Hi,
just to say I had the exact same problem - Virus B would keep 'cycling' during the boot, constantly resetting until eventually after about 20 minutes or so it would work fine.
I replaced the electrolytics and 2 of the voltage regulator (found and replaced the dodgy capacitor before I got to the 3rd voltage regulator) and it now works perfectly.
This thread is the only useful information about the problem I've found on the net - and it does fix it.
Just note that the capacitors marked 47uf-25v on the circuit diagram are 470uf-25v on the board - not really an issue as you spot it quick enough.

Huge thanks to audioman for posting up the fix and diagram

Help
 

My Virus B is doing exactly this thing!! Is there anyone near Southampton, UK, who could apply the fix mentioned in this thread? It's beyond me.

Just wanted to say thanks.

A friend's Indigo had the same problem, I replaced the two 220 uF and 100uF for the switching reg (LM2575T-5) and now all is fine!

Thanks Z. This is exactly what my Rack was doing, and exactly the fix for it.

~ vonnor

So mine receives midi and sends. It turns on but doesn't boot the OS. You can do reboots of the system but no sound comes out any of the audio outputs. I can send the most recent OS but once it asks you to store it. DSP-RAM error.
I replaced the one capacitor pointed out and it didn't fix it. I took down any oxidization that may have accumulated on the socketed chips(which I believe are the ram chips?)
Nothing looks unusual inside.
The LCD doesn't blink when it's turned on. It will often show black bars. All leds seem to still function and controls? unless you do factory restore in which it will show all sorts of internal saved information and let you go through all the menus...
Does anyone know:
Can I send the OS upgrade from a virus a?

Help!!

Confirmed, seems this is a common(ish) fault with the virus b - the capacitors go bad. Symptoms are part boot/ no boot, screen flickers green, LFO leds light up but nothing else. Don't despair, replacing the capacitors fixes the problem! There's a schematic in this thread, so if you take note of the cap values you can source them and replace without the need for a service manual. There's another approach - If you're like me and have no clue how to do that, there's a guy on ebay who sells a replacement kit that's not just a fix, but actually offers super audio quality to the existing design. It's really not that hard to do - my virus was a brick in the cupboard for three years but now it's actually better than it was brand new! Not an electronics wiz, but if I can do it....

Do you know the name of the guy from Ebay?

I recently purchased a Virus B that is in exceptional condition (like new cosmetically and mechanically) but occasionally while playing the display will begin to fill up with "1"s and then "@" symbols "P"s and other random characters. When this happens the unit continues to play perfectly and I can even change patches and adjust settings but the display only shows garbage characters. All LEDs, functions, etc. continue to work perfectly. Even the LCD technically works perfectly as far as brightness and display of characters just not the right ones.

Should I do a reset? Should I reflash? Could this be capacitor/psu? Is this something more serious? Should I cry? :) I'm capable at EE/soldering.

It is running 4.9 OS and right now I am controlling it from a Casio CTK-451 via MIDI on channel 1. I thought the "1"s may have been control from the Casio or some issue with the crappy Casio I am using currently. (Still could be, but I don't have any other 5 pin MIDI keyboards to test) TIA!

Hi,

Pre: yes i know - old post, but i think it's still relevant. Especially with regard to aging.

Which cap types are taken for replacement (e.g. Panasonic FC, FM or FR for max.temp 105° ones) - regarding lifetime, temperature and audio quality?

@Audioman: are you sure the caps are 47uF and not 470uf? I have took a look on my board, where there is a 470uF print on the related caps (as chancanasta has mentioned too). And the 4,7uF (M2A) is labeled with 63V...

Best regards,
Rio

Hey Fabio,
I had same exact problem but as OP and after a while of it just sitting it no longer boots at all. Dim screen with no characters and just the LFO 1 and 2 lights come on solid. I opened it up and replaced two 2w 1 ohm 10% tolerance resistor that had some charring on their bodies with a 2w 1 ohm 5% resistor (all I could find) and its still same thing. Dim screen, just thw two LESs. None of my other capacitors or resistors look bad but it sounds like I'd need to replace them as well. Question is, on your diagram, which caps did you replace? All of them or just some? Any clarification is appreciated. So bummed that this thing is bricked after
15 years of just sitting on my desk and working without fail in my studio. :confused: