Too Funky Mitsubishi LT-640 Linear

[visman]

OK - could not pass up on this near mint MGA/Mitsubishi "Integrated Logic Controlled Linear Tracking Turntable" at the local thrift store.

Is this the funkiest table or what?

Not sure on the cartridge - stylus is marked 3D-47M. I did manage to break off the leads while removing the cartridge so that will be a project. Also needs a new belt - but hey I am pretty sure this this one is for show not play.

Check out the cool record clamp.

Here are some shots.

 

[RickB]

I've got to find my old 1984 Audio Buyer's Guide, they had a report and test of the vertical Mitsubishi table...seems like they splooged all over themselves about how playing records in the vertical plane kept all kinds of nasties from coming through the system....they really liked the deck....

 

[Balifly]

There was a similar one made by Sony at a local YWCA auction a few months ago. :drool: My bid was put in with faint hope and little expectation. :yes:

 

[visman]

RickB - that would be very interesting.

Well I couldn't help myself and opened her up - large cover on the back opens to reveal virtually everything.

Replaced the large belt (had one that fit pretty good) - both other small belts (arm drive and lift drive) both where in good shape.

turned the power on and hit play - everything worked good platter spins even the little light shinning on the record worked :yes:- arm lifted from the rest went all the way to the end of the record then back to the rest set itself down and shut off.:scratch2:

This will require some thought and a service manual!

 

[sloober]

I love linear, and that sure is funky! I dig it. John

 

[deaner33]

Those tables weren't cheap junk. Great score!

 

[julian_photo]

well its an interesting idea really. If we don't want dust to land as we are playing stuff why not make so there is nothing to land on. Hope you get this one working

 

[cbrworm]

I had the LT-10V - very similar.

If the arm goes all the way to the end and back it usually meant that one of the light bulbs was burned out. It used lights and optical sensors/interupters to detect record size and arm angle. In mine I replaced the incandescent bulbs with green LED's and they never burned out again.

I don't know if yours is the same, but look for small incandescent bulbs in the mechanism that might be burned out. Two were in the crossbar shining onto the record to detect the size and two were on the back of the mechanism (inside) to detect the arm position.

 

[cfranz]

My lt-20 was one fine piece of equipment, until an IC cooked... Couldn't find a replacement anywere... good luck on yours, they are really good TTs

 

[visman]

cbrworm - thanks for the advice. That does make sense as everything else seems to work great.

I will check it out - i'll take some pictures of the inside it's pretty cool too.

 

[visman]

Well - as it turns out there appears to be only one lamp for identifying record size - and it is working - the two receptor reflectors are built into the table mat. I removed the light receptor box inside the turntable and tried jumping the record size pins - but to no avail. The tonearm continues to lift go to the end of the record and then return to the rest and set down.

I wonder if anyone might have a user manual for the LT-640 as it has now officially become a project.

 

[BrocLuno]

Good project - hope you get it sorted out

 

[tuffgong]

i have this same turn table... does your have a ground wire?

 

[Balifly]

I have a Mitsubishi Lt-20 an was able to download a owners manual from http://www.vinylengine.com/library/mitsubishi.shtml.

I know that they are not the same, but there are similarities.

Hope this may help you in getting your turntable to perform to your satisfaction.

 

[Vintageman1]

I still own my LT 5V (see Avatar). Still works but has a speed control problem. 331/3 cannot be set but 45 can. Deoxit on pot had no effect. Love to get it working as I have hardly used it the last 5 years and my wife won't let me sell it.

 

[Eazy E]

Well - as it turns out there appears to be only one lamp for identifying record size - and it is working - the two receptor reflectors are built into the table mat. I removed the light receptor box inside the turntable and tried jumping the record size pins - but to no avail. The tonearm continues to lift go to the end of the record and then return to the rest and set down.

I wonder if anyone might have a user manual for the LT-640 as it has now officially become a project.

Vinylengine has a schematic of the MC-8000 (http://www.vinylengine.com/library/mitsubishi/mc-8000.shtml) which looks like it has the same deck in it.

I had a similar problem with my turntable (in the Mitsubishi x-10 'vertical music centre' - I believe it's the same set-up). There are three small bulbs/LEDs on a small circuit board on top of the tone-arm assembly. The closest to the back is the 'stop' light, the middle one is the '33 1/3rd' light, and the one closest to the front of the machine is the '45' light.

When you turn on the power, the 'stop' and '33 1/3rd' light should come on by default (the '45' light should come on if you hit play and the deck detects a 7"). If they're not lighting up, they may be burnt out - I had to replace all three. I hadn't done any soldering before, but didn't find it too difficult.

You will see the arm tracks along a metal plate with corresponding grooves cut into it - when for example the '45' light passes over the corresponding groove, the light passes through the plate to a light sensor which tells the arm to drop.

Let us know how you get on,

Cheers, Eric.

 

[koseltri]

I think there is something in what Eric says. If it was the size detection lamps, they would both be covered with an LP in place, so it shouldn't matter if those lamps work. The hole on top originally had a rubber plug in it, so *someone* has been messing with the set-down adjustment (there is an eccentric that moves the slotted metal plate back and forth), probably an attempt to get the tonearm to set down. If you have a 45, try it and see if it sets down properly. I had to replace the '33' lamp in my LT-20, it would play 45's, but 'ignore' 33's. Keep us posted.

 

[Eazy E]

Just attaching a couple of pics to clarify what I was talking about above: the first is a general view of the back; second is the tonearm assembly on its metal plate; third is a closeup of the circuit board in question (showing one of the lamps/LEDs mentioned).

Fourth is my setup

Cheers, Eric.

 

[Montycat]

I think there is something in what Eric says. If it was the size detection lamps, they would both be covered with an LP in place, so it shouldn't matter if those lamps work. The hole on top originally had a rubber plug in it, so *someone* has been messing with the set-down adjustment (there is an eccentric that moves the slotted metal plate back and forth), probably an attempt to get the tonearm to set down. If you have a 45, try it and see if it sets down properly. I had to replace the '33' lamp in my LT-20, it would play 45's, but 'ignore' 33's. Keep us posted.

Old thread I know...

Good tip. I'm working on an Interplay X-10 right now. The arm drive belt was goo, but an elastic band is doing the job right now. A 12" record would not play but a 7" 45 would. :thmbsp:

It would not detect the end and return either, so perhaps an adjustment or another sensor.

 

[Sarah Lister]

I know this is a long shot as this is a pretty old thread ... How did your project work out in the long run. I'm having a the same issue. I can't wrap my head around it.