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ChromaTalk Archives: April 2002

Rev 14 EPROMs

Tom Moravansky [21030431] · Tue, 2 Apr 2002 08:59:22 -0800 (PST)

OK. I downloaded the rev 14 EPROMs and burned them and now the Chroma is locked up. So, before I take the next step, I want to verify a few things with the folks here:

  1. the on-line EPROM files are OK
  2. Does IE change the files when you download them (an old IE problem where it tried to interpret the download and add <CR>/<LF>)
  3. Does anyone have the exact byte size for each of the files? All of my downloads have the exact same size of 2048 bytes.
  4. Does anyone have the checksums for each of the files?

related:

  • EPROM 36 (14), 36(14a) and 36(14b). From the various posts, I *think* the correct one is 14b.
  • Also, if the rev 12 unit had the Keyboard Scan 3 version, there's no reason to re-burn that, correct?

I wanted to trace the problem from the beginning.

Thanks

Erik Vellinga [21010286] · Tue, 2 Apr 2002 20:46:59 +0200

Hi Tom,

I have burned the EPROMs that I have downloaded from the site some time ago and my Chroma is working fine ever since. So, the Eprom files are OK. The only problem I encountered was that I was unable to program my "found /new" Eproms so I had to reprogram the originals from my Chroma..risky but it turned out OK. You are right to use the 14b for Nr. 36.

I also upgrated the keyboard scanning Eprom, but I do not think it is nessecary.

Are you sure the Eproms are programmed in the right way, can you verify their contents with your programmer? If they are plugged in their sockets without a missing "leg" you should be OK.

Good luck,

Erik

Tom Moravansky [21030431] · Tue, 2 Apr 2002 11:11:09 -0800 (PST)

I had a set of rev 12 EPROMs and dumped their contents to the PC. I erased the EPROMs and then used my PC-based EPROM burner to make rev 14's. The software automatically checks that the burn matches the memory contents. So, assuming I got the files to the PC uncorrupted, I think it's probable that the burn is good. The real way to tell is look at the checksums for each IC. That will help me verify that the EPROMs were burned OK.

Josue Arias [21010162] · Tue, 2 Apr 2002 22:41:46 +0200

Hi People,

I burned the rev14 eprom from the website about a month ago and my chroma also lockup... I was thinking that was afault in one of the eproms (I got them refurbished from old coin machines) but is strange that yours also locked up... I replaced them with the rev12 again and works fine, but now I get a heavy hit from the "pulser" inside the unit everytime I select programs or parameters....strange... Any clues?

Best Regards,

Josue.

David Clarke [21030085++] · Tue, 02 Apr 2002 20:12:39 -0500

Tom,

I can re-confirm that the images should be OK, as I often use them.

To be sure I've just re-downloaded the Rev 14's from the site and compared them against the original's here on my PC. All looks OK.

To follow-up on a couple of the other points - you should be OK with the existing keyscan code (it shouldn't prevent operation). Also, you should be safe in using any of the "14xCBS.obj" files - the only real differences are in the velocity/keyboard table (again, all should run fine).

Checksums are a bit iffy, as different programs often use different algorithms to do the calculation. That being said, here are the checksums (from my burner) for the 6 images I believe you're using:

File Checksum
14_cbs29.obj E61F
14_cbs30.obj 7DA6
14_cbs31.obj 9536
14_cbs32.obj 620B
14_cbs33.obj 69B1
14_cbs34.obj 5790
14_cbs35.obj 9754
14bcbs36.obj B6E9

If you're still experiencing difficulties, please feel free to download the code from the burned rev 14 eproms and send them to me (either in binary or hex form). I can then check this against what should be in each record.

(And if that also doesn't work out, let me know and I can probably provide you a set of known working Rev 14 PROMs).

Regards,

David

rev 14 + battery

Tom Moravansky [21030431] · Thu, 4 Apr 2002 04:39:03 -0800 (PST)

Well, I had a surprise visit from Russ yesterday evening. He dropped off a Chroma board with factory rev 14's on it. I'll pop those out, do some comparisons and post results this weekend.

Also - has anyone ever replaced the regular batteries with a Lithium? My Chroma suffered from Duracell acid leak. I don't think much (any) of the board is damaged, but the battery holder needs to be replaced. I figured that while I'm in there, I'd just put in a Lithium instead.

Any value recommendations?

thanks

Russ Lyons [21030574] · Thu, 4 Apr 2002 18:09:35 -0500

Off hand, I think the current drain of those older memory chips would kill a lithium fairly quickly. I'm not sure the re-charging circuitry is "lithium compatible".

my 1/50th

Tom Moravansky [21030431] · Fri, 5 Apr 2002 03:46:33 -0800 (PST)

But I thought the standard batteries in there were just a pair of regular AA Duracells - not NiCads.

Russ Lyons [21030574] · Fri, 5 Apr 2002 22:41:49 -0500

Tom,

All three of the Chromas I have seen had Duracells in them. I think the re-charging circuit was designed with lead-acid batteries in mind. I'm not sure you can just hook up any other type of battery and have it work predictably and re-charge safely.

Tom Moravansky [21030431] · Mon, 8 Apr 2002 04:01:04 -0700 (PDT)

When you say re-charging circuit, you don't meanrechargeable NiCads, do you? You're talking about the RAM refresh, right?

The Duracells I pulle dout were not rechargeables

David Clarke [21030085++] · Mon, 08 Apr 2002 19:42:53 -0400

The service manual does discuss a bit of leakage back into the batteries when the main power is on (in terms of a 'trickle charge'); however, I'm not certain if the engineers really meant this to be some sort of battery charging circuit or not.

I keep regular alkaline batteries in all my units, all all seems well.

On another note - how did you make out with your Rev 14 EPROM upgrade?

Tom Moravansky [21030431] · Tue, 9 Apr 2002 03:34:26 -0700 (PDT)

I pulled the rev 14 EPROMs from Russ's board that he dropped off. They matched up exactly with the files on the web site. The chips I burned are in my friend Jeff's Chroma, and I haven't got them back yet to check.

So in summary, it looks like it's some mechanical problem on my end and the web site IC images for rev 14 are OK. If I have time this weekend I'll pop the rev 14's in my Chroma. If that works, I'll erase my rev 12's and reburn those as 14's and check them out too.

SoundDiver, Chroma and so on

Malte Rogacki [21010091] · Sat, 13 Apr 2002 22:06:17 +0200

Hello everybody;

as some of you might know I created the SoundDiver adaptation for the Chroma (a long time ago). In fact this was first adaptation at all! My own Chroma has been in the shop for a very long time now so I couldn't make any adjustments and changes. Maybe I'll get it back sometimes and as soon as I do I'll see what I can do. As far as the Chroma CC project goes: Of course I can do any changes to the adaptation (in fact, most everybody could). Actually I had been thinking about making a dedicated module sometimes that would reflect all those routings, too. But of course this will have to wait until I get my Chroma back. There's still some other stuff to do; see my separate mail.

Polaris, OS revisions and more

Malte Rogacki [21010091] · Sat, 13 Apr 2002 22:10:47 +0200

Here we go again:

After a *very* long time I finally got my Polaris back from repairs (and it's actually working this time!). So I started to do a SoundDiver adaptation for it (there were some requests). While the basic communication looks quite ok it doesn't really work at all. Sometimes I need to re-send a certain patch several times to get it "right" into the edit buffer. If I manually send the current instrument from the Polaris and capture it using a MIDI sequencer I'm experiencing the same problems. Which leads me to the conclusion that perhaps the OS revision is a insufficient. However I couldn't find any docs mentioning the final revision level. Any Polaris owners around that can check their revision? Mine is 05.

Malte Rogacki [21010091] · Sat, 13 Apr 2002 22:29:29 +0200

Polaris Revision Check

I forgot:

To check the Polaris' OS revision send it the following SysEx string (all Hex): 

F0 08 00 49 F7

It will return something like: 

F0 08 00 3D 30 33 30 35 22 50 6F 6C 61 72 69 73 22 F7

with the 7th and 8th byte forming the OS revision (in ASCII). Tidbid: The remaining part (22 50 6F 6C 61 72 69 73 22) is actually the name Polaris in quotes....

David Clarke [21030085++] · Sat, 13 Apr 2002 19:08:50 -0400

Polaris Posts (OS Revisions, incl. Chroma)

After a *very* long time I finally got my Polaris back from repairs (and it's actually working this time!). So I started to do a SoundDiver adaptation for it (there were some requests). While the basic communication looks quite ok it doesn't really work at all. ... Which leads me to the conclusion that perhaps the OS revision is a insufficient. However I couldn't find any docs mentioning the final revision level. Any Polaris owners around that can check their revision? Mine is 05.

To throw in an obligatory Chroma (non-Polaris) reference, the Chroma Computer Interface Manual does also cover the Polaris. In the Revision Information section it specifically calls out Rev 8 - so we know at least that verison existed.

To check the Polaris' OS revision send it the following SysEx string (all Hex): 

F0 08 00 49 F7

If you're not hooked up via midi at the time, you can also get the revision level from the keyboard itself. Just hit LF-D-2, and the flashing number LED will represent the version number.

Also, for the message above, the 3rd byte (00) is the midi channel of the Polaris.

It will return something like: 

F0 08 00 3D 30 33 30 35 22 50 6F 6C 61 72 69 73 22 F7

Just for interest, converting the other items (from hex to ascii, starting at 00) we have:

  • 3D = "="
  • 30 = "0"
  • 33 = "3"
  • 30 = "0"
  • 35 = "5"

The "03" is the instrument ID (03 = Polaris), and the "05" is the revision.

This output is the Midi equivalent of the what you'd get from a Chroma with the "Identification" op-code over the Chroma interface (1= Chroma, 2 = Chroma Expander, 3 = Polaris).

Malte, I have Rev 9. For some reason, I think it might have been the highest rev released.

I can send you the 4 object files for that version, if you like (the contents of Z10 - Z13).

Regards,

David Clarke

chroma and jlooper midi interface

Daniel Benoit [21030109] · Thu, 18 Apr 2002 23:54:36 -0400

Hi

first, this is my chroma:

  • Serial number:21030109
  • Rom version: rev12
  • kbdrom: rev2

Shape:

  • Average scratches on wood, top and trims.(7.5/10)
  • Switch panel; clean and scratchless
  • 1 voice board is missing cem33.. VCO and the termal resistors that goes with it.
  • Original legs
  • Original PSU
  • No pedal assembly
  • Left hand controls NOT original! They are from a minimoog left hand controle panel (pitch and modulation wheels)

I got the chroma 9 years ago as a trade for some work I had done on is Sequecial Circuit (Pro something...) and a ARP pro soloiste. It has been in my keyboard setup but not realy used since. I got all the manuals a the time and a JLcooper midi interface.

At this point, I would like to use the midi interface on the chroma, I have tried with a cable that does pin to pin connection from the db25 to db25 but got no results (in or out). Anyone knows what type of cable should be used and if there is something special to do to make this midi interface work with de chroma.

David in one of your posting I think you said that you would fix voiceboards for the price of part and shipping. Is this offer still standing...

Thanks
Daniel Benoit
from Montreal

David Clarke [21030085++] · Sat, 20 Apr 2002 13:21:48 -0400

Daniel - welcome to the list.

If you're connecting the JL Cooper interface (Chromaface) directly to the Chroma you'll need a straight-through (pin to pin) cable. The Chroma interface will use the majority of the pins - so you will need a 'complete' cable (i.e., some computer cables may only pin out some of the signals).

If the cable is OK, there are a few other things that may cause problems.

First, I would open the case of the unit and look at the settings on the 6-position DIP switch. Take a peek at the manual. This will confirm that you're set to the channel you believe you are.

If you're bringing the MIDI into a PC, I would suggest running a piece of software to watch all incoming MIDI information - something like MidiHack [formerly available from Techno Toys]. This will let you see if anything is coming out of the interface.

Now, power up the Chroma and power up the Chromaface.

On the Chroma, issue a "Set Split 17 command" and then hit a few keys. Check to see if you have any MIDI data on the PC.

If that fails, I would then start general troubleshooting to see what's good and what's not (i.e., confirm the MIDI cable is OK, confirm the PC can accept MIDI from another source, confirm that power is going to the Chromaface, etc.)

Good luck.

David in one of your posting I think you said that you would fix voiceboards for the price of part and shipping. Is this offer still standing...

Sure - you're just down the road in Montreal. Unfortunately, the parts you note as missing are probably among the most expensive on the board.

If you want to pursue this, just let me know and we can exchange e-mail (off of the list) regarding details.

Chroma For Sale on eBay

Chris Ryan [21030691] · Wed, 24 Apr 2002 15:15:29 -0700

With picture--looks clean. Currently US$1195 (no bids yet). Ends April 30.

"This is a beautiful Chroma, in excellent condition throughout, plays beautifully and comes with an anvil style flight case and the 2 pedal assemblies. It has the standard operation manual. Simply a great sounding synth, and in living room condition."

eBay item 861281764--here's a picture.