JVC QL-7 Counterweight Rubber Bushing

[john65b]

Hey all,

First time posting here on TT forum, so forgive me if I don't get the lingo correct.

Had a pile of Albums from years back and wanted a descent TT...Had a B&O TX-2 with an MMC3 cartridge and was happy.

I saw a posting for a JVC QL-7 and remembered a friend having one years ago and I always loved its look and how it sounded, so I bought it.

After getting it home I realized that the counterweight was drooping and a little pile of rubber powder under that bushing. I looked at the bushing and the bottom side was shallower than top, so I tried to roll the bushing so the shallow part was on top. That helped a little, but still dropping.

I can't see how to remove/replace the bushing, or know where to get a new one...any help?

I will post pics later. Still a beautiful TT!

 

[john65b]

Well that was really a non event...I took apart the counterweight and pulled what was left of the bushing and went to Menards. Matched and bought a rubber faucet washer that was flat on one side and tapered on the other (size "0" - 17/32" OD) and put it all back together. Counterweight now straight and perfect again.

Sometimes I really impress myself. Too bad the wife thinks I am a total dork-wad.

 

[quicksand]

John, the bushing in my tonearm hasn't deteriorated completely - I still would like to do the repair and return it to horizontal.

Took the counterweight off and it isn't obvious how to replace the grommet without cutting away at the old one and splicing the new one in place. I have read that there is a pin that supports the counterweight and the bushing is just for isolation.

Could you please elaborate on the repair.

Thanks!

 

[john65b]

OK, I am doing this from memory... completely remove the counterweight from the arm. The arm side threaded shaft will turn, so you have to pull and turn off the Counter Weight, or just hold the shaft with pair of pliers to keep the shaft from rotating. Once counter weight is off, the remaining portion of the rubber bushing can be removed. An "0" sized water valve washer from Menards (the one that has one side like a funnel) should be inserted over the shaft (you may have to drill out the center a bit to make a nice fit. The funnel side should face toward the arm. Rethread the counterweight back onto shaft (pulling and turning, or hold the shft with pliers to keep shaft still). The counter weight should be snug, but not to tight. You just want to keep the counterweight from sagging...you may have a little issue getting the arm to balance at zero as the counterweight may "hang out" further than the original...

Hope this helps...

EDIT - just reread your post - looks like you already have the counter weight off...juts continue to pick away at the old bushing to remove it. You may need an x-acto knife to remove it completely...then just slide new one on...

 

[quicksand]

Replacing the bushing/ grommet is where I am lost. I haven't removed the old one yet - wanted to confirm the process first. I picked up the "0" beveled and the flat style washers and the flat is an almost exact thickness and OD. Since it is the same outside diameter how do you get it into place without splicing/ cutting it to fit over arm? The arm doesn't appear to disassemble.

 

[john65b]

Hey, no problem. The arm does disassemble from the counterweight - there is a threaded shaft connecting the arm to the counterweight. They should thread off - like I said, the shaft will rotate with the counterweight freely in the arm, and on my unit, the existing busing was 95% gone, leaving a obvious, nasty droop of the counterweight. I could see the threaded shaft rotate freely with the CW. To disassemble the arm from counterweight, I pulled the counterweight away from the arm and un-threaded the counterweight.

Once the existing bushing is removed, you will see the shaft inside.

You do not need to splice the new bushing, as the arm and counterweight will come apart.

I apologize as I am remembering this from memory...

 

[john65b]

OK...Hold on...I found a video I made for the buyer when I wanted to make sure I wasn't going to get nailed for shipping damage (shipped and arrived fine, BTW)...download the following vid. You will see the arm counterweight completely off the arm. Have you done this yet?

http://suburbansurvey.no-ip.org/clip0016.avi

 

[john65b]

Once counterweight is completely off (like in vid), you will find a tiny threaded pin holding the counterweight shaft onto the arm shaft. Remove threaded pin and the CW shaft should rotate off the arm shaft...

Again, from bad memory...I don't know why I have been unsuscribed to my own thread...I will resubscribe...

 

[quicksand]

Thanks for your response!

I have the counterweight off and the shaft doesn't seem to turn easily in either direction. I am hesitant to pick out the old bushing since the table is my main unit. I feel a small hole under the arm near the pivot point though. Will have to explore this more.

You sold your table - I assume you upgraded?

Again, I appreciate the help.

 

[john65b]

The hole under the arm is a little threaded stud that has an allen wrench hole. Loosen it and you will be able to remove the CW shaft.

Yes I sold it for a Denon 62L....don't know if it really was a move up tho...I miss that TT

 

[quicksand]

That is what I figured - just wanted to confirm since it is my daily driver.

Odd thing is the bushing doesn't seem to be deteriorated.

An externally hosted image should be here but it was not working when we last tested it.

Thanks again for the direction - I will report back.

 

[john65b]

I had black dust from the rubber all over my table - made a mess. Yours look as bad as mine. The bushing gets real soft and can no longer hold up the CW.

I think the CW shaft may turn, allowing you to loosen that threaded stud from up top instead of where it is at now...

 

[quicksand]

The counter weight shaft will not turn and I can not find a metric hex wrench that will fit! Been to 2 local stores and only have the 1.5mm key. From what I can tell I need to visit a hobby shop to get the fine electronic set with .7, .9 or 1.3mm wrench.

keep you posted...

 

[john65b]

Its a tiny allen. I remembered that much. I luckily had one. Smaller than a toothpick, right?

 

[quicksand]

Yeah, like nothing I have seen before - though if I had a square tooth pick...

Going to pursue it more tomorrow at a hobby shop.

Wiha Precison Hex Screwdrivers Inch & Metric $28 + $9 to ship it doesn't seem right for something I will only use once.

 

[quicksand]

I ordered a less expensive complete set of Fuller SAE/ MM Allen wrenches that arrived today and either they are sized wrong or the stud is an odd size. The wrenches work for different parts of the arm just not the counterweight stud.

On further inspection the grommet extends into the arm in both directions where as the facet washer would just sit between the two parts. I might have to step back and reassess taking this arm apart - not sure how much the bend affects playback and since it is intact I am tempted to just leave it.

 

[quicksand]

John, I cant let this rest... mind looking at your allen set and tell me if you have something other than .7, .9, 1.3, 1.5mm wrenches? The 1.3 is close but spins inside the head. I am considering buying a quality 1.3 that is possibly more accurately sized unless you have something different.

Thanks!

 

[john65b]

I cannot remember if the one I have was the one - Its the smallest one I have, and it says 1/16. I just don't remember if this is what I used...

 

[quicksand]

Thanks for all the help - cheers!

 

[Van_Isle]

There's a group of us over at Audiokarma interested in this same issue.

quicksand, have you made any progress?