PC88 problem with keys

[evad]

I have a PC88 that has a problem with the keys on the right side of the keyboard.

When you press the keys on the left side they play normally. When you press softly they play softly when you hit them in a stronger manner the sound is louder.

When you hit the keys on the right side no matter how softly or how hard they play the same volume.

Is this something that has to do with the programming or do you think something is broken?

Thanks

 

[happyrat1]

Does this affect only a particular setup or program or does it affect them all equally?

If it affects them all it could be something wonky in your global keymap settings or it could be a hardware failure.

One way to know for certain is to backup all of your user settings and programs and setups and then perform a factory reset.

If the problem persists after that then it is definitely some kind of hardware failure and you should contact Kurzweil support for further diagnostic info.

Gary

 

[Steve Jay]

Evad did you get your keys resolved. If not the problem is the contacts on each key. There are 2 on each key. One of them contacts slightly before the other. That is how the processor knows how fast or hard you have hit the key. If the first contact gets bad , (kind of like a old remote controll that you have to push harder to make it work.) It will usually be very loud. I had to replace my contacts for this very reason. I am on this forum because I am having some other problems with my PC88 . It changes voice selections randomly and I am trying to solve it. I think it is probably a bad logic board. The keys work good though

 

[happyrat1]

Steve >>> The problem with your voice selections is more likely a switching problem than a logic board problem.

Are the voices switching incrementally from one to the next or is it seemingly random jumping from bank to bank?

Either way, I'd suggest opening up the top panel and trying a squirt of contact cleaner into each bank and program select button just in case something sticky is fouling one or a few of them up.

If the switching is incremental it could also be the rotary encoder of the jog wheel that needs to be replaced.

As a last resort you might end up having to switch out the entire switching assembly board out for the guilty one be it the numbers keys, the bank or program select boards or even the encoder wheel.

See if contact cleaner improves the situation first though.

Gary

 

[Steve Jay]

The only thing that is random is knowing when it is going to change. It always goes directly to Piano & Strings. Do you know how when it first starts up it will always default to the first piano button. It has gotten so bad that it goes to the first piano like normal and within 1 second it jumps directly to Piano & Strings or that same button if you shut it off like on acoust and strings. I have had this keyboard for almost 10yrs and it has been a work horse. I have had the board out years ago when I first got it to repair some bad solder joints on the chorus buttons. I have the board out again and have cleaned it and also checked the buttons to make sure they have no continuity. I really think it is a bad chip because when it is working you can bang on it real hard and it is totally unaffected but it can be just sitting there without touching it and you can watch it change. I don't think it is the jog wheel because it works and it always goes in succession. My daughter plays it in our worship band at church and she started complaining about it a month ago and I thought she was nuts

 

[happyrat1]

Transistor logic is incredibly stable. Generally speaking, it either works or it doesn't.

After 10 years of heavy road use though, the bank select and program select buttons have taken a pounding.

I'm not certain about the PC88, but judging by the action on my PC3K the control switches are all of the spring dome type.

These are metallic domes made out of a spring-like phosphor bronze material that eventually fatigues and either cracks or collapses and can result in intermittent and unpredictable contacts.

The good thing, in your case, is that it probably is the Bank 1 or Bank 2 switches that need to be replaced.

I'd suggest phoning up these guys during business hours and see what they suggest you try first before swapping out an expensive logic board.

http://www.instrumentalparts.com/kurzweil-parts.html

Chances are they could sell you an entire bank switch assembly for less than Kurzweil could.

Also if you really want to be thorough, open it up, disconnect the bank switch ribbon connector, take an ohmmeter and test each switch with vibration and simple tapping and see if any of them give you jumpy readings.

If you're good with a soldering iron and can lay your hands on an exact replacement, simply replace the guilty switches. Otherwise, though I'd say just replace the switch PCB assembly.

Gary

 

[Steve Jay]

Gary you got it! I decided to do a higher resistance check on the switches. I had 1500 ohms yet when I pushed the switch only wiggling and hard would it go lower. I wasn't sure if the the resistance was in the switch or in the circuit so I removed it. It is working now and the switch out of the circuit is not showing any resistance either which is weird but it is definitely the problem THANKS.. I will contact that place you sent a link to and get some new switches to replace the bad one and some others that you have to push really hard.
I want to update keyboard but I couldn't sell this one broke. I am looking at the Yamaha MOXF88 and the Korg Krome

 

[happyrat1]

Glad I could be of help Steve.

If you need to update, the PC88 would still make a kickass controller for a hardware rack module like a Peavy Musebox or a Roland Integra or a used Yamaha Motif Rack, plus you'd get to keep the amazing VAST sound engine as well.

Personally I don't think I'll ever sell my PC3K8. If anything I'll just keep adding modules whenever I feel the need for something new.

Take care,

Gary

 

[Steve Jay]

Which modules would you recommend that have best acoustic piano sound and a good hammond organ with controllable leslie. The onboard leslie effect on my Kurzweill is pretty lame

 

[happyrat1]

For a decent Leslie effect pretty much everyone recommends the Neo Ventilator. As for which modules, it depends on your budget.

Anything is an improvement starting from the Ketron SD series up to the Peavey Musebox or the Muse Receptor if you can afford it, or a current Yamaha Motif Rack or the Roland Integra if you have money to burn.

I'd suggest visiting the manufacturer's websites and youtube and giving them all a listen while googling for a few user reviews on anything that catches your eye.

Gary,

 

[richardbruce]

Which modules would you recommend that have best acoustic piano sound and a good hammond organ with controllable leslie. The onboard leslie effect on my Kurzweill is pretty lame

Check out the E-mu B3 module best Hammond sound for the $ I've ever heard.

 

[Sam Miskell]

Evad did you get your keys resolved. If not the problem is the contacts on each key. There are 2 on each key. One of them contacts slightly before the other. That is how the processor knows how fast or hard you have hit the key. If the first contact gets bad , (kind of like a old remote controll that you have to push harder to make it work.) It will usually be very loud. I had to replace my contacts for this very reason. I am on this forum because I am having some other problems with my PC88 . It changes voice selections randomly and I am trying to solve it. I think it is probably a bad logic board. The keys work good though

I have the same problem. I took it apart and clean it but I think the circuit board under the rubber pad is bad. What do I need to do when the first contact gets bad.

 

[Ladislav1984]

I have a PC88 that has a problem with the keys on the right side of the keyboard.

When you press the keys on the left side they play normally. When you press softly they play softly when you hit them in a stronger manner the sound is louder.

When you hit the keys on the right side no matter how softly or how hard they play the same volume.

Is this something that has to do with the programming or do you think something is broken?

Thanks

 

[Ladislav1984]

Please help me with this problem any body who understands thank you so much Kurzweil pc88 all working just the Problem not listening sounds Playing speaker