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NAD 7140 Tuner Not Scanning

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xyzizzy

New Member
Any ideas or next steps would be appreciated - this is my second amp/tuner repair and first NAD! It's now working well other than the AM/FM tuner section.

When received, there were issues with left channel output and inconsistent mono switching. This was fixed with liberal contact cleaner.

The presets would not switch - I have replaced the supercap as a precaution and to see if it would allow me to change channels.

I've checked all the fuses and they're all happy.

The phono preamp and all of the rear panel seems to be okay, though I don't have an antenna to test signal.

However the tuner does not change frequencies - pressing the up and down buttons does not change the tune for either FM or AM. I have used a MM to check whether the buttons are sending a signal, which they are... But now I'm stumped!

I think I've seen some discussion on replacing XTAL201 - C223 also looks a little bit puffy (see pics). I'm thinking about replacing these, but if anyone has further suggestions for investigation or repair I'd be really grateful.

Cheers!
 

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Check my thread from March 5/2023. There is lots of good info. regarding the tuner in the 7140. Hopefully what I have posted there will help you fix your tuner section.
 
Dony said:
Check my thread from March 5/2023. There is lots of good info. regarding the tuner in the 7140. Hopefully what I have posted there will help you fix your tuner section.
Click to expand...
Thanks for the prompt - I'd seen your thread but hadn't made it past page 1!

The main difference I'm experiencing to you are that the tuning stage does not work for both AM and FM - there is no change on the display when I try to change frequencies.

Honestly I'm pretty chuffed to have everything else working, but the completionist in me isn't happy to leave it without trying a bit more!
 
Dony said:
Check my thread from March 5/2023. There is lots of good info. regarding the tuner in the 7140. Hopefully what I have posted there will help you fix your tuner section.
Click to expand...

One last follow-up - the tips definitely helped!

For me - a closer inspection found a few transistors and a capacitor with cold / broken solder joints - after replacing these parts I had no signs of life.

Then replaced C223 and the tuner is now working acceptably.
 
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