GBox dish mover Voltage ?

[Long Hair]

What voltage should my pulse sensor be outputting? It was
around 5volts earlier. But now it reads 20volts,this is not good
I think? The other day it started acting up,moved to -3000 when
it should have been @ 0. and my limit was/is -220. Any info wood
help.

 

[FaT Air]

All the old analog stuff and my gbox, or is it a vbox, don't know, havent seen it in over a year, as it's remotely controlled, are around 5 volts.

 

[Long Hair]

anyone know what I should be looking for inside the box to
fix the high voltage on the pulse terminal. I don't see any burn
marks? Also the button on the front to drive the motor east doesn't
work,but will still click with the remote.

 

[FaT Air]

I'd be looking for a bad reg. or a shunt diode across the reg. it probably supplies 5v to some digital IC's also, then, if either shorted, it likely toasted the IC's. Pretty common 5v reg is the 7805 series.

 

[Long Hair]

Checked the 7805 16v in and 4.9 out.

 

[FaT Air]

MMMMmmmmm, (scratching head)
Without a schematic, just have to figure out where the 20 volts is coming from, then how it's getting to the sensor terminals, MMMMmmmm. I would check all diodes first, might have to remove one lead from ckt. Might be a transient suppression diode shorted somewhere.

 

[Long Hair]

I checked the diodes, and need info. 2 read .480 anode to cathode and .503 cathode to anode. the other go to high resistance (1.) on meter. the two diodes are D10 and D11. Right buy the Coils. Maybe the problem?

 

[Long Hair]

Diodes read right out of ckt. so now what?
the only thing left in the path is a resistor and a sharp [SIZE=-1]Photocoupler.
what is a Photocoupler?
[/SIZE]

 

[FaT Air]

so now what?

just have to figure out where the 20 volts is coming from, then how it's getting to the sensor terminals.

what is a Photocoupler?

A photocoupler is a LED and a phototransistor in a package. The LED turns on the transistor.
I know trouble shooting anything without a schematic is a pain. Patience and perseverance is about all one can do.

 

[Long Hair]

here is a data sheet of the ic hxxp://www.datasheetcatalog.org/datasheet/Sharp/mXtwxrt.pdf