CR-640 tuning meter not deflecting

[wa27]

I've got a CR-640 and the tuning meter hardly moves at all. I've read that the deflection on these is always lower than you'd expect, but there is obviously something wrong with mine. It deflects about 1 mm either way.

I can tell it's working to some extent, because I can still use it to "dial in" a station if I use a magnifying glass. The voltages going into it are +- 80mV, but I can't find out what they should be. Maybe it's just too low of voltage? I did notice the Signal Strength meter (which is working) has higher voltage going through it. Is there a way to adjust the voltage to each meter?

I tried reading the service manual, but it wasn't very clear. It looks like I can adjust the discriminator to adjust the center point (which I need to do also), but I don't see anything that adjusts sensitivity/deflection amount. Anyone have any experience with this issue? I assume it would apply to the CR-1040 and other CR-XX40 models.

 

[clinic-audio]

Hello

I assume it would apply to the CR-1040 and other CR-XX40 models

This will be true if the signal meters are the same in all models and this is not the case . Look around tuning circuit and if you are in good reception conditions !. this low deflection is probably normal .
Don't forget that this meter is a signal Q meter not a signal strengh meter . If you are not in perfect reception conditions you will not have full deflection of the meter . The quality of the sound will be poor and this meter will confirm that . Yamaha think that we don't mind to receive strong signal if it is bad quality signal . Quality meter indication is more clever . This is a patent made by YAMAHA on all their tuners .

 

[chazix]

I think wa27 is talking about the center-tuning meter, not the signal strength/quality meter. I have to confess I don't understand the circuitry around the center-tuning meter, but it sure doesn't look like there is an adjustment for deflection magnitude.

Not very helpful, I suppose - sorry!

chazix

 

[wa27]

Chazix is right. It's the one labeled "FM Tuning". I had the same dial on my old Pioneer SX-780 and it was helpful for tuning a station in. If the needle is leaning left, tune the knob to the right and vice-versa. So for a perfectly tuned station it would rest in the middle (and it would re-center when completely de-tuned).

this one hardly moves at all. I wasn't exaggerating when I said it only moves about 1 mm in either direction. It does move left and right when appropriate, but the deflection is like 1% of what it should be. If you don't bring your face right up to the glass, you can't tell it's moving.