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Crown XTI 2000 Motherboard


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#1 ixchenoxi

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Posted 09 March 2012 - 05:36 PM

Hello,

I own 3 crown xti 2000's i've recently bought used and im starting to regret it.

I've had to replace the LCD Display motherboard in all three of the ampifiers(which was not covered under thier factory recall) and while i was doing that, i noticed a unique problem on the motherboard with a component called RT3.

It appears the piece is heating up and breaking down. First Two Photos are from an ampifier i dont notice the problem on, second set of photos is from the ampifier im concerned about.

Any advice would be greatly appreciated.









#2 joust

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Posted 12 March 2012 - 10:42 AM

RT3 is a PTC (Positive Temperature Coefficient) resistor. The mean resistor value is quite low when cold and goes up quickly when heated up (current passes through). RT3 is used in the crowbar circuitry of the main rails circuit. If a fault is detected, the crowbar is enabled and the rails voltages are shorted out.
The third amp had a bad 'trip' and the PTC faulted. THough, it did do its job! smile.gif Return the amp to a Crown service center for repair.

joust

#3 ixchenoxi

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Posted 12 March 2012 - 05:08 PM

Joust, thanks for your response. At the request of the field service tech, im uploading some more photos of the xti 2000.

Thanks,

-Mike













#4 joust

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Posted 15 May 2012 - 01:25 PM

I've had instances where only the PTC faulted. Though, the crowbar circuit (SCR, et al.) may be at fault this time.