Stern's New Spike System & Shaker Motor Service Bulletin
- Thread starter mwong168
- Start date
Hmmm... One begs the question, what is different with the aftermarket motor vs the OEM that it requires that external cap? And what do these aftermarket suppliers have to say about this bulletin?
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luch
Super Member
Clearly that is what this bulletin is trying to do, but Stern hasn't changed their shaker motor so what is the purpose of the cap on the aftermarket? There must be a reason the cap was added to the CT version to overcome a difference in the motor they use over the Stern OEM.
I do question Stern's claim that this 100uF cap would stress the shaker power supply section to the point it would cause a PCB failure upstream though. The amount of current the shaker motor itself would draw during operation should be WAY more than the amount of in-rush current that cap would draw on power up, so I'm a little skeptical. Now if the aftermarket motor being used draws more operating current than the OEM, that could cause issues with the drive circuitry...
My 0.02.
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zebulon
Member
The cap is most likely there to act as a "soft -start" conditioner. I can't see that it would harm anything other than it would filter out the majority of the pwm by dumping voltage back into the line in the breaks between pulses. Since capacitors store voltage and not current I have no idea what they are talking about.
A simple fix would be to drive the motor by a mosfet and let the node dive the mosfet, then you'd have minimal current draw from the node. That's basically what every one of my boards does that I sell.
A simple fix would be to drive the motor by a mosfet and let the node dive the mosfet, then you'd have minimal current draw from the node. That's basically what every one of my boards does that I sell.
Yeah, it's all a bit strange if you ask me. Apparently removing the cap from the shaker solves the issue though. Terry has sent out replacement node PCB's to all the customers that bought a shaker and had issues, and once the cap is removed the customers are reporting no problems.
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