Virus Ti Polar - Dead Keys

[ravecreator]

Hi, i´m new to this forum..
i have a problem with my Virus Ti Polar, i got 2 dead Keys on the Keyboard.
they seem to function ok, but give no tone anymore.

is there any chance to fix this myself? maybe i can open the virus
and try to clean the contacts? (i hope thats the problem)

how hard is it to open the virus polar and get to / remove the keys?
maybe someone can help or have pictures how to open a virus ti Polar?

many thanks in advance

[Timo]

Hi there, is the Polar under warranty? If so, that would be the first port of call. Reason being, you wouldn't want to void your warranty if you still have one.

Otherwise, if you feel able to take a look inside, there is a similar recent (ongoing) thread to your query with pics, etc.:

http://infekted.org/virus/showthread.php?t=33471

The pics are for a Virus Indigo, but I'd imagine the Polar would be quite similar. If or where it varies, you would have to use your intuition.

If the ribbon cable is inserted correctly, and you still have the problem, then it will likely be the key-contacts.

I, personally, haven't opened up a keybed yet to see what's inside (as I have had no need to), so unfortunately I don't have specific pics for doing that.

As a guess, after removing the keybed from the Polar, I think you would need to remove the black plastic cage underneath the keybed, before opening up the PCB that houses the key contacts.

The video on the thread I linked to above will show you how to clean the key contacts themselves.

It shouldn't be too hard I wouldn't think. But it will require due care not to damage the rubber key-contact strips (even though they would likely be very cheap to buy, even if you did so).

[ravecreator]

thanks for that info.. the virus dont have warranty!
i will have a try on that case this weekend..and report here

[KaareDK]

Hello... the link is dead! Could you please upload the instructions once again!?

Thank you very much :)

[Timo]

Hi, the link to the other thread?

http://infekted.org/virus/showthread.php?t=33471

Ah, seems like ChimneyChop had soft-deleted that support thread, most likely as he solved his query. Never realised he did this. I've undeleted it, as I feel the information is worth keeping for others.

However there's also a similar thread that's been posted recently:-

http://www.infekted.org/virus/showthread.php?t=34157

[unknown_artist]

Hello guys,

I had two dead keys on my Polar... after cleaning the board, one of the dead keys still do not work. I guess, it is needed to replace one pair of that small guys (resistor?). Could anyone confirm if I am wrong or right, please?

Otherwise I may need to exchange the whole board (Silga T120 C 94V0) I assume. But do not have any idea where to get it from.

Many thanks for any advice!

[Timo]

Hello guys,

I had two dead keys on my Polar... after cleaning the board, one of the dead keys still do not work. I guess, it is needed to replace one pair of that small guys (resistor?). Could anyone confirm if I am wrong or right, please?

Otherwise I may need to exchange the whole board (Silga T120 C 94V0) I assume. But do not have any idea where to get it from.

Many thanks for any advice!

Hi there, your problem could just be the silicone rubber strip that is worn out/torn/damaged, check this first:-

http://infekted.org/virus/showthread.php?p=306900#post306900

Check the contact on the silicone rubber strip corresponding to the key that is causing you the problems. Look for any tears, or whether the rubber foot for that contact fails to naturally pop back outwards - if the rubber contact stays depressed, or is torn, even slightly, the rubber contact strip for that octave is damaged and needs replacing. It can be easily and cheaply replaced (cost me around £6 per octave). I explain more in the above thread as I had the same problems (one key only transmitted a low velocity, and another key failed to work at all, despite cleaning all the contacts on both the PCB and the rubber strip) and was only identified by viewing the rubber strips closely for damage and obtaining new strips.

As my Indigo is/was approx. 18 years old (has it really been that long?!) I decided to replace all three octaves with three new rubber strips (2x 12-note strips, and 1x 13-note strip) at the same time. Again, more info is in the link above.

[unknown_artist]

Hi and thanks for your quick reply.

I did check and clean all the rubber contact strip; they all look just fine.

And I tried the to touch the contact by hand (see the photo), it just does not work. I forgot to say, there was a slight spot of coffee or coke.

[Timo]

Touching the contacts manually by hand may not be the best way to test it as it's probably more complex than just contacting the contacts individually. The contacts will be trying to calculate the velocity/speed from your 'press' between each of the two feet. I guess make sure you use an 'init' patch where velocity doesn't modulate anything, and I think for the key press to work you'd need both feet to cover all four of the PCB contacts, not just two of them, and to contact them in the correct order, and time/speed. I'm just guessing this, though.

PS> actually it would be easier to try taking off a rubber strip from one of your other octaves temporarily, fully install it into the 'faulty' PCB octave section and see if the key still doesn't work. This would ascertain whether it's the electronics/PCB or the rubber strip.

Other than that, you think it was directly caused by a coke/coffee spill? Coke/coffee have sugars and acid in them which can be pretty bad for PCBs.

Unless others chip in, I'm unsure what to advise further other than possibly contacting http://synthesizerservice.de for advice, who are Access' service guys, although they are based in Germany.

BTW, pretty sure those 'small guys' look like diodes of some sort, rather than resistors. You'd need to take a close look at them to see what type/variant they are. Sadly I'm no diode expert, unfort'.

[unknown_artist]

Touching the contacts manually by hand may not be the best way to test it as it's probably more complex than just contacting the contacts individually. The contacts will be trying to calculate the velocity/speed from your 'press' between each of the two feet. I guess make sure you use an 'init' patch where velocity doesn't modulate anything, and I think for the key press to work you'd need both feet to cover all four of the PCB contacts, not just two of them, and to contact them in the correct order, and time/speed. I'm just guessing this, though.

I did this with other contacts too, and it worked well except the faulty contact.

PS> actually it would be easier to try taking off a rubber strip from one of your other octaves temporarily, fully install it into the 'faulty' PCB octave section and see if the key still doesn't work. This would ascertain whether it's the electronics/PCB or the rubber strip.

Already tried this too. No change.

Unless others chip in, I'm unsure what to advise further other than possibly contacting http://synthesizerservice.de for advice, who are Access' service guys, although they are based in Germany.

Thank you, I'll call them tomorrow. I hope they are not going to ask €300 to fix the issue, its only 1 key. :rolleyes:

[orx65]

Hello guys,

I had two dead keys on my Polar... after cleaning the board, one of the dead keys still do not work. I guess, it is needed to replace one pair of that small guys (resistor?). Could anyone confirm if I am wrong or right, please?

Otherwise I may need to exchange the whole board (Silga T120 C 94V0) I assume. But do not have any idea where to get it from.

Many thanks for any advice!

hello
these is crystal diode (germanium) check the image probably all 4 with same measurement.. (i presume )
If you have multimeter , desolder all 4 select diode modality and make the measurement ..if 1 or more is with different value replace.

[unknown_artist]

thank you a lot for that information, orx65. you give me a hope. ;)

is it really necessary to desolder the diodes first before measuring them?

i did the measurement already - you can see the values on the picture i got from all the diodes (more or less same values).

do all diodes have to show the exact same value? or is it not a problem when one diode shows 0,619 and other one 0,625?

best regards

[orx65]

hi
yes for correct measurement is necessary desolder them as any other different electronic component..unfortunately i don't have schematic of this synth i know that a few difference can to be a normal tollerance anyway the correct value for germanium diode is 0,5 - 0,8 v ..do you want to be sure ? replace all 4 ..example link
http://www.ebay.it/itm/AA117-Diodo-al-Germanio-equivalente-OA85-AA118-AA132-AA134-OA161-2pezzi/112639946630?hash=item1a39dd2f86:g:MmsAAOSwEZdaCY1T

let me know , good luck

[unknown_artist]

Here's a photo of the 2nd board - in that board comes the signal from the contact PCB. Any ideas what component from this board could cause the dead key?

https://i.imgur.com/LOPZqow.jpg

[orx65]

i'll try to resolder all solder joint incoming from red connector , i realize that it is an empirical solution but considering that we do not have the schematic ...

[Michael Vilogi]

did you ever find fix? similar issue here

[Timo]

did you ever find fix? similar issue here

Have you tried this thread?:- Indigo ---------> 1 key not triggering <--------- (http://infekted.org/virus/showthread.php?t=33471)