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Thread: Something Different - DECTalk DTC03

  1. #41
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    Congratulations! I am interested to see how your enclosure turns out. Glad to help.

    Lou

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    I recently (March) obtained one of the "70-22666-01 DTC03 DECTALK III 8-SLOT BACKPLANE" rackmount modules along with 6 50-16704-01 C5005 DTC-03 cards inside, and had two cards from previously, so I was able to completely fill the rack with all 8 cards.
    One piece of the rack is missing, the metal panel (with 16 rectangular holes in it, 2 lining up to each card) which goes in between the hinged magnetic door on the front and the front of the 8 cards. Perhaps someone has an extra lying around.

    The problem is the rack's power supply (70-23328-01, also called 30-31096-01 or DECTALK III POWER SUPPLY on some part sites), which makes a rather nasty arcing noise when powered on (with no load); it does seem to provide the correct voltages when measuring the pins with a meter.
    The power supply internally is just a PowerMate EVD-165-3001 caged bench supply mounted in a heavy DEC case. I'm suspecting bad capacitors at this point, since even though the caps are all Nippon Chemicon (old name for Nichicon), they are from 1985. Will investigate further.

    Based on the backplane (and not realizing Lou had done this already until halfway through) I traced out what all of the backplane pins connect to.
    https://docs.google.com/spreadsheets...it?usp=sharing

    Interestingly, one of the 6 cards which came in the backplane is clearly a prototype! It lacks the 23-xxx markings on the roms (though their contents match the earlier 23-114,115,116,117E6 code roms, along with the 23-028,029,032,033E6 dictionary roms, except for one single rom which may be going bad and has 6 bits flipped), and has a serial number of "DMT003" (DEC manufacturing test, maybe?). The pinout on that prototype card is slightly different from the later ones! It lacks the second 2 pairs of +5v pins and the second 2 pairs of GND pins, but otherwise matches. The TMS32010 DSP code PROMS also match 23-229,230F4 on the final cards.

    The backplane itself I have has the lower (used by the prototype) 5v and GND bus pins reinforced with an extra metal bus bar soldered behind each one in addition to the trace on the pcb itself, so perhaps this cage once held more prototype cards and required this as a retrofit due to excess current on just those two pins per rail per card.

    Jonathan Gevaryahu AKA Lord Nightmare

    P.S. does anyone know what version numbers the different rom sets correspond to? It should be possible through some <ESC>+something commands to make the dtc-03 speak its version number or return it in hex. (Without a working power supply I can't do that here right now)

    The only three romsets I know of so far for the DTC-03 are:
    (23-028,029,032,033E6 - dictionary, common to all dtc-03 versions I know of; internal datecode is 30 Oct 85)
    (23-229,230F4 - TMS32010 DSP code, common to all dtc-03 versions I know of)
    23-114,115,116,117E6 - oldest version I know of; internal datecode is 03 Dec 85
    23-305,306,307,308E6 - 'middle' version; internal datecode is 06 Apr 87
    23-425,426,427,428E6 - 'final' version; internal datecode is 03 Jan 89

    Are there any other versions anyone has in their DTC-03 cards?
    Last edited by Lord Nightmare; May 5th, 2015 at 05:31 PM. Reason: Add note at end asking about DTC-03 versions

  3. #43
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    Jonathan,

    Sounds like a very nice find. I would have to dig my DTC-03 out to check its roms. I don't think I noticed anything special about it. Someday I will dig it out again and check the roms.

    I would very, very much like to find a French TTS chipset for the DTC-03. I recently picked up the Parallax DECtalk v5.01 board for a song at a radioshack store that was closing. I was diasppointed it only did English and Spanish.

    Lou

    Quote Originally Posted by Lord Nightmare View Post

    The only three romsets I know of so far for the DTC-03 are:
    (23-028,029,032,033E6 - dictionary, common to all dtc-03 versions I know of; internal datecode is 30 Oct 85)
    (23-229,230F4 - TMS32010 DSP code, common to all dtc-03 versions I know of)
    23-114,115,116,117E6 - oldest version I know of; internal datecode is 03 Dec 85
    23-305,306,307,308E6 - 'middle' version; internal datecode is 06 Apr 87
    23-452,426,427,428E6 - 'final' version; internal datecode is 03 Jan 89

    Are there any other versions anyone has in their DTC-03 cards?

  4. #44
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    Three years ago I intended to check the roms in my DTC-03, but was only really motivated to do so today. I found another DTC-03 today for $5 from a favorite upstate NY surplus place (P&T in Kingston). My new one and my original one both have the 'final' version roms (as listed by Jonathan). My quest continues for both the service manual / FMPS and French language rom set ....

    Lou

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