Technics Mismatch

[Qwin]

I’ve been putting together a test bed for my experiments in adapting a platter from another deck to fit and work with the Technics motor assembly like so:

http://www.jkwynn.co.uk/Project_Images/Platter/Platter_009.jpg

I’ve hit a bit of a snag, the PCB I purchased off fleabay is a late variant of a Mk5G and the control buttons are off a mk2. You guessed it the plug on the switch harness is incompatible with the socket on the board.

Anyone got any suggestions how to get around this?

Are the mk5G plugs available and does anyone have a source?

I could just remove the connectors and solder the leads direct to the board but it’s not pretty.

I cold also remove the individual receptacles from the harness plug and slide them individually on to the pins of the socket on the board, without the housing. Again not ideal and without the latching body of the plug it would be easy to pull the leads out.

If anyone has come across this problem I would be interested in how they got round it as it’s the only thing stopping me from trying a powered trial with the new platter installed.

:please:

Thinking about it, I had better check the pin outs are the same for the two variants before hooking anything up, again any knowledge on the subject would be appreciated.

[6L6]

What is it, 4 wires? Cut the plug and solder.

[DarrenHW]

Could you not rig up an adaptor harness (similar to those used to fit after market head units in cars) between the 2? Is that the Project bearing / spindle??

[Qwin]

Darren - I don't have plugs and sockets to make an adaptor. If I did have some I would just solder the correct plug on my harness and would not need an adaptor.
That is the Pro-Ject spindle mounted in the centre of the motor. The magnet and detection hub are mounted on the Pro-Ject Platter which has the bush/thrust bearings mounted in it. It works the oposite way to the Technics, kind of updide down. I have done a trial fit and it rotates freely without contacting the coils.

Jim - Yeh five wires and I am tempted to solder them. I don't like the Idea of soldering to the pins on the header attched to the Board though.
Trouble is removing the header can be tricky as these boards seem to looze the tracks/pads easily. When I removed the rectifiers on my two boards, the same ground solder pad lifted off durring removal. I had taken great care in trying to make the process as quick as possible to reduce the heat getting to the tracks/pads bit it still happened. I cut through the legs of the rectifier and pulled individual legs through from the top face so heat was applied for only 3 seconds and the solder pad still lifted so I am cautious about that approach.

The switch block I am using for these tests is borrowed off another deck so I don't want to hack it up as it will be returning to duty at some point. The external PSU/switches off my main concrete deck will eventually power this unit but as it is going to take me a few months to sort this design and build a new concrete plinth for it. I don't wan't to be without music for that long. I quess its just me, skin flint that I am, trying to juggle with just the parts I have. I should really source another switch assembly and just solder it to the header pins as a temp measure. Brain wave - I will just remove the recepticles from my plug and slide them on to the individual header pins. I had forgoten that this is just a temporary arangement to prove the platter/motor work together. I will be able to restore the plug to its original state when finished.

Ah well, at least typing this has made me think out loud and find a workable solution.:D

I am posting my progress on my web site but will post the whole thing hear when/if I am successful.

[Frankyc2003]

:popcorn::popcorn::popcorn::popcorn:

Surely this is the genesis to a Super deck if there is one!

[DarrenHW]

I don't know what they're called (no surprise!) but what about using the wires that connect the Cartridge to the Bayonet on the stock arm. They need a little bit of squashing to get a snug fit but slip on quite nicely, a piece of heat shrink or something similar could be used as an insulator. To create the male end dare I say it, but you could use something like a paper clip. Not trying to teach you how to suck eggs!

http://i1324.photobucket.com/albums/u606/drtwas/IMG_3385_zps6e4cb949.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_3385_zps6e4cb949.jpg.html)

[Qwin]

Darren - I've sorted it. It's like you show in your picture but I have used the connectors already fitted to the wires in my Black Housing on the harness. If you use a pin you can release the metal contacts from the plastic housing. I slid these individual receptacles on to the pins like in your photograph and like you say some form of insulation between the pins would be prudent. This is after all a temporary installation to prove the motor assembly. I will solder the final version when I install it in a plinth.

Just as a side issue, I am taking a different approach to other platters. Where other (commercial) people have been limited by the need to be compatible with the standard Techie Plinth and bearing, even if the latter was re engineered, I have not been restricted by this and to some extent had a blank canvas.

I had a tatty Pro-Ject RPM9 deck I picked up cheap, just sitting Idle. I was staring at it one day thinking, that is a cracking platter and bearing set up going to waste.

Marco had commented, I think on the recent and long alternative platters thread, about the motor being the essence of the deck, in reply to "when with all the mods does it cease to be a Technics”. I was reading this, looking at the Pro-Ject platter and thinking what are the chances of these being compatible?

6L6’s DIY power supply and regulator could be used and the rest of the parts can be had second hand off the net, with a custom plinth made to suit, my mind was racing ahead……

This was what set me off, and I think, if you have followed any of my work, you will know I am not shy of trying alternative ways of doing things, mainly to make use of what I already have and within the constraints of my very limited facilities.

keep watching as I’ve nearly completed the PSU and subject to having some cable spare to hook it up, will be trying the motor out electrically in a few days. If it works, and there is no reason why not, there will be a new plinth on the drawing board. :eyebrows:

[Qwin]

Well she works.

http://www.jkwynn.co.uk/Project_Images/Platter/Platter_012.jpg

I removed the receptacles from the connector on the control harness and clipped them direct to the pins on the board. I heat shrinked every alternate connection to prevent them shorting. For the PSU, I couldn't wait for the correct leads and connectors to come through the post so I hard wired it for a trial. It powered up and runs perfect.

The only tweak necessary was to give the brake about a quarter of a turn on the adjuster, this platter is 38mm thick Acrylic and weighs 3.5Kg which is approximately twice that of the stock Technics Platter.

Well that's the drive principle proven, I had better design a deck to put it in. :eyebrows:

[Bacek]

Do you plan any electromagnetic shielding for motor? Original metal platter did it.

[Qwin]

Intersesting point that you raise about shielding but is it needed?

The thin die cast alloy of the original is not the best for shielding and some of the upgrade platters sold are plastic, so I'm wondering if its much of a problem?

There are ways of implementing a shield if necessary.

[Bacek]

As you see Technics transformer is shielded but for my taste motor produces much more electromagnetic noise. Thin or not, grounded metal platter is pretty good electromagnetic shield. Maybe it's not the case,because magnet and its assembly is sounding motor coils but assembly has some holes so some noise can be present in the middle of the platter. But I guess TT is working on really low level signals so it's wort to check.

[Bacek]

Also bottom part of Technics chassis is grounded aluminum so there is no place when em noise form motor can reach needle or signal wires (except small two holes in plater itself). You could use sheet of aluminum foil or copper paint on platter bottom and ground it to spindle

[chris@panteg]

I believe the circular magnet's magnetic field is only on the inside, you can easily test this with a screwdriver , taking great care of course.

[YNWaN]

The majority of the magnetic field may well be directed inward but there will still be some leakage - how much of an issue that is is another matter.

[chris@panteg]

Yes, and I guess a plastic type platter will offer no screening against this.

[Qwin]

Just to note guys an Aluminium alloy platter presents zero shielding for a magnet.
There are different forms of sheilding used for EMI, RFI etc.

If you do not believe me try putting a magnet one side of the Techie platter and a hold a steel screw on the other, the screw will literally leap out of your fingers towards the platter.

I think YNWaN's point about how important this is may be most relevant, after all, Mike News ETP (plastic) platter seems to work just fine and that is thinner than the one I have used, so maybe we are looking for problems that are not there.