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Mitsubishi LT-30 restoration

JohnVF said:
But there's just something about the V-15vmr that I really really like. I've had an AT-150mlx on this table but I don't really care for that cart. It's not that I necessarily prefer the LT-30 to the Classic, its rather a case of the 30/V-15 combo being more about the music and less about me trying to eek every last bit of detail and resolution out of the system- and the system that the VPI is in (Klyne preamp/levinson amp) is more along those lines.


John, I have a LT-30 with the same cart. and a LT5-V with a Shure M-91 EM on it. The 91 sounds pretty good but when I switch headshells between the TT's whichever has the Vmr on it is the clear winner sonically.
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Pio1980 said:
I've decided to remove and disassemble the arm carriage and now have the tracking shuttle light gate exposed and ready for a lamp replacement. This has given me the opportunity to clean and lube the tracking rollers and the rest of the lift mechanism and motor. Not difficult so far but time consuming so I'm hopefully making it a one-time procedure. As every other person that has preceded me has discovered, these things are exceptionally well-built.
The last choice to be made before reassembly is whether to go with drastically shortening the existing internal signal wiring or replace it entirely.
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Sounds like great progress, Steve. Post pics if you can.
 
Yes. but--

Aerobat said:
Sounds like great progress, Steve. Post pics if you can.
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I have encountered a wierd problem, checking arm leads before re-installation
shows a consistent ca 750^ resistance in the white left channel arm run absent from the right side. I've definitely established it's somewhere in the arm, consistently steady to wiggling the headshell contact, bi-directionally linear to a diode check, and otherwise of unknown origin. Show has stopped to try to figure this out, I am stumped.

BTW, Should have taken pix of the tracking shuttle gate, too late now.
EDIT: done here; (http://www.audiokarma.org/forums/showpost.php?p=5294896&postcount=153) .
The hum problem others have encountered may be due to not dressing the arm signal wiring to the muting board separate from the other wires. I'll see when I can get this one back together and working.
 
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Pio1980 said:
I have encountered a wierd problem, checking arm leads before re-installation
shows a consistent ca 750^ resistance in the white left channel arm run absent from the right side. I've definitely established it's somewhere in the arm, consistent to wiggling the headshell contact, bi-directionally linear to a diode check, and otherwise of unknown origin. Show has stopped to try to figure this out, I am stumped.

BTW, Should have taken pix of the tracking shuttle gate, too late now.
The hum problem others have encountered may be due to not dressing the arm signal wiring to the muting board separate from the other wires. I'll see wein I can get this one back together and working.
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Sounds like you may have to pull the arm wiring. Good time to replace it with Cardas...
 
I have never rewired an arm pipe and am quite apprehensive about attempting doing it not knowing what works and what doesn't, leaving a useless arm tube. This pipe reportedly has internal Butyl damping and I dunno if the pipe is stuffed tight enuff to make replacing the wire difficult. There is very little margin re wiring free length on the base end and withdrawing the socket to check the base end needs at least 3/4" or more to clear the pipe and will probably pull the wiring ends into the pillar post.
I'm thinking this one thru long and hard, asking for any experienced assistance.
 
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Hi Steve, I've done a few and it's not that bad. Securely tie a good long piece of fine fishing line to the ends of the wires under the tonearm base. Loosen the collar and pull it away from the arm tube. You should be able to get an idea whether the wires are free inside the tube. If so, you can pull them out along with the line.

Next solder the new wires to the collar. Tie the line to the new wires and pull back through to the base. Watch for a ground wire that's soldered inside somewhere and be gentle with it.
 
The arm ground wire is probably entangled with the signal wires and will have to come with the others if something like that will work assuming it's attached somewhere to the socket assembly, that will be a major complication in any case as Cardas does not supply the ground run with the kit. Given the likely small size of the passage thru the gimbal block I think another wire will have to be soldered to the ends as a pull-thru snake rather than using a knotted fishing line.
 
A guy with the nick Eisekiel (AKA Randy Young) sold an LT-30 with the rewired tonearm at Audiogon last year. You could try to contact him.

Pio1980 said:
I have never rewired an arm pipe and am quite apprehensive about attempting doing it not knowing what works and what doesn't, leaving a useless arm tube. This pipe reportedly has internal Butyl damping and I dunno if the pipe is stuffed tight enuff to make replacing the wire difficult. There is very little margin re wiring free length on the base end and withdrawing the socket to check the base end needs at least 3/4" or more to clear the pipe and will probably pull the wiring ends into the pillar post.
I'm thinking this one thru long and hard, asking for any experienced assistance.
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As it turns out I'm a member of Audiogon due to the botched LT-30 sale last year and have sent Ezekiel an e-mail thru A'gon. Thnx for the heads-up!
Rehearsing several possible alternative procedures in my head, I like using a doubled loop of waxed dental floss pulled thru with all 5 wires and replacing the signal runs with Cardas and reusing the ground wire, all pulled back thru with the floss. I'll try disassembling the headshell socket from the arm soon and see what I have to work with.

Edit: ended up pulling the floss loop thru with a single signal wire after removing the arm in it's gimbal frame from the base, makes it much easier IMO.
More good stuff follows-----.
 
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Please make pictures of all re-wiring stages such as how you made these double loops and how you attached them to wires etc etc. Future generations of LT-30 lovers will erect you a monument!:yes::yes::yes:

Pio1980 said:
As it turns out I'm a member of Audiogon due to the botched LT-30 sale last year and have sent Ezekiel an e-mail thru A'gon. Thnx for the heads-up!
Rehearsing several possible alternative procedures in my head I like using a doubled loop of waxed dental floss pulled thru with all 5 wires and replacing the signal runs with Cardas and reusing the ground wire, all pulled back thru with the floss. I'll try disassembling the headshell socket from the arm soon and see what I have to work with.
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I owe you and others a debt of gratitude for the documented ground you've covered and shared with the class and will try to pay it back and forward with any useful contribution I can make.
 
I suspect the resistance problem with the left channel is probably long-term if not factory originated (likely) and went unnoticed as the non-directionally linear series insertion loss of 750^ would have been insignificant and unnoticeable along with the lack of diode-effect distortion due to it's high ratio to typical 47k loading of MM/MI/HOMC carts. Had a LOMC been used with SUT or active 100^ loading typical for these carts a significant channel imbalance and severely low left channel output level would have been obvious.
 
I don't think I have this problem on mine since LOMC carts didn't give significant channel imbalance. OTOH, who knows- I'll check the resistance of tonearm leads with DMM.

Pio1980 said:
I suspect the resistance problem with the left channel is probably long-term if not factory originated (likely) and went unnoticed as the non-directionally linear series insertion loss of 750^ would have been insignificant and unnoticeable along with the lack of diode-effect distortion due to it's high ratio to typical 47k loading of MM/MI/HOMC carts. Had a LOMC been used with SUT or active 100^ loading typical for these carts a significant channel imbalance and severely low left channel output level would have been obvious.
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I think this problem is unique to this example.
Tried pulling the socket and encountered stalling consistent with pinched wires, green wire eventually broke apart somewhere in the arm and could not be withdrawn leaving only the red wire available to use as the pull snake as the white and blue pulled in too far to retrieve. Removed the Butyl arm damper plug to clear the tube and still found the green wire firmly clamped somewhere. Further disassembly found the green clamped between the gimbal frame and the upper basemount.
I used the remaining red wire to pull one doubled loop of waxed floss pulled thru the arm tube and gimbal, then separated, to pull each pair of arm wire back thru rear-to-front taking particular care to not disturb the black ground wire which would be major trouble if pulled free. Next will be to reconnect the socket pins and replace the damping plug before replacing the socket , then reassemble the arm base and carriage.
Took lotsa pix, will follow up later.
 
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Go Steve! It looks like this table will be better then new once you're done. What do you plan to do about the plinth damage?
 
Arm/Carriage reassembled and resistance checks are as expected. Next to reassemble into the baseplate. I'm debating pulling the spindle motor and lubing it on the way out.
Regarding the plinth damage, it's actually relatively minor cosmetics. I'd like to figure out a wood-glue corner press arrangement to reset the bunged portions and use wood furniture die pens to blend coloring differences. I've ordered some soft older style VCR covers cheap to see if they fit it as dust covers.
 
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Be careful not to pinch wires when reattaching the PC board holder. Don't ask me how I know...
 
Aerobat said:
Be careful not to pinch wires when reattaching the PC board holder. Don't ask me how I know...
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Not sure which PC board holder you mean, managed to pinch the cart sig wires under the selector track detector remounting it to the carriage, all good now.
I'm trying to do more "fixing" and not too much damage in the meantime, hoping to come out 'in the black'.
 
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Got it all back together this a'noon and all functions are A-OK. :banana::banana::banana:
Put the Denon DL-110 in the composite shell in it and set it up by ear. Holy ####!!!, does this thing ever sound good!! I'm playing it thru the $38 e-Bay Audiowind phono right now, still need to order board parts for the CNC.
Pix to follow.
 
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