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  #16  
Old 08-15-2007, 01:59 PM
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old_tv_nut old_tv_nut is offline
See yourself on Color TV!
 
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Location: Rancho Sahuarita
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details here:

http://www.bretl.com/mechtvprogress2...vprogress2.htm
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  #17  
Old 08-16-2007, 09:28 PM
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cbenham cbenham is offline
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[QUOTE=mbates14;1289849]

"the hardest part of the whole project was the motor control servo."

Very good color. I hadn't been able to look at any of the picrtures you sent me because I can't get an .rar files program to work on my PC.

The servo for my set has to be the hardest thing I've ever built too.

Congratulations!
Cliff
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  #18  
Old 08-21-2007, 12:12 PM
mbates14 mbates14 is offline
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the only issue i have is when i first turn it on, the loop oscillates from the disc inertia until it stabilizes. it zooms off to full speed, then drops back down to below normal speed, then speeds up past normal speed then eventually locks in. almost like a "ring" effect of the rising edge of a square pulse.

as the battery discharges, itll jump a color frame or two, and it has to lock back in. only takes sec. dont have a 12V 7amp power supply to run the motor. LOL.
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  #19  
Old 08-21-2007, 01:54 PM
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Does it also oscillate in phase if you disturb it slightly? It is possible to have the wrong or right loop gain for either speed or phase or both depending on how your algorithm works. In the circuit for the mechanical TV, a 4044 "type II" phase/frequency detector is used. While the type II 4044 phase detector is very linear for phase, it is nearly "bang-bang" for frequency, resulting in an oscillation when the speed is first pulling in, but then becoming very stable for small phase perturbations.
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  #20  
Old 08-21-2007, 05:20 PM
mbates14 mbates14 is offline
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it sorta bounces back and forth until the disk inertia balances out. once it does, its good to go.
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