Yashica Mat 124G focusing knob came loose, any advice for a quick fix?

[Jonahhyp]

Ive just put my first roll through my Mat 124G that i had just got off of ebay a couple days ago. Everything is working fine until this morning when I was shooting a test roll and as i was adjusting the focus, the knob suddenly came loose and didnt engage the focusing mechanism. Now the knob spins freely with no resistance, and no effect on the focusing of my image, my camera is stuck at infinity focus. Anyone have a similar experience? Any advice or knowledge on how i can fix this?

 

[DWThomas]

(This may be a little overwhelming!)

It looks as if there's a nut that retains the focus knob, and also a pin that perhaps limits its travel. I've never been inside my 124G to that extent, so I have no hints for how to disassemble some of that stuff. I had mine CLA'd by Mark Hama a few years back, but it was mostly operational prior to that.

 

[Jonahhyp]

(This may be a little overwhelming!)
View attachment 285714
It looks as if there's a nut that retains the focus knob, and also a pin that perhaps limits its travel. I've never been inside my 124G to that extent, so I have no hints for how to disassemble some of that stuff. I had mine CLA'd by Mark Hama a few years back, but it was mostly operational prior to that.

Thanks for the help, do you think Mark Hama still does repairs? Ive sent an email and have to wait for a response. Im not sure how to get the indicator window off the knob

 

[DWThomas]

I'm not sure how active Mr. Hama is these days. It's been several years -- late 2017 since mine was done. It was a good job, he even fixed the meter and installed a tiny Filister head screw to keep the sync lever from going into 'M' (which can hang up the self timer). I'm thinking his name has popped up more recently on these forums.

 

[Dan Daniel]

Looks as if the outer thin metal ring on the focus knob has two thin slots. You need to grab these and rotate counterclockwise. Sometimes you can simply take a push pin tip or small screwdriver into one slot and lightly apply pressure.

Once this ring is out, the assorted parts will come away, exposing the nut that needs to be tightened.

You'll see that the nut is split with an axle coming up in the middle. You can grind the tips of needle nose pliers to fit, or grind a slot in the middle of a fat screwdriver. I strongly recommend making a tool for this, not simply pushing one side, because as you learned if it isn't tight it will come loose again.

For setting position, you'll see that you can tighten the nut a bit and get enough grab to rotate the knob. Bring the lens board to the back, pretty well touching the body but not under pressure. Then go to an infinity target- distant tree or tower or such, and get the viewing lens focus screen showing focus using the knob. Now loosen the nut and rotate just the knob to the infinity stop.

this assumes that the viewing lens and taking lens are in alignment with each other. Good enough to get you using the camera again.

By the way, most any decent repair person should be able to handle this. This is basic TLR focus setting for most TLRs.

 

[jvo]

......

By the way, most any decent repair person should be able to handle this. This is basic TLR focus setting for most TLRs.

Dan is the one who would know - a great technician!

jvo