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ChromaTalk Archives: January 2004

My Chroma Lives

Doug Terrebonne [21030114]

I'm happy to announce that Chroma #21030401 is back from the dead! :-) I got this a couple years ago with extensive battery leak damage all over the computer board. I found another computer board and got it working again. To my surprise the original power supply an all voice boards seem to work fine. The only probs seem to be there is one key on the keyboard that causes it the synth to go haywire when played and the parameter slider goes a little nuts when moved to 0.

Doug

David Clarke [21030085++]

Doug Terrebonne wrote:

I'm happy to announce that Chroma #21030401 is back from the dead! :-)

Doug - glad to hear news of the ressurection!

The only probs seem to be there is one key on the keyboard that causes it the synth to go haywire when played

Take a peek down by the contacts for that key and see if anything looks 'bad' (like the metal arms with the contacts being bent so that they're touching one another when they shouldn't, or chunks of 'stuff' shorting between the contacts)

... and the parameter slider goes a little nuts when moved to 0.

Can you describe that a bit more? Is it just that the parameter in the display window won't stabilize (jumps all over the place), or does the Chroma itself loose its mind?

Olli [21010284]

hi there congrads, too,

i have done the same sort of job a couple of weeks ago. mone just needed that you tweek the key contacts manually and then it worked.

Doug Terrebonne [21030114]

--- David Clarke wrote:

Take a peek down by the contacts for that key and see if anything looks 'bad' (like the metal arms with the contacts being bent so that they're

They look pretty clean... Now what I'm getting is a random stuck note every so often...

Can you describe that a bit more? Is it just that the parameter in the display window won't stabilize (jumps all over the place), or does the Chroma itself loose its mind?

The value just jumps around a bit...

By the way, this Chroma doesn't have MIDI. Are the factory patches available somewhere as an audio file?

Thanks,
Doug

Chris Ryan [21030691]

On Jan 14, 2004, at 5:56 PM, Doug Terrebonne wrote:

By the way, this Chroma doesn't have MIDI. Are the factory patches available somewhere as an audio file?

Factory Set 5, at least, is available in .wav format [see Patch Downloads].

Chris

Doug Terrebonne [21030114]

--- Chris Ryan wrote:

Factory Set 5, at least, is available in QuickTime format.

Great! Now can someone tell me what pin on the Chroma cassette DIN connector I can connect to the output of a standard cassette deck?

Thanks, Doug

Doug Terrebonne [21030114]

Nevermind... I figured it out from the schematic... :-)

Does that sysex-to-audio program work well?

Jimmy Moyer [21030184]

In a message dated 1/14/2004 8:57:31 PM Eastern Standard Time, bigfootstudios@yahoo.com writes:

Can you describe that a bit more? Is it just that the parameter in the display window won't stabilize (jumps all over the place), or does the Chroma itself loose its mind?

The value just jumps around a bit... I had something like this on my Chroma - actually, all the ADC inputs jumped around, slider, pedals, etc. Traced to unstable reference voltage at the converter caused by loose screws on the big filter cap in the power supply. Check those first.

Olli [21010284]

Am Donnerstag, 15.01.04 um 04:35 Uhr schrieb Doug Terrebonne:

Does that sysex-to-audio program work well?

i have tried with the audio file of bank 5 which chris has posted on the site and it worked with my chroma

Chroma Panel (+ circuit boards), channel mother board and channel board on eBay

David Clarke [21030085++]

These three items are currently listed up on Ebay. Anybody know the owner and/or might the owner be here on the list?

The listing comments indicate that the parts were taken from a working Chroma - but after those parts are removed, the Chroma isn't going to be doing too much.

(If another Chroma has been taken out of circulation, it would sort of be nice to know the S/N of it ...)

Olli [21010284]

hi david.

i have checked and can't find the items on ebay. do you have the link?

btw, i have sent you another mail on audio file formats. have you received that one?

best wishes

olli

Olli [21010284]

hi david

do my mails go into the junk ? :-) i didnt find teh ad an wondered if you could send me the link i have sent you a couple of other mails, too best

olli

Chris Ryan [21030691]

On Jan 14, 2004, at 2:13 PM, Olli wrote:

i didnt find teh ad an wondered if you could send me the link

  • Rhodes Chroma channel mother board: Item number 2372941562
  • Rhodes Chroma voice card: Item number 2372943892
  • Rhodes Chroma front panel: Item number 2372943015 (auction ended)

Chris

Olli [21010284]

thanks chris
i just bought the channelboard.
i figured tat these bight be the hardest to repair...
the DCBs do not to seem to hard.
best wishes
olli

Olli [21010284]

actually i don't really understand why you would want to sell parts of a functioning synth....

you get more if you sell it as a synth.... hmmm quite sad actually.

expander

Olli [21010284]

hi there

i really love the Chroma and might want to add an expander. to you have an idea how much these might sell on the market? i have never seen one though.

olli

Rich HIlleman [21030351+]

I have an expander and two chroma keyboards. Expanders seem to be going for about 150% of similar grades of instruments with similar extras. My Expander cost about $1800, if I remember, and I didn't pay much over $1000 for either of my keyboards. One real advantage is that they work a little more reliably. Key contacts are my number one maintance item on my Chroma Keyboard. My current working keyboard is a consolidation of the best of my two keyboards, including the keyboard contact strips. I still find I need to clean them nearly everytime I use them to get it into a working state. I love the action and the sound and look of the Chroma, but it is nearly the highest maintance item I have, and I have synclavier, fairlight, and a couple of CS80s.

My expander is hooked up by Midi to my Suitcase 73 (another story). It doesn't have the soft butter feel of a working Chroma Keyboard. In some ways it seems more like a Rhodes.....

Olli [21010284]

i agree, the chroma is the best keyboard feel i have
and one of the last synths i would ever sell together with my LAMM.

i am looking to acquire a CS80, too. quite highly rated though. i dont feel like spending 3000 euros...

i am offered one for 1500 euros... but its a little far away.

once i didn't buy a MINT CS in new york. back in 1998 it was at 1500 at a dealer... please hit me.. :-)

how many CS do you have?

Olli [21010284]

when i got mine, three keys didn't work, once i started playing around with the contacts and played the instrument regularly, this problem seemed to solve itself...

Rich Hilleman [21030351+]

Good for you. That hasn't been my experience. It has required pretty constant attention to keep a sensitive, functional system. I'm glad for all that have good experiences. I think the expander is also more expensive because is takes less space for the same function, has less parts to break and is a lot less common.

I looked it up, it was about $1850 for mine, about 15 months ago. I haven't seen one anywhere since. I see one on Big City Music, at $1799. Sounds like that is close to the going price. Roger's stuff is usually in pretty good shape.

richh

Snd2Wav Converter for Syx2Tape

Doug Terrebonne [21030114]

I couldn't get any program on my PC to read the .SND files generated by the Syx2Tape converter. But I have found a Snd2Wav conversion program here that will convert them to standard .WAV files - the "snd2wav.zip" at http://medlem.spray.se/converters/

When you run the Snd2Wav program be sure to put in a "-F8012" option to handle the 8KHz sample rate of the .SND file...

Doug

Doug Terrebonne [21030114]

Oops, actually the .SND files are 22KHz so use "-F22050" when you run Snd2Wav...

Doug

little tech problem

Olli [21010284]

hi all,

hi i am back with one tech question.

today, i have received my new molex connectors for the DCBs.

18 USD value, 11 USD handling charge, 17 USD shipping. total 48 USD.

french customs: 30 USD! no joke. (no customs actually, only handling fee and VAT, this is sick and i PAY them for this...) anyway....

i have now replaced the defectious connectors on my DCBs with my new PACE MBT soldering-desoldering station. works great! (btw. no customs on that unit... please explain me)

problem, all cards seem to work fine now slot five often signals an error. i got the impression that it does not control the resonance on channel A which seems to be set randomly. you can't change it. if by coincidence on max, it signals no error, if not, channel 5 signals an error. there seems to be a prob with the channel motherboard.

any suggestions?

olli

David Clarke [21030085++]

Olli - if this hasn't already been resolved, you may wish to look at Z11 on the channel motherboard. The STB0 signal (available on J7-7 for slot 5) controls the RES bits for the voice-card, and so if something has gone awry with that signal, it could have a similar effect as the one you mention. At the very least, it might be worth 'scoping out that signal to see what is happening.

Good luck with your debug efforts. Let us know how you make out.

David

Olli [21010284]

hi david,

i am happy to hear that my primitive analysis of the schema did yield the same result !

well i changed Z11 and a couple of other chips on the board since i can only be th CHMB in my opinion.

right now the chroma is closed but if i remember correctly, i changed Z11, Z9, Z3 and Z8.

unfortunately, it still shows the same strange behaviour...

best

olli

David Clarke [21030085++]

well i changed Z11 and a couple of other chips on the board since i can only be th CHMB in my opinion. right now the chroma is closed but if i remember correctly, i changed Z11, Z9, Z3 and Z8.

Olli - it would be interesting to remove all the voice-cards, except the on in slot 5 - and to confirm that the board still fails.

Just as a double-double-check, then move just that one card to another slot, and confirm that it does not fail (really confirming that the problem is only with the specific slot - and that the slot failure is not being impacted by behaviours of cards in other slots).

Assuming the problem does follow the slot, it may make sense to watch the signals available on the 4 molex connectors during a tune attempt. You can observe the behaviour both when the card is in slot 5 and when it is in any other slot. Hopefully that will point to the specific signal that is different.

Olli [21010284]

Olli - it would be interesting to remove all the voice-cards, except the on in slot 5 - and to confirm that the board still fails.

well that is what i have done. it only occurs on slot 5

Just as a double-double-check, then move just that one card to another slot, and confirm that it does not fail (really confirming that the problem is only with the specific slot - and that the slot failure is not being impacted by behaviours of cards in other slots).

Assuming the problem does follow the slot, it may make sense to watch the signals available on the 4 molex connectors during a tune attempt. You can observe the behaviour both when the card is in slot 5 and when it is in any other slot. Hopefully that will point to the specific signal that is different.

ok i have an oszilloscope. what do you mean by "watch the signals"? what should i do? .... :-) just connect it to any of the contacts and see?

best and thanks again

olli

David Clarke [21030085++]

ok i have an oszilloscope. what do you mean by "watch the signals"? what should i do? .... :-) just connect it to any of the contacts and see?

Yes - that is pretty much it. The general philosophy is that if the same card doesn't work in Slot 5 but does work in another slot - then there has to be something 'different' with the signals going to the card when it is in slot 5.

The first tests will be very subjective - simply to watch each signal and note 'generally' how it looks and then attempt to determine if it looks fundamentally different than the same signal when the card is in a 'working' slot.