Problems with KURZWEIL PC2x

[eugen_syd]

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

[Jazz P Bass]

Have you attempted a hard reset?

[eugen_syd]

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

[Jazz P Bass]

Can you upload the service manual here?
The squares tells me that the LCD is not communicating.
Do you have the backlight?

[eugen_syd]

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

Eugen

[Enzo]

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?

[Jazz P Bass]

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

[eugen_syd]

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

Regards from down under,

EUGEN

[oc disorder]

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.

[eugen_syd]

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

[eugen_syd]

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

[eugen_syd]

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

[Steve Conner]

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]

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.

[Steve Conner]

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.