Nakamichi 410 pre amplifier - need help on sensitivity selector

[tareq2163]

Hi,

Can anyone help me on how to fix this ?

I just got this beautiful sounding Nakamichi 410 pre-amp. It has a selector in the back to selct different sensitivity of cartridge. But when I move the selector button up or down, the sounds get weakened in right channel. If I fiddle it a bit, soemtimes it gives correct balance but sometimes it doesn't. What do I do ?

Please help!!

 

[malden]

Unplug the preamp, remove the cover and give it a few shots of Deoxit while working the switch up and down...

http://www.parts-express.com/caig-deoxit-d5s-6-spray-5-oz--341-200

 

[Freddymac2]

You also have to look up the output of your cartridge, so you don't overdrive your phono stage. If you use the 1 mv sensitivity on a 5 mv cartridge you may cause distortion. That is a small signal and any dirt or corrosion may kill some of the signal. I find that if you can get to the switch body, two treatments are better than one, spaced over two days or so. The deoxit evaporates quickly so when you squirt it move the switch immediately, many times through all three positions. I would follow up with a fader lube but some here may not agree.

 

[tareq2163]

Thanks ! I did the same with a Philips regular contact cleaner. But still it doesn't work out. If I touch the switch again, the sound gets distorted. Also, now I am hearing a slight 'zzzz' type noise in both the speakers although I have connected the ground wire properly with the amp. Can you help me please ? And what is a fader lube ?

You also have to look up the output of your cartridge, so you don't overdrive your phono stage. If you use the 1 mv sensitivity on a 5 mv cartridge you may cause distortion. That is a small signal and any dirt or corrosion may kill some of the signal. I find that if you can get to the switch body, two treatments are better than one, spaced over two days or so. The deoxit evaporates quickly so when you squirt it move the switch immediately, many times through all three positions. I would follow up with a fader lube but some here may not agree.

with

 

[Freddymac2]

I am not familiar with the philips contact cleaner, but any should work. Fader lube is an oil that replaces some of the lubricant that you washed out when you used the contact cleaner. If you can get both channel working at any point then, it could be bad corosition or a bad switch, or solder joint. If you have an ohm meter (with the unit unplugged) get to the point where the switch is soldered to the board and look at the resistance across the contacts, of each setting. Does one switch setting pas a signal more often. Some of these Nak's had bad solder joints, that may need to be reheated. For the moment don't worry about the ZZZZ, where was the volume Knob when you heard the noise. What kind of TT do you have? Where are you? Is the problem always with the same channel. .You can not get spry into the switch from the outside you must flush the contacts from the inside of the switch

 

[tareq2163]

I am not familiar with the philips contact cleaner, but any should work. Fader lube is an oil that replaces some of the lubricant that you washed out when you used the contact cleaner. If you can get both channel working at any point then, it could be bad corosition or a bad switch, or solder joint. If you have an ohm meter (with the unit unplugged) get to the point where the switch is soldered to the board and look at the resistance across the contacts, of each setting. Does one switch setting pas a signal more often. Some of these Nak's had bad solder joints, that may need to be reheated. For the moment don't worry about the ZZZZ, where was the volume Knob when you heard the noise. What kind of TT do you have? Where are you? Is the problem always with the same channel. .You can not get spry into the switch from the outside you must flush the contacts from the inside of the switch

The zzzz sound is present in all volume settings, more audible with hugher volumes, in both the channels. I live in Bangladesh. My TT is Pioneer PLx 1000.. i did the sprays after removing the covers and exactly the manner you you suggested. Pls help.

 

[Freddymac2]

do you get the zzzzz only on the phono setting,

 

[Freddymac2]

Do you have a good volt ohm meter Can you make shorting plugs for the phono RCA sockets.

 

[tareq2163]

Ye

do you get the zzzzz only on the phono setting,

yes, only with phono connection!

 

[tareq2163]

Do you have a good volt ohm meter Can you make shorting plugs for the phono RCA sockets.

I have a volt meter, can you guide me how to test it ?