$3K Dex! What Do You Get For The Money?

A client brought in a couple of Dex he had just purchased from a reputable Ebay seller. This seller’s product looks awesome, has all the fruit and are very well presented. By the time you get them freighted you’re up for AU$3000.

I was looking forward to seeing these dex as I’ve followed modding and customisation since day one and have “watched” many of the Ebay seller’s dex in awe.

3kdex-top03Bet they’re amazing right? Everything perfect, smooth, setup supreme, those halo and pitch LEDS blinking away in any colour of your choice with the touch of a remote… Well for the first 30 minutes or so they were great…

Uh oh, I can see where this is going.

On the bench and slip off the under-platter cover to check out the electronics and stare in shock!

OK… WAIT WAIT, give them a chance and let’s not be negative so early on..

OK OK. The presentation is really nice, the dex are powder-coated which is actually pretty expensive here in Australia for small runs, the tonearms look sensational and the platter is really well finished (I’ve rubbed out the sellers logo on the platters which is why the smudge is there). I don’t like the halo and pitch LEDs but who cares what I like. Kudos for the aesthetics of these units.
3kdex-top02
Sweet looking eh?

OY!! Back under the hood. Why were you shocked?

Whooa.. I’ll get to that. Relax.

So beginning the downside slope.

They are SL1210MK2 built in January 1986. They still have SL1200MK2 pitch controls! Yes the ones with the centre click and the frigging “zeropitch” that grabs a slightly out of spec pitch circuit and fucks with your beat.. why would anyone want that in ANY SL1200? Even Technics realised how crap that was in 1997 with the MK3D. I’ve been removing the damn “green light horror” for years. Bad form for the money!

The tonearms were binding. Both tonearms pan bearings had been damaged and slipped into a groove when you tried to balance them. Both had the pan bearing locking adjustment screws loose and needed setting into place. A touch of clear nail polish fixes that if you decide to screw with them in the first place. Bad form for the money!

Those shitty damn transfers where the Technics model insignia used to be. Why can’t someone make a Letraset style transfer so you can embed the words only, not a damn big plastic transfer! YUK. Personal choice I guess.

One of the dex’ platters didn’t turn freely because the halo LED strip’s sticky backing had failed and the LED strip was binding the platter’s rotation. Good glues are cheap these day! Bad form for the money!

The remote control for the Halo LEDs uses an infrared receiver diode device that was supposed to be strategically positioned in a hole in the plastic under-platter cover, so the holes in the platter could be aligned and used to control the colours and patterns etc BUT in BOTH dex they had fallen inside because the receiver diode was only held in with some insulation tape.. you know that self-amalgamating shit that really only sticks to itself… So neither remote worked out of the box. ho hum. Bad form for the money!

Phew, so can I ask why were you shocked first up?

OK, This shit makes me angry. Clearly these were put together by someone with little knowledge of electrical safety or understanding of electrical standards in Australia (or the world for that matter). These units were a potential hazard and could have caused damage to gear or serious injury to anyone touching them.

Look at this image of the internal electronics of these dex…
3kdex-smps
That black mass of cheap insulation tape (not again) is holding a small SMPS to supply the halo and pitch control LEDs. An SMPS is a switch-mode power supply. It takes 100 – 240V AC and chops it up to the desired output voltage, in this case 12V DC. The primary side of an SMPS is dangerous as it is “live” and needs special consideration in regard mounting and insulation.

A Technics SL1200 (as is most DJ equipment) is a Class II Electrical Appliance meaning it does not require a hardwired connection to electrical earth (ground) because each potentially dangerous component is (by law) required to have two or more layers of insulation. The result being, no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock. If the primary side of this SMPS was to come into contact with the dex chassis the only return path is through the user or the audio ground and back through the mixer.. which ever is lest resistance… both options ugly.

The SMPS in the image above is just wrapped in insulation tape and left resting in the bottom of the turntable. The plastic platter-cover just touches it enough to “hold” it in place by applying a small amount of downwards pressure. The components in the primary of the SMPS have sharp leads which with little effort can push through the pathetic plastic insulation with ease.. you can see what’s going to happen eventually can’t you?

I don’t know the moral of this story. I don’t want to seem an asshole but at the same time I feel this is a potential serious risk. The risk of injury, death and fire is present. If you are importing gear from overseas, I highly recommend having it checked by a qualified electronics repairer or engineer.

Wow! I feel your concern. I am curious though, why did these dex come to you in the first place?

Yeah I never said did I?

They had both blown a fuse. My head will not let a blown fuse go. They always blow for a reason which is why I looked deeper. I added extra insulation in the form of cardboard sheet and cloth tape to the bottom of those SMPS boards so I hope I’ve reduced any risk.

I think they blew fuses because of Western Australian power reaching 255V on occasions which will saturate the cores of iron transformers with flux and cause massive inrush currents and destroy the fuses. SL1200 use a 250mA fuse which is just too small for WA 🙂

Thanks for reading. If you got this far the secret word is LudlamFTW.

Asshat Turntable Repairs!

<rant>

OK.. I’m angry!

Six times in the last few weeks I have received SL12xx dex that have had tonearms replaced by some hack asshat who needs to be removed from touching anything more complicated than a Maglite!

I am pretty sure I know who it is.

This asshat is replacing tonearms but not feeding the wires correctly. The result is they work fine for 1 – 3 months and then start shorting to the chassis intermittently. From what I have ascertained this person blames the DJs for doing something wrong when one channel drops out randomly.. this shit really gets my goat and this industry is rife with clowns who think they are fracking experts..

Downside is the owner/venue is paying for a shit job AND worse it is depleting the remaining stock of Technic’s spare parts because this twat big notes himself as a “repairer”.

I really need to start a Perth shame file. Some of the crap “repairers” are getting away with is fraud IMHO.

Here’s an image of the work this assclown is doing. Clearly the wires are trapped and a drama waiting to happen.

IMG_2302
I can’t believe I didn’t fucking swear in this post!

</rant>

Design Your Next Dex

.. so I have a stripped pair of SL1200MK2 ready to customise. Here’s your chance to give me a colour scheme.

Let me know what body colour, tone arm colour, pitch control scale colour, LED colour, platter colour… best one gets first dibs 🙂

oh and I’ll post the progress as we go.. could we have more fun?

Here’s your canvas…

IMG_2530

 

That’s Gotta Hurt!

Please.. if your going to transport your dex around the world, make sure you pack them in a touring roadcase or at least protect the tonearm area and ensure the platter isn’t going to go AWOL.

A pair of SL1210MK3D arrived today with broken tonearms. One off them had actually broken the cast frame. I have never seen the assembly snap in this way before. This has had one serious whack on the top..

OUCH

ouch

Please use the contact form to enquire about converting or modifying your SL1200.

SL-AdminStay locked!

It’s an SL1200 Power Struggle

…So since the “export” power transformer has just recently dried up in Japan, I wanted to figure the most economical and electrically sound and safe way to convert 120V AC Technics SL1200 turntables to 240V AC with the least fuss whilst still leaving them double insulated as per the original specification and Government regulations.

TestingI set one up and monitored its current draw under various conditions and the results were interesting. The original transformer provided 32VAC on its secondary at idle BUT as the current demand increased to the maximum the secondary voltage dropped to 27VAC..

Here’s the results for interest’s sake…
Primary Volts = 242VAC – Secondary 32VAC
AC current demand Idling – 350mA
Idling with lamp on – 430mA
Rotating at a constant speed with lamp on – 450mA
Stalling platter with lamp on – 955mA
Spinning backwards with lamp on – 1030mA
At full peak current demand AC drops to 27VAC

Not really an issue as the DC voltage required is 20V DC BUT I considered the peak current demands the motor circuit required during spin backs and stalling and observed a slight loss of recovery torque due to the poor regulation of the standard power supply compared to my test bench power supply.

Transformer detailI have found a modern toroidal power transformer that not only has a minimal electric field so as not to interfere with the close proximity of the motor circuit’s feedback windings but gave a slightly quicker recovery time as a power supply.

Ultimately I can convert export SL1200 to 240VAC and make them have better recovery from stalled at a very reasonable price and they look good.

Word!

[UPDATE] We have developed a non-intrusive replacement part for these now so please take a look here
TECHNICS SL1200MK2-6 Power Transformer Assy

Please use the contact form to enquire about converting or modifying your SL1200.

SL-AdminStay locked!