CR-620 Old Age Issues?

Hi, I am new to this forum and by no means am I a techie or audiophile.

I've had a CR-620 since the early '70s and its been a wonderfully reliable tuner/amplifier for all my musical needs...until recently.

I am having two problems with it and in looking through the threads here, I think they may be relatively common. But I need some advice on what's going on.

First, in the past week, I've been hearing "pops" or "clicks" when I am tuned into any radio station. They are making it so that I can't keep the receiver on. If I tune into the station precisely, sometimes the clicks stop, but they generally come back. The sound remains on through the clicks. The clicks are sporadic - maybe every 10 seconds or so - not very fast, but unnerving after a short while.

Does anyone know what this might be?

Second, over time, the tuning dial has become harder and harder to turn. It is almost to the point now that it takes great effort to move the dial.

I've seen some comments about a stiff tuning dial, but I am wondering what the consensus is here on what's making this happen and how/whether it can be rectified.

As I said, I am not a qualified technician, nor a hobbyist. So, I am in the Chicago suburbs and I am wondering whether anyone reading this has a recommendation on a shop that would be able to take a look at this and perhaps do some work to bring it back to good life - if these are signs of aging and suggesting that a "tune-up" or physical might be in order.

Any help and comments would be appreciated by this newbie here.

Thanks,

Eric

I've seen some comments about a stiff tuning dial, but I am wondering what the consensus is here on what's making this happen and how/whether it can be rectified

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The tuning shaft is just gummed up.To repair it correctly it needs to be disassembled,the shaft and bushing thouroughly cleaned . Acetone works great! Then relubed with a light coat white lithium grease.Once reassembled it will spin like a top!!!

Do you get the pops and clicks while using the AUX,PHONO or TAPE inputs?Are you using and external antenna? FM muting on or off?

avionic said:

The tuning shaft is just gummed up and needs to be disassembled,thouroughly cleaned and relubed with a light coat white lithium grease.Once reassembled it will spin like a top!!!

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I used gun oil
Worked great
It would be possible to use a penetrating lube like WD and after taking the knob off and tipping it on its back let it soak down the shaft but dont use very much
If I had it to do over again I would do it that way because I hate messing with tuner string
It is sticking between the metal shaft and a nylon bushing and its just dried out
Lettin WD run down the shaft while turning the knob should do it but you dont want WD or anything like that on the guts
You cant be in better hands than you are with your other problem

Must be a drive by OP

Sorry - not a drive by!

Jpowell1 said:

Must be a drive by OP

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Sorry, I am used to these kinds of boards sending me an email when a reply is received, and I didn't get any - so I decided the check in again today and I saw your replies.

I just saw the "thread subscription" option setting, and I have set it for instant notification, so, I will be more aware of when responses are needed.

I will try the WD40 lubrication on the tuning wheel. I won't use a lot and I will let you know what happens. I am nervous about even taking the knob off, but your encouragement has given me the guts to do this...

And as I try, gently, to pull the knob off, it isn't budging. Do you recommend that I try using something like a screwdriver to wedge/lever it off?

So, I will wait for your suggestion on how to get the knob off.

Thanks,

Eric

Pops and Clicks

avionic said:

Do you get the pops and clicks while using the AUX,PHONO or TAPE inputs?Are you using and external antenna? FM muting on or off?

Click to expand...

Well, I don't have a turntable hooked up, but the CD played perfectly without pops thru the AUX.

I am using an antenna - just the wire antenna that - I think - came with the receiver. But it is helping, as I move it around the signal quality changes.

What is most interesting is that I found that the signal has been coming in with FM muting off, but when I change the setting to on, I can no longer tune stations in well, no matter what the signal meter tells me about the signal. So, when the station is coming in well with FM Muting off, I can't get the station well with it on anymore. And I can only hear the station at all with FM Muting on if I turn the volume up significantly.

By the way, this evening, with FM Muting off, I am listening to FM radio with no pops.

Does this help at all?

Thanks,

Eric

Wonder if the muting circuit needs and adjustment? Other will chime in, maybe the adjustment is on the edge of muting and why the pops are happening. Service manual should have the muting adjustment and what pot to turn.

If it's like my CR-220, there's a set screw that's only visible once you remove the metal cover - it's behind the plane of the metal face. I tried to pry mine off too, but another AK'er alerted me to the set screw.

I had the hard to turn wheel as well. I was ready to partially disassemble and lube, but somehow it broke free during my attempted disassembly and now spins nicely. I just got lucky.

But pry no longer - look for the set screw.

Good luck.

Echoch said:

Sorry, I am used to these kinds of boards sending me an email when a reply is received, and I didn't get any - so I decided the check in again today and I saw your replies.

I just saw the "thread subscription" option setting, and I have set it for instant notification, so, I will be more aware of when responses are needed.

I will try the WD40 lubrication on the tuning wheel. I won't use a lot and I will let you know what happens. I am nervous about even taking the knob off, but your encouragement has given me the guts to do this...

And as I try, gently, to pull the knob off, it isn't budging. Do you recommend that I try using something like a screwdriver to wedge/lever it off?

So, I will wait for your suggestion on how to get the knob off.

Thanks,

Eric

Click to expand...

captouch said:

If it's like my CR-220, there's a set screw that's only visible once you remove the metal cover - it's behind the plane of the metal face. I tried to pry mine off too, but another AK'er alerted me to the set screw.

I had the hard to turn wheel as well. I was ready to partially disassemble and lube, but somehow it broke free during my attempted disassembly and now spins nicely. I just got lucky.

But pry no longer - look for the set screw.

Good luck.

Click to expand...

Cap,

Thanks for the alert on this - but I am having a hard time finding the set screw. I am not sure which "metal face" you're referring to.

The knob/dial seems to be one-piece. I don't see a faceplate on the knob/dial. I was thinking that the top of the knob might be a removeable faceplate, but it doesn't seem to be 2 pieces. IF I am wrong, any advice on how to pry the faceplate/cap off would be helpful.

Otherwise, if you, or someone else reading this, could give me some more of an idea about the faceplate- or whether the CR-620 even has ta faceplate, that would be a great help.

thanks,

Eric

Echoch said:

Cap,

Thanks for the alert on this - but I am having a hard time finding the set screw. I am not sure which "metal face" you're referring to.

The knob/dial seems to be one-piece. I don't see a faceplate on the knob/dial. I was thinking that the top of the knob might be a removeable faceplate, but it doesn't seem to be 2 pieces. IF I am wrong, any advice on how to pry the faceplate/cap off would be helpful.

Otherwise, if you, or someone else reading this, could give me some more of an idea about the faceplate- or whether the CR-620 even has ta faceplate, that would be a great help.

thanks,
Eric

Click to expand...

The faceplate is the big rectangular aluminum thing with YAMAHA NS CR-620 silkscreened on it... Access the setscrews from the side of the unit with the wooden bonnet removed...

I had a feeling that was the faceplate. I will try to extract the unit from the wood bonnet. I've never done that before, but I'll give it a try.

thanks,

Eric

Echoch said:

I had a feeling that was the faceplate. I will try to extract the unit from the wood bonnet. I've never done that before, but I'll give it a try.

thanks,

Eric

Click to expand...

Remove 4 or 5 large screws with large square washers on the bottom. Slide chassis out of the bonnet.

I probably confused you with "metal cover" and "metal face" - the CR-220 doesn't have a wood cover/bonnet, it's metal. And I should have said faceplate instead of metal face.

Good luck.

There are 5 screws on the bottom that go through large washers with the corners turned up into the wood One at each corner and one in the middle
Remove those 5 screws and slide the receiver forward a few inches
and look at the side with the tuning knob
As you turn the knob you will see what looks like a hole on the part of the knob behind the face plate
That hole contains a 1.5 or 2 mm set screw
Loosen that set screw and the knob will come off easily
When the set screw lets go it always seems to click
If you loosen too far the screw will come completely out and then you get to search for it on the floor and it is tiny
Tip the receiver tipped up on its back and let the WD or whatever you are using run down the shaft while turning it
based on your posts I think it best to try this method before attemepting removing the shaft

That hole contains a 1.5 or 2 mm set screw

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Usually there are 2 setscrews approx. 90 degrees offset from each other.:thmbsp:

avionic said:

Usually there are 2 setscrews approx. 90 degrees offset from each other.:thmbsp:

Click to expand...

As always
You are correct

Jpowell1 said:

As always
You are correct

Click to expand...

Not always...

Maybe not always correct but never wrong
I was just worried he was trying to pry it off as I was typing
I wonder what would let go first
The set screws on the knob or the shaft come out