Technics SU V505 problems

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hi there

i have a small problem with this amplifier... to be exact with relay that does muting/output selection.. it works fine when i put a bit pressure on it... on power on it usually clicks several times instead of just once :confused:

i tried to look in service manual but under part name says only SSY-107
google also doesn't find anything useful

so i'm asking if anyone knows the substitution for this relay ?

An externally hosted image should be here but it was not working when we last tested it.


thanks for your reply
 
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Are you 100% sure it is the relay at fault and not the drive to the relay that is responding to the pressure... in other words a poor joint in the amp somewhere and the relay is doing its job of protecting the speakers.

You need to measure the voltage across the relay coil to be sure it is present and the relay NOT engaging.

If the relay is faulty then there should be suitable replacements available. They usually follow a standard pinout. Coil voltage and its resistance would have to be matched and the rating of the contacts at least as high as the original.
 
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From what you say that does point to the relay. If the voltage is present across the relay coil then it should work.

As to a replacement. You will have to determine if it is a standard pin out by comparing against other relays in the catalogues. It might help to see a picture of the underneath of it. If a pin compatible one can't be found then it's a simple matter to hard wire a different replacement in.

You need to measure the coil resistance (it says its a 24 volt coil on the relay) and choose one with similar or higher resistance. If it was much lower then it may not operate correctly or overload the relay driver transistor. Seeing the circuit of the relay driver would help in that case.
 
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Lets be sure...
Monitor the DC voltage across D412 constantly and see what happens to it when the amp fails.

The joint highlighted is typical of one that could become a problem The solder is "crusty" around the component lead and looks to have formed an inner ring. Thats absolutely typical of a dry joint and you will almost certainly find these throughout the amp. R401 is a 3 watt resistor feeding the relay. Check the joints on it.

If the 24 volts relay drive voltage is present across D412 then you are going to have to "make" a new relay fit either by hardwiring or by drilling the PCB to accomodate a different pin spacing.
 

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Hi, i have an su-v505 with noise in left channel. I checked the power and pre transistors and everything its ok. I'm note two resistor in vamp plate that not comes in service manual which are damaged.
could you please help me by testing in your 505 the value of the two resistor?
 
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