QX-949 Receiver Scope

[user 4023]

Hi All.

Found this great forum through AudioKarma. I have recently purchased a QX-949 and have a question about the scope function. All four lights on the scope come on but the left front does not move like the other 3. I'm just getting under the hood of this thing. Can anyone explain to me how the scope lights function. Since the left light comes on but then doesn't move is there something specific I should be addressing. It looks like a PITA to work on since the dial string is there and it is quite a tight fit.

Any help would be appreciated.

Gary

 

[Decoder Man]

Hello Gary,
First thing you must do is recognize the fact that it is not a scope but four meters made to appear as a scope. Each bulb is surrounded by what can best be described as an aluminum foil cork screw. As current increases, the D'Arsenval movement causes the foil to rotate exposing more and more of the lamp. It is no different than a VU-meter.

First you must determine if the meter is functional. With a length of wire, jumper the input to one of the other three meters to this meter. If it moves your in luck. This means the meter is good and the problem is in a circuit board component; most likely a transistor.

If your curiosity forces you to physicaly see the meters. The four meters are enclosed in a plastic housing. You must remove the escutcheon (front panel) to gain access. If you open the meter housing. Be careful to not touch the foil. It is very delicate and bends easily.

By the way. If it is a defective meter, your out-of-luck.

I did this from memory so if someone sees an error please don't hesitate to jump in and make a correction.

Dave

 

[user 4023]

Hello Gary,
First thing you must do is recognize the fact that it is not a scope but four meters made to appear as a scope. Each bulb is surrounded by what can best be described as an aluminum foil cork screw. As current increases, the D'Arsenval movement causes the foil to rotate exposing more and more of the lamp. It is no different than a VU-meter.

First you must determine if the meter is functional. With a length of wire, jumper the input to one of the other three meters to this meter. If it moves your in luck. This means the meter is good and the problem is in a circuit board component; most likely a transistor.

If your curiosity forces you to physicaly see the meters. The four meters are enclosed in a plastic housing. You must remove the escutcheon (front panel) to gain access. If you open the meter housing. Be careful to not touch the foil. It is very delicate and bends easily.

By the way. If it is a defective meter, your out-of-luck.

I did this from memory so if someone sees an error please don't hesitate to jump in and make a correction.

Dave

HI Dave.

Thanks for the response.

I actually figured it out last weekend. But I went in through the top of the unit with the case off and didn't remove the front panel. One of the meters was defective. You are right those little foil covers bend easily and are a pain in the butt to get back on sometimes. I actually acquired a "parts unit" that had a few working meters in it and used one of those in the other unit. The "scope" really adds to the coolness factor but it wasn't the most fun I've had working on a vintage receiver. Like you said, it was certainly different then I expected it to be once I tore into it.

Thanks again for the response. It looks like you are just down the road from me. I live in Munroe Falls, OH

Gary

 

[Decoder Man]

HI Dave.

Thanks for the response.

I actually figured it out last weekend. But I went in through the top of the unit with the case off and didn't remove the front panel. One of the meters was defective. You are right those little foil covers bend easily and are a pain in the butt to get back on sometimes. I actually acquired a "parts unit" that had a few working meters in it and used one of those in the other unit. The "scope" really adds to the coolness factor but it wasn't the most fun I've had working on a vintage receiver. Like you said, it was certainly different then I expected it to be once I tore into it.

Thanks again for the response. It looks like you are just down the road from me. I live in Munroe Falls, OH

Gary

Hello again Gary,
It is true. I am just down the road from you. However, it is a long road at 1 1/2 to 2 hour drive.
Glad to hear you were able to cannibalize from another unit. I have three QX-949A's requiring service but just have not got around to it.

Enjoy your receiver.
Dave