Nord User Forum

[lamickman]

Last night at a rehearsal my Stage 2 EX compact (73-key) had one key that stopped working; it's the Ab an octave and a half above middle C. No sound on this key no matter which program I choose.

I followed the instructions in the pdf on this forum for opening the unit and cleaning the contacts. I was very meticulous...but, when I put it all back together and turned it on, I saw a display in the LCD screen that I'd never seen before – then the power went off.

Turns out the fuse blew, so I bought some exact replacements at the local electronics store, put in a new fuse, and it also blew. I then took the unit apart again and double-checked everything, put it back together, and tried again – the 3rd fuse blew.

I'm at my wit's end – and I have three gigs in a row this week, starting tomorrow. Does anyone have any suggestions...please?

I've uploaded a pic of the LCD screen display that appears before the fuse blows; I've never seen this screen before.

Thanks in advance...

LAMickman

[pterm]

Yikes.
I believe you have a short circuit. Do not power up again until you think you found it.
A likely cause is an improperly seated or oriented connector. --But you double-checked already so:

Take care to always touch the metal chassis before touching circuit boards to discharge any static electricity.

Look for any stray metal that might have rolled under or onto circuit boards (missing any screws, washers or springs?)

If you have an ohm meter and can locate the power rails (+12V, -12V, 5V, 3.3V -- I don't have NS2 schematics, so just guessing), I expect you to measure 250-3000 Ohms between each rail and ground. If you see less than 100 ohms on one of the rails this might help you isolate the location of the short to components on that rail. (+/-12 are audio amplifiers, I believe +5V is audio pre-amp, LEDs, and USB, +3.3V is digital processors). --If this is beyond your knowledge, seek technical help.

I expect that screen message will tell Pablo exactly where to look, but until he answers I hope my suggestions help.

[lamickman]

Thanks so much for the quick reply! Yes, my first guess was a loose or misplaced connector, so even though I had been meticulous, I took it apart again. I found nothing out of place compared to the pictures I took before beginning the first disassembly. Also, there wasn't even the tiniest spec of any foreign material. All parts are present and accounted for.

I have an ohmmeter and am conversant with the procedures you describe (thanks for that!) but at this point I'm a little spooked about the whole thing - I opened it up, closed it, and it started blowing fuses. It could be that I inadvertently broke something or caused a short (I checked for crimped cables - none) or it could be a coincidental component failure...I know it's a long shot, but my fingers are crossed that Pablo may have an insight or two.

Whatever's wrong, I'll have to rent a board to cover myself for the week. Also, I need to find a reliable Nord repairman in Los Angeles, CA. Do you have any ideas how I might find such a person?

Many thanks for your kind assistance!

LAMickman

[pablomastodon]

Fuses generally do not blow for no reason -- one blown fuse may be a fluke, but when you blow 2-3 in rapid succession, pterm's advice kicks in: DO NOT power up the instrument until the source of this fault is discovered and corrected.

The display indicates that the instrument is booting to Test Mode. This will happen automatically if/when there is no OS. In your case, it appears that the OS was blown out somehow, very possibly by static electricity discharge as also mentioned by pterm.

The optimal time to call Pablo was BEFORE you opened the instrument. I would be interested to know what .pdf you were referring to for instructions on this operation. There is much bad info out there. I have walked people through that operation over the phone about 400 times in the past 6-1/2 years with a 0.00% failure rate, almost all on SW actions. A couple years ago I stopped doing this over the phone on HA/HP actions because they are slightly more difficult; I prefer to refer those cases.

I know you said that you double-checked cable connections, but perhaps it would be worthwhile to disconnect cables and closely inspect pins to ensure nothing is bent and shorted and/or that there is no conductive foreign matter inside a socket shorting pins.

Lastly, if there is any intermittent behavior to failing notes -- like if you can get it to play once out of twenty hits, then contamination of contacts is definitely the issue. However, if it is completely dead with no intermittency about it, there is the additional possibility of a blown/cracked diode on the contact PCB.

[lamickman]

This is the pdf to which I was referring, from user Marc:

nord-stage-forum-f3/help-key-stuck-at-full-velocity-on-stage-ex73-t3617.html#p22246

I also watched this video:

https://www.youtube.com/watch?v=rDMquHADdZ8

and printed out and heeded Pablo's notes:

post28370.html?hilit=dead%20key#p28370

I rechecked all connections. All pins are straight and no matter of any sort was found. The interior of the unit was very clean; it's only about a year old, and I always keep it in its case.

LAMickman

[simonkeys]

Also, Pablo, correct me if I'm wrong, but I thought that a symptom of dirt in the key contacts was that the key would work on organ sounds but not on piano sounds. If it wasn't working on any program, maybe the problem was elsewhere?

[pablomastodon]

lamickman,

that .pdf looks okay up to the point where he removes the keybed prior to disconnecting it and chooses to disconnect the keybed cables from beneath the keybed assembly rather than disconnecting those same cables from the mainboard end and then removing the keybed after. Really bad advice in my view and NOT the way the author of that .pdf and I did it together over the phone. I have no clue why I chose to show it differently here... I should add that I cannot imagine that this variation has anything to do with your current problems. Your best alternative will be to seek pro assistance

simonkeys,

that stated symptom is only one of a few possibilities, not the only one. And if you reread the final paragraph of my above post, you'll see that I mentioned the additional possibility of blown/cracked diode. In nearly 400 cases of this which I have personally handled, bad diodes were encountered exactly twice. It is very, very rare, but a possibility in cases where there is no intermittent aspect to the key's behavior, but if there is any intermittency, it will not be the diode.

bless, pablo