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Thread: CoCo3 cassette interface frustrations

  1. #1

    Default CoCo3 cassette interface frustrations

    I recently soldered together a makeshift cassette cable for my Coco 3s; for parts I used a solder-cup 5 pin DIN connector and a 3.5mm stereo audio cable cut in half. In making the cable I connected the "ground", IE, the lowest part of the stereo 3.5MM plugs to the center pin on the DIN (#2) and the "tips" to the flanking pins #4 and #5 for data in/out respectively. In other words, I followed the pinouts here:

    except since I used stereo plugs I left the middle "ring" contact disconnected. (Figured since most audio equipment these days is stereo there was no point seeking out mono 3.5mm phono plugs which would short right-audio to ground on most of the things I'd be likely to plug into them.)

    The cable seems to work, in the sense that if I set up an audio recorder like Audacity, type in a short BASIC program and record it with CSAVE to a Mono audio file what gets recorded certainly sounds like TRS-80 cassette data. Also, if I type "AUDIO ON" before typing CLOAD I can hear the audio plain as day through the TV speaker as the system tries to load the data, but I have had *zero* luck actually loading anything. Playing with the volume controls if I have the audio cranked up enough I can see the "S" in the upper left of the screen flicker from regular to reverse video, but... at one level it flickers but never completes loading, and cranked up just a tiny bit louder it always quits with an "I/O ERROR". I've tried converting some emulator .cas files to .WAVs and likewise have had no luck with them. (It's either "hang forever" or "I/O ERROR", never anything else. Literally it's one volume tick between the two.)

    I assume someone here has gotten this to work, what's your setup? I was using a Mac laptop when I was fooling with this, and I'm wondering if it's possible that CoreAudio is "cleverly" doing some equalization or something that's fouling up playback for the TRS-80. Alternatively, I'm wondering if it's possible there's some analog components like capacitors that are in the TRS-80's input circuitry that might have aged badly and are affecting cassette input? It's clearly not entirely deaf, hopefully it's something repairable.

    I'm going to try to scrape up a genuine tape recorder that works well enough to try this with, but unfortunately that's been turning out to be a surprisingly tall order. Any suggestions are welcome.

  2. #2
    Join Date
    Apr 2005
    Stevens Point, Wisconsin


    Try connecting the middle ring to tip. (Not ground or hanging)

  3. #3


    You can also try to use mono plugs-or a stereo to mono plug.Commercial programs loading is done with the CLOADM command-and not with CLOAD (but I think that you already know that).Maybe the problem is related to the sound output from your Mac.I have succesfully load in the past programs from my ASUS eee pc 900 to the coco using the stock windows media player in win xp.


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