Tuner NAD4220 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 14th December 2013, 01:58 PM   #1
diyAudio Member
 
Join Date: Jan 2005
Location: Oudenbosch
Default Tuner NAD4220

Hello guys,

I have a tuner NAD 4220.
It has no reception. When you push the search up or down it runs up or down but does not stop at any channel.

I set it to a known station at 91.00 Mhz with a big outdoor antenna. But nothing.
Absolute quite from the tuner. Even no noise.

I don't know whether it is supposed to noise or that the noise is surpressed.

I don't have a manual nor a service manual. I tried to search the web but was unable to get hold of a service manual.

I'm want to check the voltages and the scope pictures but without any guide lines it is difficult.

Any suggestions where to begin?

I did see some test points.

Click the image to open in full size.

Click the image to open in full size.

Marc
  Reply With Quote
Old 14th December 2013, 10:08 PM   #2
diyAudio Member
 
Join Date: Aug 2011
Location: Anglet, cote basque
Hello !
I don't know if it can help you, but these Nad tuners can have problems on their push selectors, prone to bad contacts. Check if there's not a problem on your FM/AM selector (I had this problem on an 4150 and 4155 tuners).
Perhaps this can help you :
- NAD Tuner 4220
Michel
  Reply With Quote
Old 15th December 2013, 09:48 AM   #3
diyAudio Member
 
tiefbassuebertr's Avatar
 
Join Date: Jul 2005
Location: D-55629 Schwarzerden
First step is disconnect the "MUTE" function and checking the tuning and operating voltgage at the FM-front-End from Mitsumi.
Check additional the lead between the coax antenna connector at back panel and the FM-front-end.
Service manual you can order from there:
Original Service Manual NAD 4220 Tuner | eBay

Last edited by tiefbassuebertr; 15th December 2013 at 09:51 AM.
  Reply With Quote
Old 15th December 2013, 10:04 AM   #4
diyAudio Member
 
Join Date: Jan 2005
Location: Oudenbosch
Thanks for the replies:
I have esthablished that the up and down buttons are working.
I have checked the voltage on the front end.

It's a mitsumi. Found the servicemanual of the 4225 online.
It seems to be pretty close to the 4220 apart from the antenna connection.
The 4220 has only spring clamp terminals
The 4225 has 300 ohm spring clamp and 75 ohm bus connector. This is as far as I can tell the difference.

I have checked the voltage on the front end.
at 108 MHz its 21.150 VDC (supposed to be 20.50.5V)
at 87.5 Mhz, its 3.016 VDC (supposed to be 3V0.5)
SO that does not seems too be to bad.

This was the first step in the service manual.

Then they start testing with a RF generator. That's something I don't have.
Just a frequency generator up to 2Mhz and a scope.

Any suggestions?

Marc
  Reply With Quote
Old 15th December 2013, 11:36 AM   #5
diyAudio Member
 
Join Date: Jan 2005
Location: Oudenbosch
So I have disable the muting by disabling the signal on Q111.
This prevents Q111 by getting high and thus sound should come (noise at leats)
But it remained silent.....

Click the image to open in full size.

Marc
  Reply With Quote
Old 15th December 2013, 12:42 PM   #6
diyAudio Member
 
tiefbassuebertr's Avatar
 
Join Date: Jul 2005
Location: D-55629 Schwarzerden
Quote:
Originally Posted by f2ride2001 View Post
Thanks for the replies:
I have esthablished that the up and down buttons are working.
I have checked the voltage on the front end.

It's a mitsumi. Found the servicemanual of the 4225 online.
It seems to be pretty close to the 4220 apart from the antenna connection.
The 4220 has only spring clamp terminals
The 4225 has 300 ohm spring clamp and 75 ohm bus connector. This is as far as I can tell the difference.

I have checked the voltage on the front end.
at 108 MHz its 21.150 VDC (supposed to be 20.50.5V)
at 87.5 Mhz, its 3.016 VDC (supposed to be 3V0.5)
SO that does not seems too be to bad.


This was the first step in the service manual.

Then they start testing with a RF generator. That's something I don't have.
Just a frequency generator up to 2Mhz and a scope.

Any suggestions?

Marc
This is the tuning voltage. What about the operating voltage?
the resolution of the schematic is not sufficient to naming the right devices and measuring points.

Last edited by tiefbassuebertr; 15th December 2013 at 12:44 PM.
  Reply With Quote
Old 15th December 2013, 05:24 PM   #7
diyAudio Member
 
Join Date: Jan 2005
Location: Oudenbosch
That's what I find bad on the schematics. There is not a single mention of voltage what so ever. NAD can learn something from most japanese manufacturers.

So I have no clue what the main voltages should be

Only thing I can do is check chip voltage as per specified datasheet and check the voltage on the actual chip itself.

As far as i van tell voltage should be relatively ok since LED is burning like normal and all functions like up / down memory are working.

I can try to enhance the PDF.

Marc

Last edited by f2ride2001; 15th December 2013 at 05:27 PM.
  Reply With Quote
Old 15th December 2013, 05:59 PM   #8
diyAudio Member
 
Join Date: Jan 2005
Location: Oudenbosch
This is as good as it gets.
Attached Images
File Type: jpg hfe_nad_4225_service_en (1).jpg (936.6 KB, 33 views)
  Reply With Quote
Old 15th December 2013, 09:12 PM   #9
diyAudio Member
 
tiefbassuebertr's Avatar
 
Join Date: Jul 2005
Location: D-55629 Schwarzerden
Quote:
Originally Posted by f2ride2001 View Post
That's what I find bad on the schematics. There is not a single mention of voltage what so ever. NAD can learn something from most japanese manufacturers.

So I have no clue what the main voltages should be

Only thing I can do is check chip voltage as per specified datasheet and check the voltage on the actual chip itself.

As far as i van tell voltage should be relatively ok since LED is burning like normal and all functions like up / down memory are working.

I can try to enhance the PDF.

Marc
As I already mentioned in post #3 I mean the operating voltgage at the FM-front-End from Mitsumi, according the schematic in your post #8 at PIN 5 (so I think) behind the 2,2 uH inductor (naturally between 8 volts and 12 volts).
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fisher FM-50 tube tuner and Dynaco FM-3 tube tuner hatrack71 Swap Meet 5 25th January 2011 10:43 PM
Larsholt fm tuner front end for JLH tuner design-Any still available? djsb Analogue Source 0 25th December 2008 04:46 PM
For tuner.. Sch3mat1c Analogue Source 11 14th February 2003 06:45 AM
tuner FlMike Tubes / Valves 4 1st May 2002 01:59 AM


New To Site? Need Help?

All times are GMT. The time now is 05:42 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2