Casio WK-3100

[Colci]

I have a WK-3100 of which I am very fond. It fell off a trolley on the way to a gig and now makes a distorted crunching sound, when you press the keys. I've taken it to the repair shop you said it was beyond economic repair, due to the time required to locate the fault. I have opened it up. There is nothing inside evidently broken. It's midi functions are normal. Before I put it out of its misery and chop it up for repairs I thought I would try asking around if anyone has had the same issue.

I've posted a video of it here.

Thanks for any ideas,

 

[happyrat1]

It seems to be an audio or a DSP problem.

Since you've opened it up and found nothing obvious it's time to look for more subtle defects.

Something like a loose solder bead causing a short circuit somewhere or a cold solder joint where a lead appears to be intact but actually is fractured.

The logic and tonality of the board seems to be intact from what I can tell from your video so the audio is where I'd focus. Possibly a damaged potentiometer or slider from the fall or a bent pin resulting in a short circuit.

If it were mine I'd be taking the thing apart and looking at the solder joints with a magnifying glass.

I'd also be giving the pots a good work over just in case something is stuck inside of one.

How does it sound thru headphones? Have you tried yet?

Gary

 

[Biggles]

Welcome

Sorry to read about your problem.

If you are unlucky in your repair then perhaps its time for a new Casio CT X3000/5000

 

[happyrat1]

The WK series are 76 key models.

I doubt he'd be happy with a 61 key CT-X...

Gary

 

[Biggles]

The WK series are 76 key models.

I doubt he'd be happy with a 61 key CT-X...

Gary

Learn something new every day.

Just looked the WK 7600 at $450 has great reviews

 

[happyrat1]

Personally if I were he I'd wait until January's Winter NAMM to see if Casio plans to release any new WK-X models with 76 keys.

Gary

 

[Colci]

Thank you both. I'll definitely follow Gary's excellent advice and take my time with a magnifying glass. Through the headphones it sounds exactly like the way it comes out of the speakers. There are only two pots - main volume and mic volume, and I will start from them. But I'm glad the feeling is that it is something physical/mechanical and not a dodgy chip.
I shall also begin reviewing the alternatives. I am not so sure that having fewer keys is such a problem, but need to ask the other people who play it - its been a bit of stalwart jam session keyboard over the years.
The offering out there, not just from Casio, is vast and bewildering - and the technology - both in terms of connectivity as well as accompaniment functions have moved on so much in these ten years or so.

 

[happyrat1]

One thing to check is if the problem exists on both the left and right channels or only on one. This would narrow it down even more.

If the problem does end up being a blown chip or transistor and beyond your capabilities to repair I'd suggest replacing it with a Roland Juno DS76.

A little spendier than a Casio but light years superior to them in sound.

Gary

 

[Biggles]

Another option if your group of users can live with 61 keys and you and they use the Arranger features on your Casio is to check out the Arranger keyboards on the market.

If you look at the Korg channel on Youtube specifically for their PA 700 there are a number of their video tutorials on using this keyboard. Looking at some of the videos will give you an idea of just how the features of this type of keyboard have moved on in 10 years.

 

[happyrat1]

BTW, try first of all to pick it up with the power unplugged and give it a good shake in every direction and see if anything rattles or is loose inside.

That might give a clue and possibly even a quick fix.

Also try carefully unplugging and CAREFULLY replugging in all the connectors and see if anything is broken there.

THEN pull out the magnifying glass and examine it joint by joint.

Focus on the audio sections first. Those will be the boards with the driver transistors and op amps and heat sinks with output cables leading to the speakers.

Also check to see if any socketed chips have come loose from the fall. Press them firmly into place even if they look OK.

After all this try reassembling and powering up. See if this fixes the problem.

If not that's pretty much the extent of what you can do without proper test gear and procedures.

https://www.youtube.com/results?search_query=fixing+a+distorted+audio+circuit

https://www.youtube.com/results?search_query=fixing+a+distorted+audio+circuit+casio+keyboard

Lots of good advice on how to repair audio circuits there.

Gary