Nikko power amplifier alpha II relay

[kocozze]

Hi all,
sorry for my bad english.
I have a Nikko power amplifier alpha II (vintage amp - late 1970).
I need to replace the relay (the "click" is too small, does not reach the correct power at loudspeakers). Have you an idea of which relay i must buy?

Many thanks

 

[Mooly]

Many relays can be opened up. Maybe worth looking at and seeing if the contacts can be cleaned.

To replace the relay you need to know the pin configuration and the electrical characteristic, the coil voltage and resistance.

 

[kocozze]

Thanks, i've already open and clean the contact of the relay.
Did you know where I can found the specs of the relay and wich relay i can use for substitute the original one?
Perhaps the problem that stop the "click" is not the relay and is the elctric caps?

 

[Mooly]

You would have to measure the coil resistance and voltage across the coil when activated and then start looking for replacements based on that. If there is a drive fault to the relay then it may not be getting the correct voltage to pull in.

Do you have sound from the speakers ? If you do then the relay is at least closing. If you don't then it might be a power amp problem (dc offset) that is stopping the relay operating and its actually doing its job correctly.

 

[kocozze]

I have sound from speaker...this means that the relay is perfectly close?
Because i turn on the volume knob much higher than before of this problem for the same exactly level of sound....

 

[Mooly]

Not quite understanding the last bit

Do you mean its not as loud as it used to be for a given setting of the volume control ? or has turning it higher "fixed" the problem ?

 

[kocozze]

Both, at 9.00 a.m of volume knob i have a lowest decibel than before, and if i turn the volume knob the volume increase...! Even the sound quality seems worse than before (lowest dynamic of bass). Sorry for my english.

 

[Mooly]

That sounds like it needs proper tests to see whats going on (using a scope).

Are both channels the same ? You can prove if the relay is faulty by shorting it out but if you do then connect the speakers manually after switching on and disconnect them before switching off. Both channels though, well that doesn't really sound like the relay tbh.

It needs a proper tests with a known source

 

[kocozze]

ok my english is a terrible limit...what it means "shorting it out"? You suggest bypassing the relay connecting manually the speaker without the relay in place?

 

[Mooly]

Yes, bypassing the relay would prove if it was faulty but you would have to be sure you knew exactly which points to short out. Get it wrong and it could prove disastrous.

 

[kocozze]

i will careful...having said that, i have a last minute update. I turn it off all!! With no music in play the right channel makes strange noises intermittent, with the Vu Meter right that rises and falls many time, alone, without any input...oh oh, it's better that i do not use anything?

 

[Mooly]

Its very difficult to say what is going on with it at a distance. Given the age of it you might have problems with old electrolytic capacitors having dried out, and problems with dry joints (poor soldering).

The only answer I'm afraid is to test it properly with a scope and signal source to determine what is happening.

The output relay is a very specific part and gives specific faults, but if you are doubtful over it then you have to eliminate it.