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Samson servo 200

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Samson servo 200

Postby discjockeyr » Thu Mar 05, 2020 8:01 am

Hi guys,
I have the samson servo 200 amp and seems that something going wrong. When i power on the amp only the power button led is on and nothing else. The vu meters not responding to signal and no sound from output. I am not remember if when power on the relay should clicking or not. Is there any common fault on this model. I am an electronics engineer so i can check the amp but i am not so familiar with amps.
Thanks
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Re: Samson servo 200

Postby shufflebeat » Thu Mar 05, 2020 11:01 am

Both my Samson amps got retired when the output relays went. Still in a corner awaiting attention.
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Re: Samson servo 200

Postby discjockeyr » Thu Mar 05, 2020 11:38 am

Is just a relay issue?
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Re: Samson servo 200

Postby Hugh Robjohns » Thu Mar 05, 2020 11:43 am

Impossible to say without examining the unit... but failed relays is a very well-known problem with Samson amps.
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Re: Samson servo 200

Postby discjockeyr » Thu Mar 05, 2020 11:58 am

When you power on the amplifier the relay must click correct?
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Re: Samson servo 200

Postby Hugh Robjohns » Thu Mar 05, 2020 12:01 pm

I believe so, yes...

As the manual says (page 7): http://www.samsontech.com/site_media/legacy_docs/Servo23600_ownman_v1_1.pdf

Samson wrote:Initial power-up: For approximately five seconds after initial power-up, the protection circuitry is activated and the speaker outputs are muted. If everything is operating normally, you will hear an audible click at the conclusion of this brief period, as the protection circuitry is deactivated and the Servo Series begins delivering signal to connected speakers (at which point you’ll hear a click). It is normal for the Protection LED to fade gradually after the amplifier is powered off.
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Re: Samson servo 200

Postby discjockeyr » Thu Mar 05, 2020 12:27 pm

Ok thanks, i will test the relay if is supplied with voltage firstly and then if the problem is caused by the relay itselfs.
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Re: Samson servo 200

Postby discjockeyr » Fri Mar 06, 2020 8:54 am

Ok, i found that the relay is dead. I have one that is 8A instead of 10 do you thing that it will be a problem? Usually are overrated.
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Re: Samson servo 200

Postby Folderol » Fri Mar 06, 2020 9:11 am

Provided the coil voltage is the same and it's reasonably compatible size wise you'll probably be OK, but do watch out for coil resistance. If it's too low it could damage the driving circuit.
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Re: Samson servo 200

Postby discjockeyr » Fri Mar 06, 2020 9:20 am

Ok thanks i will try to find the specs of the original one to see the coil resistance. The resistor before the ray way also damaged. Instead of 100ohms it measures 750ohms.
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Re: Samson servo 200

Postby Wonks » Fri Mar 06, 2020 10:00 am

If it's a DC coil voltage, can you tell if the circuit provides a snubbing diode across the coil to kill the back-EMF spike? If not, it's well worth trying to retrofit some.

At 100Wpc into 4 ohms, or 200W (bridged) into 8 ohms, your very peak current will be just over 7A, though that is at full clean power. If you are pushing the amp hard, then you may be getting a bit more power from it and some distortion. So while an 8A relay should cope, I'd prefer to use a 10A relay myself.
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Re: Samson servo 200

Postby discjockeyr » Fri Mar 06, 2020 10:05 am

Yes there is a diode across coil. The amp is used in shop with small ceiling speakers and is never used more than half gain so i assume 8A is more than enough. I was looking in local market and found only 8A that is why i am going to use this one. I have to repair it soonest possible so i do not have the option to wait for an online order from other country.
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Re: Samson servo 200

Postby Wonks » Fri Mar 06, 2020 10:36 am

That should be fine then.
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