C-Mark MR2450 manual.

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   Hi,
I am looking for either a manual or a circuit diagram for a C-Mark MR2450 amplifier.

I have one fan that runs slowly all the time and one that doesnt.

are they dual speed fans or on all the time ? Are they on thermostats ?

Is there a replacement fan available to retrofit ? 

Any information greatly appreciated.

Regards
Dan.

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bobthelogs Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 25 April 2017 Status: Offline Points: 8	Post Options Post Reply Quote bobthelogs Report Post Thanks(0) Quote Reply Topic: C-Mark MR2450 manual. Posted: 26 April 2017 at 12:40pm
	Hi, I am looking for either a manual or a circuit diagram for a C-Mark MR2450 amplifier. I have one fan that runs slowly all the time and one that doesnt. are they dual speed fans or on all the time ? Are they on thermostats ? Is there a replacement fan available to retrofit ? Any information greatly appreciated. Regards Dan.

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4946	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(0) Quote Reply Posted: 26 April 2017 at 9:11pm
	yes they're dual speed. There's a n.o. bimetallic thermostat on each heatsink which switches up to fast when they're too hot. They normally run at a slow-ish (still quite fast) speed when you power up. If one isn't running at all I'd suspect the fan itself, they're the cheapest brand known to humanity.
	Kevin North Staffordshire

bobthelogs Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 25 April 2017 Status: Offline Points: 8	Post Options Post Reply Quote bobthelogs Report Post Thanks(0) Quote Reply Posted: 17 May 2017 at 3:39pm
	Hi. Thanks for your reply. I have looked inside and the fan is only 2 wire 24vDC so I suspect they are ok. I have swapped the suspect fan from left hand side to the right and it works. The thermostats on the *working side seem to be n/o , and when I disconnect them the fan stops and I get a red fault led on. Am I correct in thinking they are one speed 24v fans, that when stopped the heat sink overheats and then switches on the fault led as an indication ?? Any information appreciated. Regards Dan

bobthelogs Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 25 April 2017 Status: Offline Points: 8	Post Options Post Reply Quote bobthelogs Report Post Thanks(0) Quote Reply Posted: 17 May 2017 at 3:40pm
	Sorry, that should be n/c. Dan.

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4946	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(0) Quote Reply Posted: 17 May 2017 at 11:24pm
	there are 2 thermostats per channel, one on top and one underneath. One is an overtemp cutout and is N.C. The other is the fan speed control and is N.O. When the heatsink gets past 60 degress C the NO one closes and the fan goes from slow to fast. If the amp continues to heat then the NC opens and puts the channel into protect.
	Kevin North Staffordshire