$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.
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…
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.

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