Polarizer Servo (Corotor ][ +) Issues

[TvMind]

Hey folks been a while.

Okay so last week I started having issues with above mentioned component i.e. temperamental Vertical. Skew in the Prog menu of my Startrak 400 "kicked" it back to life. There has been a good deal or rain followed by temperature plummeting so I suspect things froze up (they shouldn't really as I had no trouble last year in -37 C , yes you read that right brrrrr). Ok so now no Vertical at all. Rather than jump to conclusions I pulled out the old multimeter and did some tests.

The terminal indicate activity, but something odd or maybe not. (Please indudlge me here I am trying to determine if it's not the receiver - unlikely I know but before I start ripping things apart on the feedhorn and scare the neighbours kids cursing trying to get those blasted screws off the servo - good luck !! - ).

+5 is active during polarity change (5.25 V dc) and then returns to 0.18 V dc.
Pulse: V-Pol = 0.465 V dc (then returns to 0.036 V dc). H-Pol=0.657 V dc and returns to 0.418)
Incidentally Skew Range (0000-255) is approx 500 mV (0.25 - 0.75 V dc)

If I leave the voltmeter connected I sometimes see the voltages go berserk, well not the usula idle voltage.
Now I should have checked these, or recorded them when it was working, but I can't recall or locate technical information either on the inner workings of the servo (had one apart once upon a time and reversed the schematic but that's long gone), or the proper signal/ voltages during operation.

If I have time I will get out there tomorrow and take a look in the throat first of all to clean out any possible debris, nests etc (got cap on of course), and try to unfasten the servo if possible - those are good and tight on there.

Well any electronics engineers out there can tune in, pun intended, and offer up some technical info on this.
Uhm, been trying to locate a Startrak 400 Service Manual, so if anybody knows please chime in as well.

Cheers and may the bugs stay out of your "throats".

 

[wvman]

Hey folks been a while.

Okay so last week I started having issues with above mentioned component i.e. temperamental Vertical. Skew in the Prog menu of my Startrak 400 "kicked" it back to life. There has been a good deal or rain followed by temperature plummeting so I suspect things froze up (they shouldn't really as I had no trouble last year in -37 C , yes you read that right brrrrr). Ok so now no Vertical at all. Rather than jump to conclusions I pulled out the old multimeter and did some tests.

The terminal indicate activity, but something odd or maybe not. (Please indudlge me here I am trying to determine if it's not the receiver - unlikely I know but before I start ripping things apart on the feedhorn and scare the neighbours kids cursing trying to get those blasted screws off the servo - good luck !! - ).

+5 is active during polarity change (5.25 V dc) and then returns to 0.18 V dc.
Pulse: V-Pol = 0.465 V dc (then returns to 0.036 V dc). H-Pol=0.657 V dc and returns to 0.418)
Incidentally Skew Range (0000-255) is approx 500 mV (0.25 - 0.75 V dc)

If I leave the voltmeter connected I sometimes see the voltages go berserk, well not the usula idle voltage.
Now I should have checked these, or recorded them when it was working, but I can't recall or locate technical information either on the inner workings of the servo (had one apart once upon a time and reversed the schematic but that's long gone), or the proper signal/ voltages during operation.

If I have time I will get out there tomorrow and take a look in the throat first of all to clean out any possible debris, nests etc (got cap on of course), and try to unfasten the servo if possible - those are good and tight on there.

Well any electronics engineers out there can tune in, pun intended, and offer up some technical info on this.
Uhm, been trying to locate a Startrak 400 Service Manual, so if anybody knows please chime in as well.

Cheers and may the bugs stay out of your "throats".

Try this link. I think it may be helpful. 400 satellite receiver | manualzz.com Old manuals are getting hard to locate. Here's another link you may find useful at some point in time. Receivers Master Password - Ra2D

If you have another servo or have the old one off, hook it up at the receiver and see if it works there. Much easier to test it and know it's working and then go from there. I have some old C-Band receivers that use a servo, but I only used them to move the dish until I had some time to plant some extra poles and set up multiple dishes with Titanium LNBF's.

When you pull the servo, check to make sure that the probe moves easily. I've seen corrosion in there that stopped the probe from turning freely. Poor connections, water inside a cable or bad cable can cause similar problems.