

[ArloG]

I may be wrong but perhaps to replace one of the dual secondary windings of the existing transformer. Wired into the board power connector for the motor only circuit.
The secondary windings are specd. at 22 & 24 VAC. One to power the electronics, one to run the motor.
Most actuator motors are rated at 36 VDC. After the rectifier circuit in the ASC-1 the voltage will be a bit above 24 VDC. But once it reaches the dish. Depending on the cable used and length.
Voltage drop could be considerate. As well as current drop. The motor might exhibit even lower voltage when it is running if measured across the screw terminals in the motor housing.

I personally like the idea of the switch mode supply for the motor circuit if only because they allow a small margin of voltage adjustment and regulate current very well. Something that a transformer can't do.

[lme]

Sounds like the East relay is going bad.

Eliminate the relays and see if the actuator moves correctly.
To test, remove the two power leads for the actuator from the back of the Asc1. Find some type of small 12-36 volt DC power source, and connect the actuator leads to the power source while watching the front of the Asc1. The counts on the ASC1 should change when power is supplied to the actuator. Then reverse the the actuator power leads, and test the opposite direction. Again the counts for the actuator should move on the front of the ASC1 is supplied.

Portable drill batteries and even a wallwart type dc supply can be used for this test. Move the dish close to the center of the satellite arc if possible for this test as that is the area that takes the least amount of energy to move.

I did the test today, and the counts on the display didn't change.

[ArloG]

Unless the ASC-1 is commanded to move the dish. Aka: apply relay coil voltage on the h-bridge.
You can put your own power on the motor and the counter won't increment/decrement at all.
And. Again. You can spin the encoder magnet by hand all-the-live-longed-day if the unit is not commanded to actuate the relays.The counter will not move a single digit.
Motor/relays off. Counter deactivated. It's in the firmware.
Maybe a vbox works differently. But not this critter.