JVC Victor Tonearm Counterweight Sag Repair

I picked up some washers at my local hardware store that at least meet the spec of the washers in your photo. The container shownin the photo says "1/2 in OD".  But the washers shown on the right hand side clearly say "1/4 (meaning 1/4 inch) OD".  Although this is ambiguous, I opted for the 1/2 in OD version.  What strikes me, besides the ambiguity in relation to OD, is how hard and stiff these washers are. In fact, I would like to be that hard and stiff.  Can you clear up the question of Outer Diameter?

lewm

Can you clear up the question of Outer Diameter?

"too smart for our own good", you have heard that I expect.

If a washer could clearly SAY, then it would tell you the time hidden mystery contained in the codes clearly MARKED i.e. clearly marked 1/4S

You have erroneously taken the marking ’1/4S’ to mean a diameter. I believe in plumber speak it relates to pipe/valve seat size, here’s several marks which a plumber would understand. The letter (S in our case) may indicate the angle of the bevel.

 

size #00 is 1/2" OD (one half inch outer diameter/diametro exterior)

full text and photos here:

https://www.audiogon.com/systems/12014

The one I used (everbuilt model 866210) (home depot sku 1006959446) has a 5mm diameter center hole which happens to perfectly fit the 5mm diameter shaft of the concealed threaded brass piece. The washer coincidentally happens to be 1/4" overall thickness, the bevel appears to me to approximate a 45 degree slope.

It feels hard, however it is softer than you realize, the force of the counterweight is surprisingly large which is why I noted tighten ’very snugly’ in assembly step C below (otherwise it will sag).

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JVC Victor Counterweight Sag Repair (Tonearms UA-7045 and long version UA-7082)

Three allen head set screws (2 sizes) are involved. (presumably metric, however I bought a 1/16” size key that fit the pair in my arm post that retain the chrome collet).

Only One Repair Part Needed, size #00, ½” OD Beveled Rubber Washer. Note: Inside hole is 5mm diameter, presses onto 5mm diameter brass shaft shown below.

(everbuilt model 866210) (home depot sku 1006959446)

Concealed Brass Piece, 18mm overall length, 8.5mm diameter rubber shoulder fits inside the chrome metal collet, 5mm diameter brass shoulder, threads face the  counterweight.

ASSEMBLY

Three ‘joining’ pieces loosely pre-assembled.

 

1. The concealed brass piece with threads facing the counterweight passes thru the chrome plated metal collet.
2. The rubber washer beveled face presses into the collet and onto the 5mm diameter shaft of the brass piece.
3. Thread the counterweight section very snugly onto the brass threads, compressing the beveled washer.
4.  ‘loosely tighten’ the single allen head set screw to retain the counterweight section’s position. Note: the set screw must be ‘below’ the inner tube’s surface to allow the outer tube to pass over it during balancing/tracking weight setup.
5. Insert into the post, tighten two allen head set screws onto the chrome collet

Note: The notches in the chrome collet face the arm post. The notches originally kept the brass piece from spinning when the counterweight is very snugly tightened onto it. IF it now spins for any reason, simply pre-assemble the counterweight ‘outside’ of the post (when able to grip it with a tool), lastly fasten the completed assembly into the post with the two allen head set screws.

 

 

 

from websters: 'audiophile', too smart for their own good. 

I am not a plumber, although I can fix a toilet and change a washer.  However, the black washer in your photo says "1/4S" and across from that marking are the letters "OD".  This suggests to me that that washer is 0.25 inches in Outer Diameter.  It suggested the same to the hardware store guy who agreed with me.  (I printed the photo you posted to be sure of getting it right.) Neither of us had a clue as to the meaning of "S". (This hardware store does not carry the exact "Everbuilt" brand, but they have a wide variety of beveled washers from which to choose.). On the other hand, we have the photo of the Everbuilt container showing the 1/2" OD claim. I chose the correct OD only because I think 1/4" is too small.

Another Example of 'Expectation Bias'

assume, wish it could say, I am an audiophile, so is the hardware store guy!

put your glasses on: across from the marks ’00’ (not ’’OD’) (letters or numerals?)

which in plumber speak is size # 00 which, as I wrote, as the package is labeled, is 1/2" OD which is for a valve for a 1/4" line. See the washers for larger lines: 3/8; 1/2; 5/8; letters ’S’; ’L’; ’M’, a variety of beveled and curved faces.

 

lewm, others 

for others, it would be good to add to this

A. Set Screw Sizes

1. the size designation of the allen key _______? for the single set screw in the counterweight tube. Assuming someone has to buy one. I had one that fit, I don’t know it’s size designation.

2. 1/16" size designation of the allen key for the pair of set screws in the arm post that retain the chrome plated collet. Is there a metric equivalent _____? to 1/16" that fits those set screws? (I presumed they would be metric sizes)

Kit with 30 pieces SAE and Metric, $14.

SAE SET

 

0.028", 0.035", 0.050", 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32". 3/16", 7/32", 1/4", 5/16", 3/8".

 

METRIC SET

 

0.7mm, 0.9mm, 1.3mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 10mm.

 

B. Alternate Photos of the concealed brass piece.

My current one has a rubber shoulder washer covering the flat flange at the end and a 8.5mm diameter rubber shoulder covering the inner brass end. That pushes into the chrome collet’s 8.5mm inner diameter

 

This shows the uncovered end of the brass piece, a bit mis-shapened

Mine came rubber covered, I got lucky. It occurred to me, if the brass is exposed, it could be wrapped (with tape, dental floss, plumber’s teflon tape, ...) to 8.5mm diameter (to both center and isolate it inside the collet) (avoiding metal to metal contact).

Other photos of the OEM part and solutions would be good to gather. I added the one above with my others posted.

 

First, I’m not the least bit angry about this, but why do you seem to be? In fact, I am grateful for your guidance. Especially since only you and I seem to care. What you fail to understand is that the photo on the right showing a bunch of black washers most prominently displays a washer that appears to be 1/4” OD. Whereas the packing shown on the left does clearly state that it contains washers with 1/2” OD. That is why I sought clarification. That was my only point. Anyway I obeyed the package label and bought 1/2” OD.

lewm

I was just having fun, i’m done, never angry. I’m in love with my metal ruler and quite happy with my phone’s camera.

When I joined in 2019, several others seemed to want to solve this problem for these tonearm models, which, when fixed, is superb, I like it equally with my prior favorite Acos Lustre GST-801. I put it in place of my 12.5" arm, effective length 11-1/8", more precise anti-skate while playing, and removable headshell.

I just received the S version/removable headshell version of my 3rd arm, Jelco SA250 that I found in Germany. I need to ease the post hole over 4mm to install it in place of the Mission 774 which is a Jelco 250ST (210mm S/P distance)

Please add any answers/photos when you take yours apart and discover the condition of the inner brass piece.

That leaves me with 2 spare arms.

I acquired my UA7 series tonearm as a piece of a QL10 ensemble, which I bought only to get my hands on the TT101 chassis. After I much modified the QL10 plinth and finally fixed my TT101, I am using it for my Koetsu Urushi.  The very high mass Fidelity Research FR64S with Ortofon LH9000 headshell and B60 base seemed more appropriate for mounting the Koetsu, and I have been very pleased with the results while the UA tonearm sits idle with its counterweight at half mast.  However, by examination, I agree it is a very nicely made tonearm, superior in many ways in terms of quality of construction to some of the high end most costly tonearms we have today. It is well worth repairing.  What do you suppose is its effective mass, assuming a run of the mill headshell of about 10g? Unsubstantiated rumor has it being medium to low mass.

I found an undocumented post about 7045 being effective mass of 14g

(IF add 19% for 7082’s 37mm longer s/p distance/longer tube = 16.7g)

"Re: UA-7045 effective mass

Post by sebar65 » 13 Dec 2021

Hi, I read that the UA 7045 tonearm has an effective mass of 14 g. I don’t succeed to find the source of this information, but I am sure that this tonearm is adapted to any middle compliance cartridge.
Cheers seb."

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VinylEngine and JVC Victor Literature show a very large cartridge/headshell weight range of 12-32g. Victor specifically mentions low mass/high compliance cartridges in their 7045/7082 brochure.

"Specifications

Type: statically balanced arm with new gimbal support for tracing hold system

Length: 350mm

Effective length: 245mm

Overhang: 15mm

Tracking force: 0-3g (0.1g steps)

Cartridge weight: 12-32g (including headshell weight)

Arm elevation range: 40-60mm

Weight: 610g

Accessories: oil damped arm lifter, low capacitance signal cable"

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my collection’s weights

loose cartridges

5.5g: Grado ME+ Mono Cartridge

6g: shure 44e MM; stanton 600 MM; P mount standard (P mount cartridges track at 1.25g)

7g: shure V15 V-P MM, (6g P Mount in a 1/2" adapter weighing 1 gram) (no brush)

8g: AT14Sa MM Shibata on Tapered Aluminum;

8.3g: AT160ML MM, MicroLine on Beryllium

headshells (AA indicates headshell includes azimuth adjustment)

9g: no name lightweight

13g: Victor, came with 7082

headshells with cartridges (AA indicates headshell includes azimuth adjustment)

15g: Sumiko Talisman S, MC Van Den Hul Line Contact on Sapphire Tube;

18g: Shure V15VxMR MM, Jico SAS on Boron 

18g: AT33PTG/II MONO MC in Pat’s AA headshell (rebuilt MicroLinear on Boron by VAS)

18g: AT160ML MM, MicroLine on Beryllium in AT AA Headshell

19g: Shure 97xe MM in Lustre AA Headshell (rebuilt MicroLinear on Boron by VAS)

23g: AT33PTG/II Stereo MC, MicroLinear on tapered Boron

note: two have weights added onto the headshell for use of a light cartridge/headshell combo in a short arm.

 

 

 

from Ortofon: either length 7045 or 7082 is considered MODERATE MASS Arm

There are a few general "rules of thumb" that we need to consider:

* A tonearm whose effective mass is rated at 10 grams or below is considered low mass (e.g. early SME’s, Grace 747 etc.).

A tonearm whose effective mass is rated between 11 and 25 grams is considered moderate mass (e.g. SME 309, IV, IV-Vi, V, Triplanar, Graham).

Arms above 25 grams of mass are high mass in nature (Eminent Technology, Dynavector).

* A phono cartridge whose compliance is rated at 12 x l0ˉ6 or below, is considered low compliance.

A cartridge whose compliance is rated between 13 x l0ˉ6 and 25 x l0ˉ6 is considered high to very high.

Note: Another way of expressing compliance is um/mN. Here a rating of

5 to 10 is considered very low,

10 to 20 is moderate and

above 35 is very high.