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NEKID PICHURES!! (Roland RD-700NX)

Posted By: dewster

NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 12:40 AM

NSFW! - You must be 18 or older to view this thread! - NSFW!

"What're you up to?" my wife asks as she glances up and sees me carrying the keyboard downstairs to the den. When I tell her my intentions she says "you mean our brand new $2100 keyboard?" By now she's used to this kind of behavior and her brief half-hearted protest is mostly just kidding, though I detect a bit of worry mixed in. "It's way past the lame 90 warranty period" I say "so if anything goes wrong with it I may as well get a preview of what I'll be up against" which sounds surprisingly semi-plausible even in my ears. Honestly, I always have a bit of self-doubt when attempting these things, you never really know what fastening horrors may be in store.

So anyway, I laid the RD-700NX out on the futon couch, ran my fingers over its keys, and slipped off its case. Then grabbed the camera and did a naked photo shoot - Woot! Let's all take a gander at them gams...

[Linked Image]
To get inside, I set the keyboard with it's very back on the seat of the sofa, and let it gently lean back with the controls and keys against the back of the sofa. This allowed access to the underside without putting undue stress on the protruding topside controls. The screws to remove are the 7 along the back side, the three on the left, and the three on the right (all yellow arrows) which are the self-tapping variety. The final screw to remove is the second one in from the left (front metal tab, red arrow) which has machine screw threads. Then rotate the DP down on it's bottom, and flip the top back, being super careful not to stress the rather short ribbon cables connecting the two major halves. Note the futon cover, still going strong after over 20 years of solid use, kept alive through the perverse power of its sheer hideousness.

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Here is the NX with the top flipped back. That's obviously the keys down front, the small board on the right with the yellow transformer is the AC (switching?) supply, the main "brains" board is in the middle, the rear I/O board is to the left, the joystick at the upper left, and the main control & display boards @ upper center. Note the use of a stuffed animal puppy keeping the top from overextending the connecting cable (it was specifically designed and calibrated for this use).

[Linked Image]

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Left and right views of the main processor board. Chips are as follows:

Code
QTY PART#                     PKG     DESC
1 - ESMT M12L16161A-7T      - TSSOP - 16Mb SDRAM, 2 x 524288 words by 16 bits, 143 MHz
1 - ROLAND R8A02021AB0      - BGA   - Unknown
1 - ROLAND R05011856        - BGA   - Unknown
2 - ESMT M12L2561616A-7T    - TSSOP - 256Mb SDRAM, 4 x 4194304 words by 16 bits, 143 MHz
1 - ESMT M12L64164A-7T      - TSSOP - 64Mb SDRAM, 4 x 1048576 words by 16 bits, 143 MHz
1 - ALTERA MAXII EPM240T    - TQFP  - Tiny FPGA with internal pgm store
1 - ROLAND R02455212        - TQFP  - Unknown
1 - MXIO MX29GL256ELT2I-90Q - TSOP  - 256Mb (32M x 8/16M x 16) 90 ns NOR parallel Flash
1 - AKM AK4396VF            - SOP   - DAC, stereo, 192kHz sampling, 128x os, THD+N -100dB
1 - IC41?                   - TQFP  - Missing!  Connections to Flash

The small FPGA is interesting, it's probably processor glue and misc stuff (I prefer Lattice for this type of functionality). Lots of rather slow SDRAM, and only 32MB of NOR Flash ROM. Nice DAC! Several proprietary marked (and manufactured?) parts which is rather distressingly normal, though it's nice to see some fairly modern BGA packaging here.

There is a big spot for a TQFP chip that's clearly missing. It has connections to the Flash chip visible on the top layer. Looks like they had two major options here in terms of who knows what.

I should have removed the board to see if any major components are mounted on the back, but I was feeling lazy and risk averse.

[Linked Image]
Here you can see the key and weight assembly mechanism. Nothing all that revolutionary going on. The angled PWB underneath holds the rubber switches. One piece of 'U' bent metal at front serves as the upper and lower physical stops, another piece of metal at back cradles the majority of the assembly. Lots of plastic, really more than I like to see but this is par for the course.

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Three views of the hammer weights. The hammer weight grading has three steps, meaning there are 4 discrete grading groups total. If you notice the plastic assembly has a double strut here, between G# and A. Every octave has this - the key assembly is actually comprised of octave wide key groups with smaller groups on either end to make 88, which was a surprise. The rear metal channel is one long piece however.

To be continued... (PW only allows 8 pix/post)
Posted By: dewster

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 12:47 AM

Continued from previous post:

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The perspective isn't the best here, but I can vouch that the center of the pivot point is exactly 220 mm from the front edge of the key.

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The top-most key removed from the assembly. Pry the pivot tabs apart with a flat screwdriver and it comes right out. The key itself is mostly just air, and the hammer actuator is a rather flimsy looking structure. The fake ivory is a single solid piece of plastic glued to the fake wood colored plastic below. Lots of milky grease everywhere.

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Grease is the word. Here it's coating a guide that normally hides inside the front of the key.

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Here is the hammer assembly, a combination of plastic and stamped metal, with extra grease at the pivot point. That orange thing is a flap of rubber that imparts a subtle pseudo escapement feel.

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A close-up of the pseudo-escapement rubber flap. When the key is depressed it pushes the near end of the hammer assembly down, which causes the other end to pivot up. Part of it comes in contact with the end of the rubber flap, pressing the flap against the top piece of gray plastic. If the key is pressed further it overcomes the rubber and flips past it. When the key is released the rubber is again encountered, but with almost no resistance because it isn't backed by the gray plastic in that direction. So you only feel this fairly subtle rubbery point resistance when slowly playing the key in the down direction. Note copious grease.

[Linked Image]
The hammer assemblies pretty much just pop right out with a little tug. IIRC, the two bumps to the lower left actuate the rubber position switches. Looking through to the next key you can see its key actuator resting in the left side cup of its hammer assembly. No springs anywhere that I could see.

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Using a precision scale (OMG! IT'S A DRUG SCALE!!) to weigh the hammer assembly. Lightest hammer grading group weighs 39.2 grams, heaviest weights 41.2 grams. I didn't expect a lot of difference, but this 2 gram 5% difference is so slight it's rather shocking.

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A hammer from the lightest grade group on top of one from the heaviest. The extra 2g of steel is positioned on top and to the rear. Given a long boring afternoon one could probably hand grind all to roughly the same dimensions. One could also remove the weight by drilling the hole to a larger diameter - it's probably located close enough to the end that doing so wouldn't mess with the dynamics of the action much. Too bad I don't want heavier keys, it would be child's play to thread that hole and add weight via screws and washers.

In conclusion, if you find your NX lolling around the house naked, when putting it back together you should turn the self-tapping screws counterclockwise while applying downward pressure until you feel them pop down a little. Stop turning at that point and reverse direction. This will ensure that you aren't cutting new threads when reinstalling them. In terms of which ones to install first, start in the center and work your way out to the edges. Don't tighten any of them until they are all in there slightly snug, again working outwards from the middle. Don't over tighten, that can deform the chipboard. Your NX will love you for it.
Posted By: voxpops

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 12:48 AM

Well done, Dewster! We knew you couldn't resist. When you get the hacksaw out, can you record it on video, please?

The upper parts of those keys look a great deal stronger than Kawai's.
Posted By: dewster

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 12:51 AM

Originally Posted by voxpops
Well done, Dewster! We knew you couldn't resist.

I'll admit, when it arrived via UPS my screwdriver finger got itchy.
Posted By: Kawai James

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 01:26 AM

Interesting stuff, thanks dewster!

James
x
Posted By: HwyStar

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 01:54 AM

Very cool pictures Dewster, Thanks!

I would have been scared to death to take it apart. I had thoughts of regulating my board to be 55 to 52 grams but the more I thought about it... Nope, that is not for me.

No screws left over after you put it back together, right?

Michael Bolton of Office Space: "PC Load Letter"? What the f#&% does that mean?

Posted By: James Pun

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 02:08 AM

Thanks Dewster!
Posted By: Dr Popper

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 03:44 AM

You're completely nuts Dewster ...but we love it !!!!!
Posted By: Siriosys

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 06:33 AM

Awesome tear-down Dewster!

......I bet your wife's thankful you don't own one of these grin

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Posted By: safari70

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 10:14 PM

Originally Posted by dewster
Here it's coating a guide that normally hides inside the front of the key.


Hi Dewster, you think replacing the cloth strips under the front of the keys with slightly thicker ones improves the slightly hard bottoming of the keys (w/o messing up the overall action)?

Cheers.
Posted By: dewster

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 10:42 PM

Originally Posted by safari70
Hi Dewster, you think replacing the cloth strips under the front of the keys with slightly thicker ones improves the slightly hard bottoming of the keys (w/o messing up the overall action)?

I'm pretty sure that would work. It's probably some kind of hard felt. You might be able to just stick some softer felt on top of what's already there.

Do you find the NX key bottoming particularly hard?
Posted By: safari70

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 11:14 PM

Originally Posted by dewster
Originally Posted by safari70
Hi Dewster, you think replacing the cloth strips under the front of the keys with slightly thicker ones improves the slightly hard bottoming of the keys (w/o messing up the overall action)?

I'm pretty sure that would work. It's probably some kind of hard felt. You might be able to just stick some softer felt on top of what's already there.

Do you find the NX key bottoming particularly hard?


I recently picked up an FP-7F which i'm assuming uses similar keybed. Overall i really like the action, which i think provides decent control over dynamics and is very enjoyable to play... (I liked it better than the Kawai MP10's which i felt was unnaturally stiff)... if i really want to nitpick i would have preferred a slightly 'softer' key bottoming but it's not a big deal...
Cheers.
Posted By: dewster

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 11:15 PM

Extra NX Nakidity!

Today while doing the "DPs Exposed!" post I remembered PW member "blueston" had posted some photos showing the "brain" board of the RD-700GX. So I "borrowed" a pic from that thread and combined it with an overexposed one I took of the NX board. I corrected the aspect ratios to rectangular, scaled them to be the same size, and jamed them together into a single image for easy visual comparison:

[Linked Image]

The NX board is on top, GX on the bottom. It's clear that the NX board is a re-spin of the GX board, though not a drastic one as most components are in much the same places on both. On the left there are pads for 4 (ROM?) parts on the GX, one of which is populated, and only 3 spots on the NX, none of which are populated.

They both have that same huge missing chip spot, and the GX has room for two NOR Flash chips just to the left of that, one of which they populated with a 128Mb part. On the NX there is only a spot for one, and it has a 256Mb part installed there.

Now I wish I'd removed the board and looked for components on the back when I was under the hood, perhaps there's more Flash to be found. Would have been interesting to see what they did with the expansion bus on the NX too. Oh well, just thought I'd share this.
Posted By: Kawai James

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/28/11 11:47 PM

Does the NX still have the expansion port, like the GX?

James
x
Posted By: dewster

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/29/11 12:13 AM

Originally Posted by Kawai James
Does the NX still have the expansion port, like the GX?

Not externally, though I wonder if there are vestiges of it on the back of the control PWB.
Posted By: Kona_V-Piano

Re: NEKID PICHURES!! (Roland RD-700NX) - 09/29/11 03:52 AM

Awesome job Dewster:)
Posted By: Mikecanada

Re: NEKID PICHURES!! (Roland RD-700NX) - 12/31/11 01:02 PM

Great work Blueston and Dewster!

I have an out of warranty problem with my RD 300gx, one key alone is too loud, it sounds like I have struck it harder and quicker.
It consistently does the same thing. From what I see from your efforts is I could access the interface where key meets electronics.
Has anyone had any experiance with this?

Thank you
Posted By: 36251

Re: NEKID PICHURES!! (Roland RD-700NX) - 12/31/11 01:28 PM

This is great stuff. Wow, one tiny little piece of rubber added and the PR department gets to boast of the latest innovation in DP actions - priceless.
Posted By: blueston

Re: NEKID PICHURES!! (Roland RD-700NX) - 12/31/11 03:33 PM

Hey Dewster, this is really cool, thanks. This is a nice and more detailed follow up to the GX one I did. But I did not have the guts to take a key assembly off like you did!

Everything looks almost identical between the two and it's interesting to see the Motherboard has not changed very much.

Just be careful you don't put a screw thru the main ribbon cable when you reassemble it. On the GX there was an extra hole right over that which of course my repair shop found using Murphy's Law.

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