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

  • Issue come back once since, with different patch, playing a single note. However this time I was using it only as MIDI keyboard, then I noticed the BPM and LFO LEDs blinking frantically so I plugged it headphones.
    The sound was pure horror, I switched it off rather than recorded it. I made backup via sound diver and want to factory restore, but since I have also learned how to import patches with SD I had to postpone the restore...
    Because the sounds you can get....


    Hey Cloudswim, I sent you PM, did you get your issue resolved?


  • please contact support by email
    thanks! marc

    As many, many others I have similar problems with my Virus C as described in this thread.


    When I try to contact Access Music and the repair service center they refer to, I receive no response, no help. I have tried for months now.


    The problem with the Virus C discussed in this thread seems to be a very common one unfortunately.

    I've had my perfectly working Virus C stored in a closet in its original box for about 15 years, and when I set it up again for a while ago, it only worked for about half an hour. Then there was some loud noises from the synth, crackles and so forth and it froze. Restart didn't help much. After many tries I eventually got it to work again, especially when trying to write to memory.


    But now it's completely hopeless.

    It starts up, very slowly, and some menu functions work (not all) but then it freezes, especially if I select multi mode patches.

    I also get the "Error Number 2, DSP-RAM failed !" error message sometimes when I try to write to memory or reset the synth to default settings.

    There's no sound from it at all now.



    Most of the capacitors are replaced with new ones = no difference.


    I don't know what to do any more and I receive no help from Access Music or the german repair service center they refer to.


    I bought this synth new for quite some money back in 2003 and it is barely used at all. I can't understand why Access Music cannot help its customers when their own product is malfunctioning for their customers?

    It seems to be quite risky to buy Access products, if there's no help when problems occurs.


    Any help, PLEASE?

  • Hi all,


    I have the same problem as many of you :(


    I tried everything: changed the battery, changed the PSU with a new official one, upgrade, downgrade, i took it to an authorized service (no Access, cause we don't have it here).. My Virus simply works fine.. until it stops working, with the same symptoms that many have experienced here.


    Next, I'll try to clear all banks with default patches. I know this is silly, but I have read that someone has tried to work with only certain banks and had no problems.


    Maybe someone has got an update? I don't want to put my Virus to bed, especially because when it works.. it still works like a charm.

  • I don't think it's an issue with the Flash, so doing a factory reset, firmware update or clearing preset banks most likely won't change anything. I'd suspect it to be an issue with either the voltage regulation, faulty memory or the DSP itself. https://www.norduserforum.com/…ot-t20997-30.html#p143872 is an example of memory failing in a Clavia Nord Lead 3 which uses the same DSP architecture, so such a failure mode isn't entirely unthinkable.

    Swapping the memory ICs out for replacement is also quite doable for someone with a hot air gun and some SMD experience - like a good phone repair shop.


    http://studiorepair.com/galler…_11061601_1106213807.html shows the PCB - the voltage regulators on the left, the three RAM ICs between the voltage regulator and the DSP.


    One of the voltage regulators is a switching voltage regulator which can wear out the capacitors that are part of that circuit. Replacing these would be my first course of action (like here: https://erichizdepski.wordpres…17/access-virus-b-repair/ ). My second course of action would be to replace the 7805 voltage regulator with the heat sink - who knows what wear it suffered from the heat and it's cheap anyway. If the problem persists, I'd replace the three RAM ICs. Then the DSP or the audio codecs, depending on what's cheaper to obtain.


    One can of course send it also to a synth repair shop but who knows what they'll charge.

  • I have had my indigo 2 since when they were new. In 2018 after being storage it needed a new battery and had some crackling in the audio.


    I contacted access who responded saying they hadn't heard if this issue and no longer had parts. I took to an official access repairer who said the main board needed replacement and no longer available and offered to dispose of the virus for free.


    I took it to another repairer. Who had for a few years but was unable to find issue. I found someone online that had fixed 5 with similar issues to mine and was sure it was the dsp. When I got the virus back after pandemic it was real bad. Harsh noises and sounded terrible. A replacement dsp was acquired and was replaced by a friend.


    The virus now works with clean audio but after about 30 minutes audio cuts out. If this is ever fixed I'll post about that too. From my years of research and dealing with this. Serious problems with virus c are the dsp failing or the ram.


    Even when mine was at its worst it never had issues with the os or anything it was always the audio.


    Hope that helps brings some virus c back to life.

  • > 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.

  • > 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.

    Other account got deactivated, mines an indigo 2 so it has an laptop style power supply mounted in the case which connects to a barrel connector on the side of the pcb. I would assume it is the same spec as the desktop units 2.5mm barrel centre positive 12v 2a, but never found any info about it.

    I ran mine for 80 mins yesterday with the side plates off and fan blowing through it without issue. Does nothing in the virus use 12v? (also note I have a keyboard version)

  • I'm really not sure why Access decided to use such a small heat sink for the linear 5V regulator, it certainly reduces its life span.

    The NE5532 amplifiers in the audio output stage do use the 12V supply but with a 9V power supply they still receive more than enough voltage to be within nominal operating range, so a 9V supply works just fine.


    If you want to keep using the internal 12V supply, you could have someone add a 4.7 Ohm, 5W resistor in line with the power switch. That switch only switches the 12V, so there's no dangerous voltage going through it. The resistor would drop the main board voltage from 12V to about 9.5V while warming up a little. Essentially, it generates some heat that otherwise would be generated by the linear 5V regulator.


    Alternatively, the 5V regulator could also be replaced but that's a little more involved since the heat sink is soldered to the board as well as mounted using sticky tape.