Nakamichi ia-2 help

[ftpols]

Hi,

I just purchased a used Nakamichi IA-2 amp. Nice piece of gear but there is a very loud buzz from LH channel when switched to Phono and there is no signal source. (All other selection are silent.)

Also, the trouble and strife says the reproduction is metallic...

Could somebody kindly advise about troubleshooting?

Many thanks!

Ftpols
:tresbon:

 

[avionic]

Hi,

I just purchased a used Nakamichi IA-2 amp. Nice piece of gear but there is a very loud buzz from LH channel when switched to Phono and there is no signal source. (All other selection are silent.)

Also, the trouble and strife says the reproduction is metallic...

Could somebody kindly advise about troubleshooting?

Many thanks!

Ftpols
:tresbon:

LH Phono jack might have a cracked solder connection on the ground.

 

[ftpols]

LH Phono jack might have a cracked solder connection on the ground.

Many thanks for your kind advice, Avionic.

I connected shorting plugs to the phono inputs and a cable from the GND terminal to grounded mains socket. I also sprayed Electrolube in the MM/MC phono selector switch and operated it 20 times.

With the phono MM/MC selector switched to MM, there is a whisper of white noise/pink noise from the left channel at full volume. When the phono selector is switched to MC, however, white noise/pink noise is very prominent on left channel at low volume.
Otherwise the amp is fine. It's years since I used an MC tone arm and turntable, so I guess it's no big deal.

Now I will open it up and check the solder connection on the ground.

Cheers!