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Thread: Problems with KURZWEIL PC2x

  1. #1
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    Problems with KURZWEIL PC2x

    Hi everyone,

    I have a KURZWEIL PC2x 88 key electronic piano and I have problems starting him up. Stayed for a long time with no battery and I have a feeling that lost all the software. I think I have to reload the BOOTLOADER and OS. Unfortunatly I do not get too far as no screen comes up. On power on flashes all the buttons (I think is reset) and than I get on the screen only solid squares, no matter how I adjust the contrast. Anyone had any experience with those and knows the correct steps for loading the software when you have nothing? I do have a computer running WINDOWS XP and a midi interface.
    Thank you fo ryour help.
    Regards,
    EUGEN IOV

  2. #2
    Supporting Member Jazz P Bass's Avatar
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    Have you attempted a hard reset?
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    huh, I have a Service Manual for PC2x. I atempted but hard to guess where you are on the menus when there is no message on the screen. Will try again. Thank you for the suggestion.

    EUGEN

  4. #4
    Supporting Member Jazz P Bass's Avatar
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    Can you upload the service manual here?
    The squares tells me that the LCD is not communicating.
    Do you have the backlight?

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    Here is the manual. If I turn the contrast pot one row disapear. Hard to tell if backlight working.

    Eugen
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  6. #6
    Senior Member Enzo's Avatar
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    Backlighting is simply illumination shining through the display. Turn out the lights in the room, if the display looks illuminated, it is backlit. If you see images on the display, then contrast is adequate.

    If your blank squares come up on the display, do they change or move around when you try to change patches?
    Education is what you're left with after you have forgotten what you have learned.

  7. #7
    Supporting Member Jazz P Bass's Avatar
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    Here is a zoom of the LCD circuit.
    The manual suggests reseating the connector.
    Check the power connections
    Pin 1: Vss (ground)
    Pin 2: Vdd (voltage)
    I still think the LCD is not being initialized.
    Possible causes:
    -Bad connection
    -Faulty LCD
    -Faulty U8 (bidirectional buss driver)
    -Faulty U6 (AND Gate)
    -Faulty main microprocessor.
    Here is a link that briefly describes the initialization sequence for an LCD.
    Link: LCD Initialization
    Attached Files Attached Files

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    Thank you Jazz. That gives me few clues. I'll let you know how I went

    Regards from down under,

    EUGEN

  9. #9
    Old Timer oc disorder's Avatar
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    Hi Eugen
    My sympathy's to you... its a heavy beast to work on it seems to take longer to dismantle and reassemble
    than fix.
    I had one a while ago and getting to the point the lonesome smd transistor Q18 was the culprit a MMBT2222.
    If you short pin 3 to ground (VEE) that should tell you as it will provide full contrast.
    I am assuming a lot here.
    Firstly on boot up all the red led's flash and after settling down the keyboard works but with no LCD.
    Obviously the test procedures are useless with no LCD.
    I think I was able to get an equivalent smd 2222 from Jaycar as they now stock some smd components.
    Not huge sellers however so you may have to shop around.
    Attaching a couple of jpg's for everyones elicitation to save trawling through the pdf.

    Did you notice Enzo's question
    "If your blank squares come up on the display, do they change or move around when you try to change patches?"

    The more info the better.
    Attached Thumbnails Attached Thumbnails kurtzweil-lcd.jpg   kurzweil-lcd-cont.jpg  

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    Hi you all,

    Thank you for your replies. I would like to mention that I bougth this piano in an auction. The piano was dessasembled and someone try to fix it. I never saw it working and I am not sure what is good and what is bad. End caps, supporting walls and power supply missing.
    I managed to purchase a power supply and end caps from the local dealer. Main board had no battery so I put a brand new battery in. Now when I put power I only see the reset (all buttons lit) and than on the screen apears these solid squares, there is no sound out and no buttons selected (red lit). No buttons lit when pressed. I guess the BOOTLOADER and OS is lost. I will follow all the suggestions and try to diagnose what is bad. I start with the assumption that everything is bad. If I manage to revive it I have a KURZWEIL PC2x, otherwise a pile of parts..... Also has a chip on the main board which I assume is the orchestral ROM option. I will post the picture of the chip. Would be that simple software lost or I still have hardware issues? Together with this piano I purchased 3 different KORG, fixed them all and working good (2 x M1 and 1 x 01/Wfd) and 2 different ENSONIQ which I have not look yet at them.
    Thank you again.
    EUGEN

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    Hi you all,

    I had a couple of days when I could not login. I guess was some site issues. Here is a picture of my ROM module. Anybody can confirm what this is? I think that this is the ORCHESTRAL option but I am not sure. On the sticker is written SK 582. Means anything?
    I did not progress much with my screen problems but I purchased a replacement screen ($95.00)from USA which is on the way. I checked voltages around and they all feel OK. I will spend more time with it in the weekend.
    Regards from down under,
    EUGEN
    Attached Thumbnails Attached Thumbnails sk582.jpg  

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    So, noone knows about this memory RAM chip????

  13. #13
    Noodle of Reality Steve Conner's Avatar
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    Nope, but I do know something about the LCD.

    The schematic pinout suggests that it is a standard HD44780 compatible LCD. Every one of these I've ever seen, displays one or two rows of blocks ("solid squares"?) when it is powered up but not initialised.

    And I've seen a few, not to mention written drivers for them.

    So, I'd suspect the processor over the screen in this case. I'm also surprised that you couldn't find a generic replacement for less than $95.
    "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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    Senior Member Enzo's Avatar
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    Your memory card says flash simm on it, the chip I can see says ROM on it, so I tend to think, at least for a start, that it is some sort of sample memory. I don't have this manual handy, but in additionb to the LCD initialization posted above, doesn't the keyboard as a whole have a reinitialization procedure? I get concerned when we start throwing tons of parts at something. Most things need just a little help. Even things that appear totally screwed up, often just need memory reset to factory defaults.
    Education is what you're left with after you have forgotten what you have learned.

  15. #15
    Noodle of Reality Steve Conner's Avatar
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    I think the PCB is a generic board that can hold either ROM or RAM chips. However the chips are marked Kurzweil, a dead giveaway that they are sample ROMs.
    "Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"

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    Thank to all members for replies. Enzo, I tried to reset the keyboard but it is very hard to travel through menus as manual advise, with no display. Hard to select any options. Also, after starts up and flash of all keys there are no keys lit and no sound generated on output so I assume that keyboard is not functioning. I checked all voltages and they are present.
    Today with the help form instrumentalparts.com my new display arrived. I can not wait to get home and give it another try. If this does not work I have to start thinking anout a new main processor board. Wonder how I am going to locate one of those??? I will keep you posted just if someone is interested in a KURZWEIL PC2x.
    Regards from down under,
    EUGEN
    Attached Thumbnails Attached Thumbnails display.jpg  

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    Huh there was a big disapointment today. I tested my new arrived screen and I still have the same fault, SOLID SQUARES on the screen both rows. I understand that the screen does not initialize but I have no technoligy to work on surface mounted components. So now my only chance to progress is to try to find a MAIN BOARD or what KURZWEIL calls the engine board, P/N: N01230051. Does anyone has one of these board even used or have any ideea where I can get one functional?
    Thank you for your help again,
    EUGEN

  18. #18
    Supporting Member Jazz P Bass's Avatar
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    Back to Post #7.
    Have you verified that U6 & U8 are good?
    You need a scope to monitor the initialization process.
    Ultimately it comes from the main microprocessor.

  19. #19
    Senior Member Mars Amp Repair's Avatar
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    Well,
    As mentioned above the power supplies is the best place to start on something as complex as this is. There is the regulator for 3volts which is crucial...they call one of them VR2 on page 107. also are you able to verify that the 2 crystals Y-1 & Y-2 are oscillating? Is there any data on the data lines anywhere?

    on page 114, there is what looks like a header plug J301 that has many of the power supply pins on it as well as a pin called 'PowerUpReset'. I'm not sure where that reset originates, but a reset line stuck in 'reset' mode can cause the keyboard to do nothing as you are describing...there are so many reset lines in there it may be difficult to determine where they originate from.

    It gets tough when trying to figure out if the unit actually has a 'hard component' issue, or as you've mentioned if it just lost it's program & won't boot because of that.

    glen

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    Does the sound generation circuitry work when you play keys, and it's just the display that is down?

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    Quote Originally Posted by bkahuna View Post
    Does the sound generation circuitry work when you play keys, and it's just the display that is down?
    No, nothoing works and no sound.
    In order to diagnose I made a little lab with Connector Board + CPU board and display. I think it should start with these 3 boards without the front panel and keyboard assembly. I have to get out my osciloscope and do some diagnostics. This has an external power supply with 2 voltages. I installed a brand new battery when I started and notticed the other day that went down to 2.9v so there is somewhere a short. I will follow all the suggestions.
    I contacted musicparts.com which still sell those boards. They want $745.60 for the engine board and $350.00 for the conector board.
    If there is anyone out there which has an used Engine Board for PC2x or connector board please let me know. Happy to buy another one. I would love to get this piano working as it has an inclredible keyboard assembly(heavy).
    Thank a lot to all contributors.
    Best regards from down under,
    EUGEN

  22. #22
    Old Timer oc disorder's Avatar
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    Eugene there's one working with orchestra rom for sale on Gum Tree in Aust for $1,400.00 Negotiable !
    If I were you I wouldn't pump any more money into the one you have as you could spend that amount on old boards and it still may not work.
    Kurzweil PC2X 88 note controller workstation with Orchestra ROM | Keyboards & Pianos | Gumtree Australia Marion Area - Sheidow Park

    Looks like it has been looked after too judging by the condition of the manuals.

  23. #23
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    Quote Originally Posted by oc disorder View Post
    Eugene there's one working with orchestra rom for sale on Gum Tree in Aust for $1,400.00 Negotiable !
    If I were you I wouldn't pump any more money into the one you have as you could spend that amount on old boards and it still may not work.
    Kurzweil PC2X 88 note controller workstation with Orchestra ROM | Keyboards & Pianos | Gumtree Australia Marion Area - Sheidow Park

    Looks like it has been looked after too judging by the condition of the manuals.
    I would pay on old boards $200-300 or around that not more. I will not spend $1,400.00 plus freight when I already have one! Even if you negotiate you have to spend over $1,000.00, plus where is the satisfaction to repair something?

    Thank you for your thoughts!!!!

    EUGEN
    EUGEN

  24. #24
    Senior Member Mars Amp Repair's Avatar
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    yeah,
    you also have to be careful as some of the key contact strips could also be bad. I'm not certain about the PC2, but many of those key contact strips are no longer available as well as quite often the key weights start breaking. glen

  25. #25
    Senior Member Mars Amp Repair's Avatar
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    this may seem simplistic & you may have already done this...have you just disconnected the display to determine if it is loading down some of the data lines? I experienced this once on an Alesis board...glen

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    Thanks OC disorder: Q18 turned out to be the issue in the PC2x I was working on too, and your post saved me some time! The LCD remained blank at all times...the contrast pin was high 5.7 volts no matter where the contrast pot was turned, and the issue was able to be traced back to q18. By the way that transistor is used in a really simple circuit, I think most NPN silicone general purpose transistors could substitute for that.
    Thanks!

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    Eugen, I'm hoping you can help me out, my church has pc2x keyboard that been acting up (screen locks up after startup) hoping you still have a copy of the service manual for the pc2
    that maybe YOU loan , send copy of to me so I can trouble shot this keyboard. And any ideas what might be causing this problem, or anyone else had this condition with the pc2

  28. #28
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    Hi there,

    Here is the manual. Good luck

    Regards,
    EUGEN
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    Last edited by eugen_syd; 06-18-2013 at 05:23 AM.

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    Hi Everyone,

    It has more than a year since I started this thread. Finally I got my PC2x working with help from Duane Gavin. I packed nicely my power board and engine board. I am glad I did that as he discovered that U1 was missing on the engine board. Took me more than 15min just to find it on the board and compared with previous picture and yes, was not there...Still after replacement did not come up immediatly, he reprogrammed the ROM chip. Now he also loaded v4.0 of the operating system. THANK YOU AGAIN DUANE, some people call him INSAINE DUANE I call him, INCREDIBLE DUANE.
    Only took like 4 days turn around plus the time to travel to Australia. I will donate this keyboard to my small church and I make sure people mention Duane in their prays.
    All the best from down under,
    EUGEN
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  30. #30
    g1
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    Glad to hear you had good results, in case anyone needs, here is a link to Duane's Kurzweil repair:
    Kurzweil Digital Piano Repair
    Quote Originally Posted by Justin Thomas View Post
    In my ideal world, I'm not too loud - your room is too small!

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    I as well had to replace Q18, the MMBT2222ALT contrast bias transistor on the connector board. The transistor was apparently damaged by a brief imbalance between the +12v and -12v supplies which fed the contrast pot/transistor circuit. The PC2X owner tried to force a broken 4 pin power supply connector into its receptacle. Shame on the engineer who spec'd such a flimsy DIN connector on an otherwise remarkably tough keyboard (excluding the Fatar lead keyweights!).

    Thanks for the tip on Q18!!!

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    I'm experiencing this same problem with a PC2x. When I switch it on, all the LEDs on the buttons flash and the display is blank just showing blocks. When I opened it up there was poor job replacing C3 on the engine board which I fixed. And the battery is reading just fine. It sounds like I need to get the OS updated and a reprogrammed ROM chip?

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