Yamaha RM1x LCD replacement

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Yamaha RM1x LCD replacement

Unread post by alinchican » Sun Jan 08, 2017 5:10 pm


This is my first post here. 0-)

I've bought a RM1x some days ago and discovered a non-working LCD display. I've discovered a few thread/guides on this forum with users replacing their SY77/99 display with a generic one. This discovery gave me hope that we can accomplish the same thing on the RM1x without spending 100-150$ on an original part that seems flimsy and is hard to replace in the future.

Noob here, I'm going to help by listing some helpful resources, maybe (I hope) others more experienced can help.

We are looking to replace LCD Assembly (part number V2737900).

RM1x info

RM1x Service Manual - pages 13-14 info for lcd controller, page 53 for circuit diagram, section G3
SED1335F0B LCD Controller datasheet
Contrast potentiometer (B 1.0K RK09K111, taken from documentation)

Relevant block and circuit diagrams attached.

CN6 cable pinout for LCD unit between LCD controller and contrast potentiometer
Pin 1 - Contrast pot - ?
Pin 2 - Contrast pot - ? Ground?
Pin 3 - XD3 - 4-bit X-driver (column drive) data output
Pin 4 - XD2 - 4-bit X-driver (column drive) data output
Pin 5 - XD1 - 4-bit X-driver (column drive) data output
Pin 6 - XD0 - 4-bit X-driver (column drive) data output
Pin 7 - LP - X driver Latch pulse - LP latches the signal in the X-driver shift registers into the output data latches. Connect LP to the Y-driver shift clock on modules.
Pin 8 - YD - Scan start pulse/signal- YD is the data pulse output for the Y drivers.
Pin 9 - Ground?
Pin 10 - WF - Frame signal for X/Y driver - LCD panel AC drive output. The WF period is selected to be one of two values with SYSTEM SET command.
Pin 11 - XSCL - X-driver data shift clock - The falling edge of XSCL latches the data on XD0 to XD3 into the input shift registers of the X-drivers.
Pin 12 - 5V?

CN9 cable for backlight provides 5V.

LCD Proposals

We are looking for LCDs that support 4 bit connections and are similar in size.
LM24064B - seems okish in size, smaller viewing area, pinout seems ok

Do you think the LCD is ok? Any help would be appreciated. Thank you!

L.E.: I think we need an LCD compatible with the SED1335F0B controller. Bummer.
L.L.E.: The newer RA8835 is compatible with SED1335F0B... sooo.. we must find an LCD compatible with RA8835 but without the controller. Removed old LCD proposal.
L.L.L.E: Added another display which seems too wide, needs to be checked.

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Re: Yamaha RM1x LCD replacement

Unread post by alinchican » Tue Jan 10, 2017 7:17 pm

I think I've managed to review all the commercially available 240x64 LCDs on the market. :)

After opening the R1Mx and making some measurements, I'll proceed with buying the LM24064B display from TOPWAY.

Wish me luck!

L.E.: 16.01.2016 - I haven't managed to buy the LCD, the only supplier in Europe couldn't sell me just 1 piece. Minimum order is 100$. :( I have contacted the manufacturer directly and now I'm waiting for a response.
L.L.E: 24.01.2016 - Still no reply from the manufacturer. I think we are out of luck.
Last edited by alinchican on Tue Jan 24, 2017 2:07 pm, edited 2 times in total.

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Re: Yamaha RM1x LCD replacement

Unread post by Miks » Tue Jan 10, 2017 9:11 pm

Yes mate - we DO wish you luck! 0-)

Please keep us informed how you go on - could be of help for others being in need of a display replacement. 8)

My (key related) gear (in alphabetical order):
Kawai: K1 II
Korg: M1 (up'd to EX, w/ 'Cool Blue'), M1REX (w/ 'Cool Blue'), Poly-800
Roland: D-50, D-110, D-550, PG-1000
Yamaha: AW1600, DX7IID (w/ 'Cool Blue'), EX5R, RM50, RX5, SY99 (w/ 'Cool Blue'), TG500, TX-802, YMM2
Sector101: SYEMB05 (5x), SYEMB06 (3x), EXFLM2 (1kit), MCD Sweet16 (1x), WaveBlade 8MB Card (1x) & 1x Programmer Unit for WaveBlade

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Re: Yamaha RM1x LCD replacement

Unread post by alinchican » Mon Feb 13, 2017 2:34 pm

Hello guys!

Unfortunately I hit a dead end. I couldn't contact the LCD supplier and I couldn't afford a 100E minimum order on another website which only sells to companies.

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Joined: Mon Jul 03, 2017 5:48 pm

Re: Yamaha RM1x LCD replacement

Unread post by Humpink » Sun Jul 16, 2017 4:01 pm

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Re: Yamaha RM1x LCD replacement

Unread post by alinchican » Mon Jul 17, 2017 2:26 pm

Hello Humpink,

Thanks for the reply. That display was also on my list but I think I discarded it due to its large size. It should theoretically work.

I have managed to replace the old display with LM24064B but I can't fully test it. Something else is broken. :roll:

I'm seeing all the pixels active with no other screen update. I had the same problem before replacing the display. I also replaced the LCD driver (SED1335F0B) chip with no change.

I'll be rewriting the OS chip next. Have any of you encountered this?

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