Nikko Alpha 440 Repair And Restoration

This Nikko Alpha 440 power amplifier is forty years old and is in need of some service.

The top cover of this Nikko Alpha 440 is a little scratched up but is in decent shape.

The bottom cover of this Nikko Alpha 440 power amplifier is in good shape.  

After removing the top cover I can see that there will be some cleaning to do.

Almost all vintage audio repair or restorations involve a lot of cleaning. This Nikko Alpha 440 is no exception.

Pretty much everywhere on the chassis there is years of dirt and grime that needs to be removed.

I have now removed the bottom cover, The same story here. A lot of cleaning to do.

The power transistors are also pretty much covered up with grime.

I will take this Nikko Alpha 440 power amplifier outside to clean it up as it would make a mess to clean it inside.

I have removed most of the heavy grime and dirt from the chassis of this Nikko Alpha 440 power amplifier.

I will now power up this Nikko alpha 440 for the first time on a variac and a dim bulb tester.

It is important to power up any unknown vintage audio equipment with caution.

I'll be replacing the 40 year old electrolytic capacitors with modern high quality capacitors.

Old electrolytic capacitors are the leading cause of circuit failure in vintage audio equipment sometimes causing extensive damage.

I have removed the faceplate during this Nikko Alpha 440 power amplifier repair and restoration.

With the faceplate removed it's much easier to clean it properly.

In the picture below I have touched the LED meter assembly with my finger to better show the level of grime that needs to be cleaned up.

The power supply of any piece of vintage audio equipment is the most important assembly.

If the power supply fails and you are lucky the unit just doesn't work. If you are unlucky a power supply failure may cause extensive damage.

Once again those 40 year old electrolytic capacitors must be replaced so that this Nikko Alpha 440 can be reliable in everyday use.

During this Nikko Alpha 440 repair and restoration I will also inspect the artwork side of the assemblies for any solder joint issues.

I'll now do capacitor changes on the main amp assembly during this Nikko Alpha 440 power amplifier repair and restoration.

This Nikko Alpha 440 has some Bi-Polar capacitors. 40 year old Bi-Polar capacitors should be replaced.

I have reinstalled the main amp assembly after doing the upgrade work during this Nikko Alpha 440 repair and restoration.

I have started to remove the heatsink assemblies during this Nikko Alpha 440 repair and restoration.

The heatsink assemblies are pretty dirty and with them removed from the chassis they will be easier to clean up.

With the heatsink assembly removed I am able to access the power transistors and the interface assembly that connects them to the heatsink.

With the interface assembly removed from the heatsink I'll be able to clean it and inspect the artwork side for any issues.

I'll be installing new insulators and thermal compound but first I'll need to clean up the old thermal compound from the power transistors.

The old insulators will be removed from the heatsink assembly. After cleaning I'll install the transistors along with the new insulators and thermal compound.

I have cleaned up the old thermal compound from the transistors. This Nikko Alpha 440 power amplifier is getting closer to getting back in service.

I have also cleaned up the artwork side and inspected the power transistor assembly for any solder joint issues.

I have cleaned up the heatsink assembly. Any vintage audio repair or restoration involves a lot of cleaning.

I'll be using new insulators for the power transistors. This Nikko Alpha 440 is getting ready to start it's next 40 years of service.

I have reassembled the power transistor/heatsink assembly and I'm about ready to install it back into the chassis.

These power transistors are the original one's that left Japan 40 years ago. Hopefully they will last another 40 years.

The two electrolytic capacitors on the output transistor assembly were replaced during this Nikko Alpha 440 repair and restoration.

The electrolytic capacitors were replaced with Kemet film capacitors.

At the back of the Nikko Alpha 440 power amplifier sits the input assembly which also needs attention.

Once removed from the chassis the level controls and the direct/normal switch can be cleaned with deoxit.

There was also one Bi-Polar capacitor that was replaced. This capacitor is in the audio path so it can make a difference in the amps sound.

With back panel down of coarse there is more grime to clean up in this Nikko Alpha 440 power amplifier.

I've got it cleaned up. This Nikko 440 is getting to start it's next 40 years of service.

WARNING! HAZARDOUS ENERGY! I'm not sure that I have seen this on the back of any other vintage audio equipment.

The relay assembly had the only electrolytic capacitor on it replaced.

With a new Nichicon PW series capacitor installed this assembly should work well for many years.

I have reinstalled the assemblies and tie wrapped the cabling back up neatly. This Nikko Alpha 440 power amplifier is ready for bench testing.

I'll use a couple 8 ohm 300 watt load resistors for bench testing of this Nikko Alpha 440.

Everything looked good on the test bench. I set the bias and DC offset to specifications using the service manual.

This Nikko Alpha 440 power amplifier repair and restoration is complete. It's time for some music!

 

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