Virus b problems - OS won't boot, LCD glitches, LFO led's light up - common problem

[tom_ch]

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!

[Schwar]

Do you know the name of the guy from Ebay?

[dxt178]

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!

[Rio]

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

[Timo]

Yep, more info:- http://infekted.org/virus/showthread...917#post305917

[tttt]

Is this repair something that's suitable for someone with little soldering experience?

I've got a Virus Indigo exhibiting these symptoms, while my first thought was to get it serviced, I'd actually quite like to learn the basics of this stuff so wouldn't mind trying to fix it myself (I got it cheap enough that I could live with myself, just, if I totally broke it 😂)

It sounds like it is fairly straightforward, but whenever I've tried fixing stuff before it's always turned out to be more complicated than I expected! Should I just need a basic soldering iron? Could I get an old/dummy circuit board to try it out on with a spare capacitor? Do I need to be particularly worried about discharge from the capacitor injuring me or should it be OK if I leave it unplugged for a day or two?

Any pointers gratefully appreciated (and if you don't think it's really suitable for an unexperienced solderer please say!)

[Timo]

I'd imagine Youtube would be useful for soldering tuts. Practicing on an old/dummy circuit board would be very useful beforehand.

You'll be pleased to know that desoldering a cap[acitor] is much easier than a pot[entiometer] - A cap only has two straight legs to desolder and pull out, whereas a pot has six and they're all bulky and kinked!

Kit you'll likely need:
* Low-wattage soldering iron, with a fine tip
* Soldering iron stand (to rest the iron while it's heating up)
* Wet sponge/paper for cleaning the iron (of any old globules) before tinning the iron tip
* New capacitors of the correct specification
* Solder (not too bulky/thick) with flux
* Solder-sucker (to remove molten solder when you're de-soldering the old cap out)
* Wire cutters or similar, to trim the capacitor legs to length after soldering them in.

Low-wattage soldering iron, 15 Watts or so, is useful to avoid burning things. A fine-tip on the iron allows you to work with greater precision, some tips (sold as default) are a little big and bulky and unsuited to circuit board work.

If you take the ribbon cables out of the main board to separate the chassis away from the front panel, make sure you remember which ribbon cable goes to which socket as there are three ribbon cables and they all look identical.

[tttt]

Thanks Timo, very helpful advice! I’m going to give it a go - a while ago I bought an 8x8x8 LED cube kit, so I need the equipment anyway if I’m ever to build that... I think I’ll use that as a practice project then move on to the synth Would be a handy skill to have!

[Timo]

8x8x8 cube? Straight in the deep end there. Would be more difficult I think as you're effectively soldering the LEDs in mid-air. Soldering a cap into a circuit board is easier as both legs are effectively tethered.