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Meade 560 drive corrector

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#1 DavidHickey

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Posted 20 November 2012 - 09:42 AM

Hi,

I've had a 16" Meade Starfinder reflector since the early 90s that has a #560 drive corrector and a #36 hand controller. The drive corrector appears to have died. When it is powered on, the RA and Dec motors do not move when controlled by the hand controller, and after a few minutes of being on there is a burning smell coming from the 560. I opened it up and saw the black burn mark on the circuit card under one of the parts. I found another #560 corrector online and tried that, but it doesn't work either (stopped it before the part heated up to the point where it burned the board though). I've replaced the power supply with a new one from Condor which didn't help either. The last suspect is the #36 hand controller, maybe something is shorted in their. I haven't been able to find one online though to test that theory. The actual RA motor appears to be fine - when I plug that in directly to an outlet the motor does move.

I called Meade the other day and they said they no longer support these components or even have schematics they could send. Has anyone experienced a similar problem with the Meade 560/36 setup? Is there an aftermarket drive corrector that could be used in place of this if replacing or fixing the 560/36 turns out to not be possible?

Thanks,
Dave

#2 Geo.

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Posted 20 November 2012 - 11:30 AM

Only time I've seen these fail is due to the TIP30s over heating. Over heating is due to the TIPs being asked to deliver too many amps, usually as a result of something that has significantly increaded the mechanical load. The one I repaired had a faulty RA clutch that was binding the RA axle.

I have some parts if you want to send the 560s and hand control to me I can check them out. But I doubt that the HC is your problem. If it was in your shoes I'd build this controller.

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#3 Geo.

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Posted 20 November 2012 - 11:33 AM

Here's the hand controll layout:

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#4 DavidHickey

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Posted 20 November 2012 - 01:53 PM

George,

Thanks for the response. The burn mark was under one of the TIP30 chips on the original 560 controller. The datasheet shows it is good up to 150C, I measured 50C before I shut it off after I had it opened. Obviously it got hotter than that when it originally burned the board but I have no idea how hot or if the chip is truly fried. I know the chips and board inside the second 560 box I have looks ok visually, at least. I'll take a look at the RA motor and gearing and see if there is something awry in there.

Thanks!
Dave






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