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CDX reverse engineering


Guest rasteri

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Guest rasteri

update by cd rather it is impossible because it probably will be a problem with the checksums and modulation VAW, or am I wrong?

I don't know, I tried to reverse engineer the CD update format but got nowhere. Do you guys know any more about it?

 

Also, are you able to dump IC101 on the control board? That would be very useful.

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Also I want to point that in the folder labeled 3700 we have documentation about dns3700 including service notes too ;}

 

https://drive.google.com/open?id=0B4ftWaZ6ARSUcDBiaV9uOXBKOFk

as if he was such a service manual for cdx it was by the end of the work.

 

ok tomorrow I will try to play with logic analyzer but not promise that tomorrow I will report.

Edited by borys.stw
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as if he was such a service manual for cdx it was by the end of the work.

 

 

 

Borys meant - "If we would have this type of manual for cdx - we would end the mod in one week."

 

I have trouble in encrypting his english - I can't even imagine - how much do others have to struggle... ;)

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update by cd rather it is impossible because it probably will be a problem with the checksums and modulation VAW, or am I wrong?

I don't know, I tried to reverse engineer the CD update format but got nowhere. Do you guys know any more about it?

 

Also, are you able to dump IC101 on the control board? That would be very useful.

 

 

ok, no problem, tomorrow morning upload dump IC101 to google drive

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as if he was such a service manual for cdx it was by the end of the work.

Borys meant - "If we would have this type of manual for cdx - we would end the mod in one week."

 

I have trouble in encrypting his english - I can't even imagine - how much do others have to struggle... ;)

Well... for cdx (and also the firmware I linked before...) was already in the drive since the first moment. It's from those where Rasteri and I took schematics. Rasteri linked a page ago when you asked for hdx one.

 

https://drive.google.com/open?id=0B4ftWaZ6ARSUQ2VmakxnNFc5R2c

 

;)

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Guest rasteri

Guys, the IC101 is locked, no way to dump it... ;/

 

Hmm. I wonder if we could sniff the firmware as it's being updated or something.

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  • 1 month later...

First, I would like to thank everyone involved in the project. I know how hard it is and how much time it takes to do it.

When the Numark CDX was launched (with the name was CDX1 inclusive) it was a dream, the real feel of the vinyl with a great modernity (for the time) and still with a better price than the Technics.
I could not resist and buy a pair, because the feel was really good, like the MK2 turntables where I learned to play and with some interesting features!

But soon the dream became a nightmare with the optical drive, even using CDX only at home and very little, one or two days a week, two or three hours, in less than a year I've had problems.
But after the first exchange of optical drives, the CDXs were never the same. New drives, when they correctly read the CDs (which was rare with MP3s), only ran for three to six months.
In short, I never had the confidence to risk using them in presentations, in the only one I tried, I had serious problems in reading CDs.

They are brand new as in the store, I ended up saving them in their boxes (with their accessories in the original plastic bags, including the numark vs technics poster that had been accompanying them) inside the wardrobe for the last 5 years.

 

These days I was thinking of putting my old electronics course into practice and I started researching about emulating an optical drive with arduino, or something like that.
Or that it could at least make CDX work at least with timecode CDs without the risk of stopping at any time.

I was very happy to find this topic, with people so committed!
I'm looking forward to the solution!

Numark's engineering was rather unfortunate, a great idea destroyed by gross errors. Maybe if the equipment had been built robustly, would have sold well, if modernized for USB reading, evolved into a midi controller too and today could be fighting (even better) with the Pioneer CDJ2000.

(Sorry for my English, I'm Brazilian and I used google translator, and for writing so much too)

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  • 2 weeks later...
Guest rasteri

Nice to see this thread going, rasteri I recognise you from the skratchlounge I used the name 'turntablist tikka' there back in the day.

 

Oh hey man! Good to hear from you again.

 

I feel really bad that I can't spend much time on this project but I guess it was always gonna be a long-term thing. I'm definitely not gonna give up on it though.

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  • 2 weeks later...
Guest rasteri

hmm anyone know what the cd laser potentiometer should be set to?

 

The laser is factory calibrated, don't mess with it. If the laser sled is fucked you can replace it - generic parts are still available.

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yeahhhhhhhhh... muchly appreciate the advice - that said it may be a bit late for me.. oops. :) I remember roughly where it should be but I imagine from what you have said that wont be enough.

 

ksm213ccm seems like a good replacement.

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hmm,

 

I was just re-reading what you said previously about emulating the output of the CXD3068Q, I've also read through tons of CD documentation (red book etc) to get my head around this CDX situation.. I agree that the best course of action here is very likely to be emulating this IC's output.

 

I'm willing to invest some time on this project.

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Guest rasteri

hmm,

 

I was just re-reading what you said previously about emulating the output of the CXD3068Q, I've also read through tons of CD documentation (red book etc) to get my head around this CDX situation.. I agree that the best course of action here is very likely to be emulating this IC's output.

 

I'm willing to invest some time on this project.

 

 

I reconsidered that approach because I thought a more "satisfying" solution would be to hack the existing CDX firmware to speak directly to a USB drive, but I couldn't get a dump of the control IC or reverse engineer the firmware update format. I was considering running the HDX firmware on the CDX and seeing if that was close enough, but I can't find an HDX service manual so have no idea how likely that is to work.

 

So perhaps you're right - emulating the servo controller might be the way to do this.

 

I've spent a lot of time poring over logic analyser logs between the CDX and the CXD3068Q, and wrote CXD3068Q emulator that is (more or less) able to fool the CDX into thinking an audio CD is present but it's in very rough form. I never figured out data CD emulation, which would be preferable (so you'd get menus etc).

 

I did also think maybe we could take control of the DSP/control reset lines and LCD to implement a menu system to select mp3s, then hand control back to the CDX once we've built a virtual audio CD.

 

It's cool that you've spent lots of time looking over the red book - a lot of it is pretty opaque but I got there in the end (the subcode decoding and CRC LFSRs etc totally fucked with my head). Have you got any info that might be useful?

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I've done nothing except be inspired by your research. I'm going to need to fix my laser adjustment fuck up. I've got 2 cdx both are faulty so I feel a bit disabled for the moment, I've ordered a few replacement laser modules and will do some trial and error adjustments to see if I can get one working again in the meantime.

 

Besides doing nothing useful i'm reading through CXD3068Q to absorb some of it.

 

I hope to contribute something useful soon!

Edited by electronoob
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yeah pretty much can't recover these cd drives, I'm dead in the water until replacements arrive, I think.

 

considered removing almost all of the electronics and just use the turntable+encoder information? I don't see the point of pre-fader effects.

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Guest rasteri

considered removing almost all of the electronics and just use the turntable+encoder information? I don't see the point of pre-fader effects.

I think a lot of the magic comes from the very responsive and nice-sounding DSP code.

 

But perhaps you're right, maybe re-implementing everything from scratch would be viable. Especially as most of the work has already been done in projects like xwax.

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considered removing almost all of the electronics and just use the turntable+encoder information? I don't see the point of pre-fader effects.

I think a lot of the magic comes from the very responsive and nice-sounding DSP code.But perhaps you're right, maybe re-implementing everything from scratch would be viable. Especially as most of the work has already been done in projects like xwax.

Great Rasteri!

My humble opinion if it's possible to implement usb read an easy way it could value the effort but if not then hack it directly into something new like your scratcher is the way to go.

https://youtu.be/MAbJCSvKqgY

Said that I will love to thumb drive and portablist mod. How can I help?

So implement pideck should be straightforward since ximo had implemented rotary encoder in the code (for library search but it should be "easy" to adapt the code adding the encoder part from your scratcher project too) and putting the touchscreen over the regular cdx one to keep the service tools still accessible...

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