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ChromaTalk Archives: November 2013

Go to first message in thread, October 2013

Brian McCully [21030361]

Speaking of haunted Chroma's...

I have possession of the infamous 'no serial, earth tone, halloween' Chroma and while it was working fine until recently, it started freezing up. It started by not responding to MIDI, then eventually when power cycled, many of the panel LED's remain all lit up, but no Program readout LEDs.

It has a CC+, SPSU and pressure sensor kit installed. At first it took some time (1/2 hour) to freeze once it started failing, but now does so after 5 minutes of a cold start boot-up. It seems as though it is a thermal issue but ...

I took the instrument to a local service tech and after checking the power supply (relatively new SPSU) voltage and swapping out some firmware EEPROMs that had recently been swapped, the instrument is still freezing up on bootup. He has re-seated connectors, and checked voltage so far (solid 5V from the supply). He hasn't spent a lot of time yet on it other than going through some basics.

I have a couple of questions for the Chroma gurus-at-large, as the tech is not on the forum. All the symptoms point to a bad power supply as far as the on-line "HARDWARE FAULT DIAGNOSIS & REPAIR" is concerned. but the SPSU seems to be yielding 5V okay.

The troubleshooting portion of the CC+ documentation mentions the following: "If the Chroma has been retrofitted with a switching power supply, confirm that the 'minimum load' requirement is achieved with the lower-power CC+. Confirm that the Chroma will still boot properly if the original CPU is reinstalled"

Is this recommendation subject to what has been a working unit for at least a couple of solid months? I have the original main processor board/parts from another Chroma but I didn't know if it would be useful to re-install this as a course of action. i,e, this broken Chroma was purchased with the CC+ already installed (and I replaced the fried power supply (not an original) on it with an SPSU). Are there schematics available for the CC+ board? Test points?

Are there any other areas that the tech can check that are known problems for a freeze? I also just delivered my other Chroma to the tech to do some basic comparisons and board swaps as necessary, as it has the same modifications as the earth tone unit.

thanks in advance, Brian

Luca Sasdelli [21010226]

Hi Brian,

what if you toggle the RESET button on SPSU PCB? Does the LEDs react in some way?


Brian McCully [21030361]

Hi Luca,

Good prompt! Last I checked in, I asked whether he'd checked the reset and he said it didn't do anything. He happened to have the other Chroma next to it and when he found out that it reset fine on the working unit, and that a ground wire may have been astray on the repair unit, he said he'd call me back in a while. That was an hour ago... (oh the repair clock is ticking...)

thanks!! -Brian

Chroma 2103-0018 For Sale on eBay

Michael McInnis [21030027]

Nice instrument on eBay: [item #181256668117]



Pictures from the auction:

Michael McInnis [21030027]

Whoops...should have said 2103-0018!



Michael McInnis

Howie Shen [21030552]

A word of warning: in the photos it looks like only 7 voice cards are present. Maybe my eyes deceive me? Look carefully and you can barely make out the empty grooves in the card rack where voice 8 should be in the top right. Or do my eyes deceive me?

I sent the following message to the seller, and will share his response if I get one:

"Hi in the photos it looks like only 7 voice cards are present, you can see the grooves in the sides of the card rack where card 8 should slide in like the others (4 cards on the left, and should be 4 on the right, too). Can you explain? This is obviously a big deal, since the synth can't be considered anywhere near fully working if it is missing! Thanks."


Eric W. Mattei [21030443+]

It sure looks like it's missing to me, Howie. I'm not one of the gurus around here. But I didn't see anyone else reply to this email, and I've seen the inside of my Chroma many times in the last 30 years. That Chroma only has 7 voice cards. It's easy to see the trim pots and there are only 3 pairs of trim pots on the right. That's my two cents.

- Eric

Michael McInnis [21030027]

Yeah, one card shy.



Lars Johansson [21030632]

Yep, seven cards installed. Missing one.


Werner Schöenenberger [21010114]

Second that - 7 voice boards instead 8


Howie Shen [21030552]

The Ebay seller wrote back to me acknowledging that the Chroma is indeed missing a channel card, and that he doesn't know the story behind why it is missing. Therefore the unit will be sold missing those voices.

Its good that he was responsive and honest about it, and has updated the auction listing with that information. But I can't help but wonder: if he didn't even realize voices were missing, how well does he really know the synth to be able to claim that there are no other functional issues?


Werner Schöenenberger [21010114]

Maybe he used the instrument but did not check that there are less voices. I never tried to play a Chroma with one card missing - maybe it works as usual and you would have to count voices.


Andrew Dalebrook [21010180]

...apart from the Err[x] message...

The Chroma has landed !

Peter-Jan Kleevens [21010014]

After 4 years of abcense due to heavy repairs my Chroma (sn 21010014) has returned on its nest. I'm so unbelievably happy ! It took a horrible long time but in the end Patrick Schoon from the Service Connection (Holland) did a remarkable job. Super stable oscillators, new power supply, cooling fan, super powerful new tapper a lot of new chips and stuff. But still the old original engine, no C++. For now I think I'll keep it that way I don't want to miss her again.....

Best regards,

Dryden Chambers

Nice pix! Is your ipad editing the Chroma yet ?

Btw, I have found it's best not to put anything on top of my Chroma as it puts wight down on the top of the voice cards. YMMV.


Brian McCully [21030361]

I believe an iPad editor needs MIDI (i.e. a CC+ or Syntech interface) to function...

Peter-Jan Kleevens [21010014]

The Chroma is MIDi-ed . I use the iPad as remote for Logic Pro X on the Mac. Thanks for the advice about the voice cards. I'll take the Korg 800DV of the Chroma.


Dryden Chambers

I use a ipad for Logic X too! ; )

I picked up a old Ipad mk1to use with the Chroma only, it was just over $180 including Touch Osc, a used usb kit, stand, and cheap usb midi cable.


Michael McInnis [21030027]

My Korg 800DV is above my Chroma too...though its on a stand.



Brian McCully [21030361]

fwiw I didn't understand how the Chroma could fully talk iPad without a CC+ (which PJ mentioned his Chroma did not have...). Are there other ways of fully interfacing all the Chroma parameters?

(Sound Diver is long dead unless you have like OSX 10.1. I can't get the Cubase editor to load up. Sound Quest has never worked for me and none of these have iPad hooks(?))

How does Logic X via an iPad interface with a Chroma? Is some version of Sound Diver alive again?

I just built a Cycling74 MAX Chroma editor with an iPad interface. Works fine. Works with any sequencer/DAW/whatever is MIDI. It uses the CC+ via sys-ex or MIDI CC's. What else is out there?

David Hobson [21030506]

Hello Brian,

From my own personal experience,

If you do not have the CC+ you can still use a syntech (Chroma Cult) midi interface, offered by Ken Ypparila [21030229], for midi communication.

The Chroma uses .syx communication and will listen for most of its internal parameters without the CC+ CPU. From what I was told (By David Clarke [21030085++]) you cannot access ALL of the midi parameters of the Chroma without the CC+, but most of them.

But before I tried using my "Behringer BCR2000" (see: Behringer BCR2000 Projects) with my Chroma (which already had a syntech interface) I went ahead and purchased the CC+ CPU and Midi interconnection kit.

Now that I have the BCR2000, CC+ with midi I am able to quickly modify all of the internals with the knobs on the is great! And in my opinion, the BCR is the way to go. You don't have to fumble about trying to "turn" virtual just reach up and turn the knob.

On the Rhodes Chroma site there is that page [BCR2000 Set Up] dedicated to the BCR2000 with a .syx template you can load into it so it is already programmed for use with the Chroma, that is what I use.

Now, the only question (important question) is whether or not you can use the BCR2000 with the syntech midi interface without the CC+...I believe so, but I could be wrong. You could wait for an answer here or contact David Clarke directly...he would know that, and is patient with questions.

Anyway, whoever answers your question, if you are able to use the BCR2000 with the Chroma via a syntech interface, I highly recommend it as the way to go ( I like knobs.)

And...I own a Chroma Cult/syntech midi interface that I would sell at a fair price to You.

This is all my personal opinion and is not meant to bash the little iPad thingy.

I hope this helps, I have attached a picture of my Chroma with the BCR2000 on top. David Hobson.

P.S. I bought my BCR for about 200.00 usd.

Peter-Jan Kleevens [21010014]

Wow perfect info !

thank you.


Brian McCully [21030361]

Hi David,

Thanks for sharing your experience with the Behringer knob box. I do appreciate the need to grab a knob. Or fader. As controllers. The familiarity of a hardware layout also has benefits.

The iPad experience is different, and I'm not totally sold on it yet. I would eventually like to see a marriage of knobs, faders and touch screen(s) in a hardware package, that could flexibly update itself to control any audio situation. I held off purchasing an iPad until this last year - where I can now see using it 'with other tools in such a package, and having the capability to remotely control any studio hardware, without dedicating a control surface to only one target - e.g. the Behringer only for the Chroma. Since July I've developed bi-directional editors for the Roland JX-8P (the MKS-70 is next), Korg Polysix, Nord Stage EX and the Chroma, as well as just finishing a Roland GT-6 interface, as a pre-cursor to the closely related protocols for the VG-88 and VG-99 series, and other GT boxes.

The drawbacks of the iPad I've found are latency, time spent booting the associated app and the somewhat coarse resolution when trying to make fine adjustments. Screen knob control placement is critical, so one doesn't run out of room on a swipe. An 'all faders' screen can be a bit non-intuitive. But the UI is flexible and any number of screens can be deployed and controllers re-sized in numbers and shapes...

A nice thing about an iPad is that it is lightweight and can be placed on a mic stand or music stand and multiples of them side by side for more controller coverage.

With guitar multi-effect pedalboards (which I also use), one must get down on their knees to edit them, with an iPad editor that's not necessary. A knob-box hardware control surface is a little 'bulky' for this task and the labeling situation would be a difficult for editing multiple devices (but overlays are possible).

(Whether my editors are ever commercial or shareware situations is another ball of wax, but in the meanwhile it is interesting interfacing, and developing the UI in a non-hardware situation.)

I have two Syntech interfaces as well as two CC+ installations and am familiar with both the protocols. The protocols are listed on the Chroma site. The MIDI cc (continuous controller) implementation for the Syntech interace is somewhat of a subset of the CC+, the latter of which covers all of the synth parameters (but not the Link and keyboard related controls). I've studied the protocols quite thoroughly in creating the editor. The Sys-ex data can be used to derive the Chroma keyboard related parameters, that the CC+ doesn't address, and as well to control the parameters that the Syntech interface didn't address as CC controllable. Thank you for your offer for your interface. And yes David Clarke [21030085++] has been very kind in addressing my questions.

I imagine that managing the Chroma bitmapped sys-ex in an iPad programming environment would be quite a task (if necessary...). That's why I'm using MAX, as the benefits are that I can create a 'stock' PC/Mac UI (i.e. large screen), include iPad screen extensions, and also create the I/O hooks for external hardware such as a HUI related device (Mackie Control, Behringer box, etc.). Plus I've been using MAX for a long time, so it's not such a steep learning curve for me to use it.

regards, Brian

David Hobson [21030506]

Thanks for that info Brian,

Keep up the experimentation! That is where innovation comes from.

On a slightly different note:

I am making a video of the Chroma which I will upload to Youtoob. I will fully exercise the capabilities of the Chroma, not just play the factory a matter of fact I will not play any factory patches.

I believe this synth should be seen for what it is and how it can sound. I will use the BCR2000 to take it through its paces, and use the opportunity to promote the Site, the upgrades and my own work with "Music Inclusive" of which I am a partner.

I think the public (or at least 2 or 3 people who see my should see more than the chroma looking like a DX7, if you know what I mean.

So, maybe later this week..or next week. When I post it I will provide the link.


Eric W. Mattei [21030443+]

The Chroma doesn't look like a DX7. The DX7 looks like a Chroma. :)

David Hobson [21030506]


You are does not look like a DX7 :)

Lets get this straight right now, I love my Chroma! If lovin' my Chroma is wrong I don't wanna' be right!

I am working on that video, and it is difficult not to make fun of Marc's just me, i'm sorry. I keep thinking of a long, sweeping epic that starts with some guy back in the 1800s dropping a wrench on another fellow which causes a chain of events that bring about the invention of the Chroma...But I will maintain! I will be normal and politically correct!

I hope that I do not lose my membership card.

Brian McCully [21030361]

Nor does the Expander look like a TX-7...or a suitcase full of them...

May your posting be an inspiration to us all, David.

cheers! -B

Jesper Ödemark [21010135]

The Chroma doesn't look like a DX7. The DX7 looks awful. :D

strange behavior fix.

Bruce Sklar [21030660]

Hi all

This is very basic, and many of you will know this, but I’ve found that re-seating the sound cards from time to time can fix all sorts of errant beeps squeaks and squawks and tuning issues that can emanate form the chroma seemingly inexplicably. Just be careful as the pin receptors on the cards are somewhat fragile and can bend out of position . A little gentle wiggling without pulling the pins out of the receipts seems to do the trick.

Bruce Sklar

Vermont, USA

Chroma owner we since 1984, now have the CC+.

Dryden Chambers

I will add, carefully cleaning the connectors (male and female) as well. I use Isopropyl alcohol and sometimes Caig Detoxit and Pro gold.

David Hobson [21030506]

I concur, and I will also mention that I use a long pencil with the eraser end to push down on the pin receptors when re-seating the voice cards. I do this so that the pin receptors do not take the full stress of making the connection.

Syntech MIDI Interface on eBay

Chris Ryan [21030691]

Item #331075434757, starting bid USD$99.00, no bids yet, ends November 30. "Excellent cosmetic condition." See Syntech/Chroma Cult MIDI Retrofit.

Picture from the auction:

Ugly marred membrane covering made prettier through tattoo machine washers!

David Hobson [21030506]


#8 Nylon Shoulder washers can be used to cover that ugly bit around the 4 screws on the control surface. Yes, no more ugly rotten wear visible!

I had to wrap a 1/8" strip of electrical tape (about 3/4" long) around the screw near the head to make the washer centered...but it was worth it for me.

Shoulder washers fit (the "shoulder" part of the washer) into the depression where the screw sits.

I have attached three photos.

Happy Thanksgiving to all who celebrate, Or just Happy day to those who do not.

David Hobson.

P.S. Still working on a Chroma Demo video.

David Hobson [21030506]

Hello again,

I have 100 of those washers. I would send 4-8 to anyone who send me a self addressed stamped envelope for free.

And if you have something better to share for this purpose, I would like to know.