Restoring a Kenwood KR-9050

I get nothing on the FM signal meter, regardless of where I set the antenna. The FM tuning meter is centered, doesnt move. I will have to look closer at the antenna board connections, but that will require some disaseembly...so I'll check back in in a bit
 
Is the +12V supply through S1 making it to the tuner section? The supply is switched between AM, FM, or off when those functions are not active.
 
Watthour: not sure. By the way, where is the Valley of Chief Black Hawk?

Also, is this normal? a green wire running from the tuner board to the tuner dial weight? Where should this wire go?

First image, green wire headed to inside of tuner dial weight, second image the location the green wire attaches to tunerboard. Last image is a zoomed-out image of the tuner board and the green wire's post circled to give a better idea of its location. Any ideas?
 

Attachments

  • image1(1).jpeg
    image1(1).jpeg
    27.8 KB · Views: 36
  • image1(2).jpeg
    image1(2).jpeg
    79 KB · Views: 34
  • image1(3).jpeg
    image1(3).jpeg
    78.8 KB · Views: 34
Watthour: not sure. By the way, where is the Valley of Chief Black Hawk?

Right about here:


iu
 
Last edited:
That green wire is probably a touch sensor used to temporarily disable the AFC function of the tuner while the operator is fine-tuning the set. It is similar to that on a Pioneer SX-1980. If that is the wire, it should be connected to Pin 27 on the tuner board.
 
the 10 amp fuse holder is broken. looks like I need to start there. beyond that, the wires look to be secure on the supply near S1, short of floating the solder
 
So, from what I can tell, there is power all the way through the light rail and to the FM board. But, I'm not sure how to verify this:

"Is the +12V supply through S1 making it to the tuner section? The supply is switched between AM, FM, or off when those functions are not active."

What would you suggest? If I put a voltage emter on it, can I use the chasis as a ground? I have a basic 29 range multimeter.
 
The lamps are incandescent, they have no polarity and run on AC. You replaced them with LED's that are polarized and would typically require a current limiting resistor at a minimum. LED's are still diodes and if you place a diode across your AC line in the wrong way that's also running to the tuner I am not sure what would happen, especially if you did not limit the current. The LED's may have nothing to do with the tuner issue.

What is the part number of the LED you used and can you show a picture of how you wired them up?

On my receiver I created a small circuit to rectify the AC to DC in order to drive the LED's. This prevents the LED's from flickering. The circuit consists of some small diodes, a capacitor and a resistor to limit the current. I have the receiver apart so I could look and give you more details on what I used.

I am sure that I used this and the note on the bag shows what the rectified voltage would be. The 6 LED's are all wired in series with a 120 ohm resistor.

39628709135_c69fc4dc5e_b.jpg

38713806560_ca367b79be_b.jpg

One thing I'm not following on this post is whether or not you used the little green risistor or the black ground jumpers on the LED string. In your picture, they are still laying on the old white paper piece. And in the LED string, is positive on the left or right of each LED?
 
also, according the the schematic, the reistor is 1 ohm 1 watt, correct? Here is how its labeled:

upload_2019-2-27_9-33-32.png

and the note on the manual describing the resistor ratings

upload_2019-2-27_9-34-28.png
 
I removed the resistor on my installation but I have a current limiting resistor on the LED string.

Does the AM tuner work? If so the power to the tuner is probably ok.

Did you check the antenna board?
 
I removed the resistor on my installation but I have a current limiting resistor on the LED string.

Does the AM tuner work? If so the power to the tuner is probably ok.

Did you check the antenna board?

The AM does not tune anything in, its just fuzz. The tech I had recap the unit said he couldn't fix it which I was fine with because I wont listen to AM. However, I want to replace the existing resistor with a new one because I am going to go back over my relamp work over the the dial/meter string to clean up my soldering, and the existing resistor has really short leads making it hard to solder. I'd like to replace it in that process.

I did look at the antenna board but dint find anything unusual. The biggest reason that suggestion is confusing to me is that the FM tuner worked fine (again, AM was just fuzz) before I attempted the relamp, and I'm unsure what I could have done to disrupt the antenna board considering I was never working around it. Certainly worth another closer look, I appreciate the suggestion.
 
Last edited:
Back
Top Bottom