Problem with AR-Xa Cartridge Shell

[nnicola]

I recently purchased an AR-Xa turntable and I'm having a problem separating the cartridge shell from the tonearm. I've unscrewed the shell but can't get it off the tonearm. I don't want to apply to much force for fear of damaging the shell or the tonearm.

Has anyone encountered a similar problem with this turntable?

Any ideas?

Thanks.

 

[Calypte]

You've probably already done this, but you do have to make sure the collett is completely off the threads, so that the collett is loose on the arm. The headshell might still require a bit of twisting. Unfortunately, it's this maneuver that damages the delrin bearings in the hub of the arm, unless you somehow hold the arm very securely in one hand. One thing that has helped me is replacing the stock armrest with one that has a clasp, and keeping the arm locked in the armrest while you remove the headshell.

 

[marcmorin]

Sometimes, due to the nubs on the headshell wearing out, people glued the headshell into the socket...............I see all kinds of "bright ideas" on tables i get.

 

[nnicola]

Sometimes, due to the nubs on the headshell wearing out, people glued the headshell into the socket...............I see all kinds of "bright ideas" on tables i get.

Yeah, that thought had crossed my mind. Worst case scenario is that I'm stuck with this for the short term and will have to work around the problem. I imagine that I can probably install a new cartridge with the shell stuck to the tonearm. It will be more difficult, but not impossible.

Thanks.

 

[nnicola]

I was finally able to separate the shell from the tonearm using nothing more than muscle and was lucky that I didn't damage anything. I installed a Shure M97xE cartridge and all seems to be working well. The tonearm wiring seems to be intact without any hum. The replacement belt arrived today and the platter is spinning at 33.2 rpm's without any discernible wow and flutter, pretty amazing for a 56 year old turntable!

 

[marcmorin]

I was finally able to separate the shell from the tonearm using nothing more than muscle and was lucky that I didn't damage anything. I installed a Shure M97xE cartridge and all seems to be working well. The tonearm wiring seems to be intact without any hum. The replacement belt arrived today and the platter is spinning at 33.2 rpm's without any discernible wow and flutter, pretty amazing for a 56 year old turntable!

measure the width of the belt, should not exceed 0.135 - 0.140" , wider than that, and it will run slow. original was 0.125" but those days are gone.

 

[nnicola]

measure the width of the belt, should not exceed 0.135 - 0.140" , wider than that, and it will run slow. original was 0.125" but those days are gone.

Marc, I'm currently using a Shure M97xE cartridge with the turntable. I have seen some instructions from AR that standoffs should be used with some Shure cartridges, and in some cases a shim should be placed toward the front of the cartridge to angle it slightly.

Do you have a recommendation on this, or can you point me towards more detailed information on correct cartridge alignment?

Thanks.

 

[marcmorin]

Marc, I'm currently using a Shure M97xE cartridge with the turntable. I have seen some instructions from AR that standoffs should be used with some Shure cartridges, and in some cases a shim should be placed toward the front of the cartridge to angle it slightly.

Do you have a recommendation on this, or can you point me towards more detailed information on correct cartridge alignment?

Thanks.

all that paperwork from AR on this was written well before the M97xE was made. setting SRA/VTA will have to be done by eyeball. platter mat thickness comes into play, album thickness comes into play. getting it "perfect" ain't gonna happen. getting it close enough for gub'ment work is easy enough though.

 

[nnicola]

all that paperwork from AR on this was written well before the M97xE was made. setting SRA/VTA will have to be done by eyeball. platter mat thickness comes into play, album thickness comes into play. getting it "perfect" ain't gonna happen. getting it close enough for gub'ment work is easy enough though.

Marc, I've started to detect a low frequency hum with the volume turned up. Not really noticeable at low volume levels. Time for a tonearm rewire? If I touch the tonearm or shell the hum gets just slightly louder.

 

[marcmorin]

Marc, I've started to detect a low frequency hum with the volume turned up. Not really noticeable at low volume levels. Time for a tonearm rewire? If I touch the tonearm or shell the hum gets just slightly louder.

you have a bad ground somewhere. do you have a digital VOM? If the arm has original wiring, the majority of time in bad grounding is the metal screen around the arm wires is broken in the area that passes through the top plate

 

[nnicola]

you have a bad ground somewhere. do you have a digital VOM? If the arm has original wiring, the majority of time in bad grounding is the metal screen around the arm wires is broken in the area that passes through the top plate

I have an analog Multimeter, not a digital. Will that make a difference? (I am a relative newcomer to this and do not have much experience.) I believe it is the original wiring. If it is a bad grounding because of a frayed metal wrap, is rewiring the entire tonearm a fix? Won't rewiring need to be done eventually, or am I jumping the gun?

 

[sfrost]

Very hard to fix the braided ground wire, can try to run an extra wire for ground but I usually recommend rewiring the arm because it may need it eventually anyway. Any meter will would for checking continuity.

 

[marcmorin]

As Sfrost noted, if you find the bad ground area, the rewire is generally in order. This could be to poor connections of the headshell pins, headshell wires, they have a tendency to get a black oxide build up where they attach to the cart. Which is why i suggest checking the arm grounds as many places as you can, and then across both pins of the RCAs to make sure you have close readings from both sides of the cart at the RCA ends. This is where a DVOM is a bit safer than an analog meter

 

[cre009]

Marc - With the stock wiring my understanding is the braid formed by the ground from the arm pivot effectively acts as a screening shield. Is there any technique for achieving this with new replacement wires such as with Litz twisted pairs?

 

[marcmorin]

Marc - With the stock wiring my understanding is the braid formed by the ground from the arm pivot effectively acts as a screening shield. Is there any technique for achieving this with new replacement wires such as with Litz twisted pairs?

twist the channel pairs, braid the ground wire to those pairs.

 

[cre009]

twist the channel pairs, braid the ground wire to those pairs.

ok - thanks - I assume the braiding should be quite close knit to be effective but there must be a balance between getting things over stiff and interfering with the arm movement. I don't believe I have seen any example pics to know what to aim for.

 

[johnjhazel]

Sometimes, due to the nubs on the headshell wearing out, people glued the headshell into the socket...............I see all kinds of "bright ideas" on tables i get.

I briefly owned an AR XB where some genius applied Loctite to the vertical tonearm bearing screws.

 

[marcmorin]

I briefly owned an AR XB where some genius applied Loctite to the vertical tonearm bearing screws.

I add superglue, but only after i've rebuilt/modified the vertical pivot assembly. But, i see it often too in my rebuilds. generally putting the pivot block in the oven at 300-325 for half hour softens the stuff up.

 

[johnjhazel]

I add superglue, but only after i've rebuilt/modified the vertical pivot assembly. But, i see it often too in my rebuilds. generally putting the pivot block in the oven at 300-325 for half hour softens the stuff up.

The person had the bearings or one of the bearing too tight when he glued it. I was able to seemingly set the tracking force. But, it would skip often. I used my Shure balance beam scale to check of course. When the scale beam was level, I blew on the headshell. The beam bottomed out and did not come back to level indicating too much vertical bearing resistance. I used that test to adjust the tonearm on my current AR 77-XB. Seems to work great for adjusting the bearings to get just the right amount of bearing play without slop.

 

[marcmorin]

The person had the bearings or one of the bearing too tight when he glued it. I was able to seemingly set the tracking force. But, it would skip often. I used my Shure balance beam scale to check of course. When the scale beam was level, I blew on the headshell. The beam bottomed out and did not come back to level indicating too much vertical bearing resistance. I used that test to adjust the tonearm on my current AR 77-XB. Seems to work great for adjusting the bearings to get just the right amount of bearing play without slop.

my vertical bearings are sapphire, and micro polished pins. Don't want nobody trying to "adjust" them, hence the super glue