Posts by abraxa

  • Access Virus C audio dropouts and harsh noises - always needs re-starting

    > after about 30 minutes audio cuts out


    That should be the 5V linear regulator on the heatsink. When the thermal shutdown kicks in or it's broken, the reduced output voltage makes the audio circuitry stop working while the DSP still runs fine as it's not running off of that regulator. The heatsink is sized inappropriately, so in my Virus the voltage regulator broke eventually. For yours, it may be the heat triggering the thermal shut down after 30 minutes.


    If you use a power supply with a lower output voltage (9V instead of 12V), I would assume that the Virus should run longer or not have any issues anymore at all. Just gotta make sure it can deliver 1A and that the plug polarity is correct.

  • MIDI CC/PC messages to switch to multi mode & select a multi? SOLVED!

    Just for reference:


    Virus TI - SysEx - The SysEx pages have changed compared to Virus A/B/C.


    https://www.musiker-board.de/t…ysex-bei-virus-ti.317840/ shows the response from Access on how to switch between modes via SysEx on the TI:


    f0 00 20 33 01 10 73 40 7a 00 f7 switches to single mode

    f0 00 20 33 01 10 73 40 7a 01 f7 switches to sequencer mode

    f0 00 20 33 01 10 73 40 7a 02 f7 switches to multi mode


    73 is page D btw, for Virus A/B/C it was 72 for page C. The rest of the SysEx command is the same.


    Tested the command with SendMIDI and it works as expected:

    sendmidi dev "Virus TI Synth" hex syx 00 20 33 01 10 73 40 7a 01

  • Virus Ti desktop won't start up

    Did you try another power supply?

    If you hold the arp edit button while powering up the Virus, it'll perform a factory reset. I'm not sure if your user patches are preserved or not, so I hope you have them saved. If you're afraid of losing patches, don't do that just yet.


    If it doesn't boot up after the factory reset, you can put it in firmware update mode and reload the firmware that way. You do that by holding exit while powering up. The Virus control center should then be able to find it and allow you to reload the firmware. While I don't suspect this to solve the issue, you can try this as a last resort. I would suspect a hardware issue however, so try another power supply first.

  • Virus Ti desktop won't start up

    Can you try a different power supply? 9 or 12V, at least 1A, plug with + inside and - outside.


    Also, can you bring up the version information? You can unplug the Virus TI power supply, then hold TAP and CONFIG while plugging it back in. You should then see the serial number.

  • Some findings regarding DSP crashes

    Note: I desoldered the original DSP and soldered in a new DSP - the Virus worked flawlessly again. Since I'm curious like that, I soldered the original DSP back in again to verify. The Virus also worked flawlessly again, much to my surprise. This leaves me to assume that there must've been a cracked solder joint on one of the DSP's legs, as unlikely as it seems. It does somewhat explain though why the crashes didn't immediately occur when the Virus had been off for a while. Not a single crash so far, let's see how it goes. Should the crashes return I'll put the new DSP in again but so far it doesn't appear to be necessary.

  • Virus B button corruption

    > Seems something weird going on there


    Indeed. I'd expect a hardware fault to either be always present or temperature-related, not appear in different modes of the device.


    > all the Multi presets have strange names like ‘U*U**L*H*’


    Maybe the battery that was placed in the Virus isn't fully fresh and has aged in the packaging? I'd try a new one cause that's SRAM corruption for sure.

  • Virus B button corruption

    Unfortunately, I'm in Germany and not Ireland, so I can't recommend anyone in your area. If you search around but can't find anyone to do it for you, I'll see what I can do if you're willing to ship.

  • Virus B button corruption

    > Not sure what that means?


    It means the programs running on the Virus DSP and support MCU are working just fine - it's just the circuit for checking the button state that's broken - a hardware fault, likely on the user interface PCB, not the main PCB. Do you have a place that can check it out for you?

  • Virus B button corruption

    Since this is an issue with the internal multiplexing of the switches, I'd say that a part of the multiplexing circuit isn't working properly anymore. Could be one of the ICs used on the user interface PCB.


    It could also be a simple contact problem with the connectors, so re-seating the flat ribbon connectors is a worthwhile thing to try.

  • Virus TI no Audio

    > It sometimes crash or not boot up properly.


    The voltage regulator that you marked with 2V is a 3.3V regulator (SPX1117 in TO-252 packaging), meaning the pin where the white line ends is ADJ/GND and not the output. 2V would make sense for the adjustable version since that would produce a 3.25V output but if it's not the adjustable output version, this pin should show 0V. It would be interesting to know what voltage the right-side pin (input) and the base plate (output) show.


    The other voltage regulator in the same packaging is an MC33269 (marking 269AJ) with two resistors configuring it for 1.8V output. Hence, the base plate should show this voltage. Since the voltage on the ADJ pin is Vout-1.25V, the 0.5V you give is actually correct, so we know that the 1.8V rail is at least working.


    My first course of action would be to try a different external power supply (9-12V, - outside/+ inside) and if that doesn't help, the internal power supply needs to be examined more closely. I'd assume the 3.3V rail isn't working as intended, for example because one or more of the SMD capacitors are faulty and can't keep the voltage stable reliably.