Roland XP50 LCD Display Problems

Forum for JD, JV, XP and XV synthesizers from 1990's
mp3ireland2
Posts: 30
Joined: 16:47, 11 January 2016

Re: Roland XP50 LCD Display Problems

Post by mp3ireland2 »

THanks for the link and the info!
Horizonsound
Posts: 5
Joined: 00:40, 28 January 2016

Re: Roland XP50 LCD Display Problems

Post by Horizonsound »

Hi All,

I recently picked up an XP50 through ebay (not working). This one obviously had a hard life.
Battery replacement and factory reset got it to operate initially.
The disk drive was seized, but managed to free up the drive motor and now it works. Note, these are SHUGART drives, so a replacement was rather difficult.
The expansion board only recognised EXP-A position, but after cleaning up the connectors on the other three, managed to get those running as well.
The encoder was erratic. I've got a new one on order from Syntaur, as I could not find a direct replacement for the part no. through element14 or mouser. They are obsolete.
Many buttons are starting to fail. Replacement on their way.

The big issue now is that the keyboard is freezing after being turned on for 10secs. Display goes dim (characters are slightly visible), but nothing responds, and no sounds. Voltages seems to be all good when it goes into this state.

I'm going to replace all the caps when they arrive.

FYI, i've fixed up a number of JV synths recently, including a JV80 with the dreaded red-goo (easy fix with NaOH) and many broken PCB traces, and a JV35 that had beer and tobacco all through it!

If anyone has experienced the freeze issue before, please let me know. I'm suspect of C65 with is in the reset circuit(?)

Anthony.
Horizonsound
Posts: 5
Joined: 00:40, 28 January 2016

Re: Roland XP50 LCD Display Problems

Post by Horizonsound »

I replaced C65 for the time being with a 10uF (in lieu of 4.7uF) and it seems to be running fine now...
Jazzbassist220
Posts: 3
Joined: 19:39, 21 November 2016

Re: Roland XP50 LCD Display Problems

Post by Jazzbassist220 »

Hello, I wonder if there's still anybody out there from this 6 year old post; I just found this while looking for a solution to my problem: synth turns on, orange display lit but no characters and no sound at all; battery has been replaced a few months ago and all was fine until recently; if I let it stay on for a few minutes it would come to life and work fine until turned off again, but now it won't work at all. Has anybody found if the problem was the power transformer, by any chance? Thanks!
dgtl311
Posts: 1
Joined: 23:52, 11 February 2017

Re: Roland XP50 LCD Display Problems

Post by dgtl311 »

Hi Cesarsound,

I was hoping with all of your expertise on the Roland XP-50 that you could provide some advice:

I purchased a dead XP50 in hopes of bringing it back to life. It has the infamous blank display and I have replaced all of the caps on the main board. I noticed some leaky caps, but no damage to any of the traces or surrounding components that I could see under magnification. Replacing all of the main board caps didn't change anything. Voltages seem to check out as per the service manual, but I only checked the power supply and various points on the main and exp board. I should also note that it has a brand new CR2032 and the stop/play button or heartbeat is a solid red and does not blink. Pressing any buttons has no effect and there is no sound on any of the outputs when pressing the keys.

I really appreciate any advise you can offer.

Many Thanks,

dgtl311

UPDATE: I ended up finding 2 broken traces from IC12, which I repaired. It now has a heartbeat and I have audio output, although it it sounds like every patch has some extreme vibrato on it. Still nothing on the display, but at least I've made some progress. Is there a way to do a hard reset without using the display?
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CesarsoundOne
Posts: 203
Joined: 21:29, 9 October 2014

Re: Roland XP50 LCD Display Problems

Post by CesarsoundOne »

A solution for no text on display (only orange light):
My XP50 had the same problem of yours: display backlight is lit (orange) but no characters appear on it. This is a problem on contrast adjust circuit.
-just remove the wire that is on pin # 3 of CN14 and solder this wire to the ground of PCB mainboard.

Some tips for the sound problems:
3-Replace all electrolytic capacitors, especially the C931, C932 and the caps that are on analog signal path like C6, C7, C8, C11, C174, C175, C86, C90.

4-Test all the muting circuits that that composed by:
A: Q13, Q14, C902 and IC37 are the muting circuit of DA converter - you should read a voltage of aprox. 12-15vcc on pins 7 and 8 of IC19 (the 18bit DA converter).

B: IC1A, Q11, Q1, Q2, Q8, Q9 form the output muting circuit. You should read a voltage of aprox. 0 to minus (-)5vcc on junction of R148 and R132 to have sound on output (muting off).

5-Test the direct output of DA converter: Check if there is sound on pin 11 and 6 of IC19 (the 18bit DA converter). You should use an oscilloscope or an audio amplifier here.

6-Do a visual inspection on all PCB wirings of motherboard using a magnifying glass, to see if there is some trace of leaked electrolyte from capacitors, because the electrolyte can destroy the PCB wirings. If you find a damaged wiring, you should try to reconstruct it.
Subtox
Posts: 4
Joined: 17:55, 8 March 2016

Re: Roland XP50 LCD Display Problems

Post by Subtox »

I too am having sound issues with my XP-50. I turned it on for the first time in years and got a hissing sound and a tiny bit of distorted audio when I pressed keys. At the advice of multiple forum threads I replaced all of the electrolytic capacitors on the mainboard. However now, there is no sound at all! Utter silence.

I should say I'm not an electronics expert and had a tough time with the job (although looking at my work I clearly got better as I went, haha). Here are the details of what I fixed, the mess I made, and the troubleshooting I've done. Any help as far as a next step would be appreciated.

For a few reasons, I replaced the SMD's with through-hole capacitors, by bending feet and soldering them to the pads. I was careful to buy the correct uF and voltage components. A couple of the originals were 6v and the supplier only had 6.3v, which I understand is OK.

Due to my lack of experience, and not helped by the old adhesive, I managed to lift a few pads from the board and break a few traces. I fixed these by either gluing the pads back down where still intact, or using wire strands to connect the capacitors back to the circuit further down the trace. I read the schematic carefully to make sure I was not bypassing any important components, and I did continuity tests in those areas afterward to make sure there was a signal.

I found that C932 was soldered in backward (it is paired with C931 but facing the opposite way, so as an oversight I soldered them in the same direction). I didn't notice any issues with the capacitor (pops, burns, etc.) so I corrected it and then did some continuity tests.

I also tried testing the capacitors themselves but I wasn't about to remove each of them from the board to do so, which I believe is necessary for a true test. The unit was turned off and unplugged, and I simply attached my multimeter leads to each side of the capacitor to see if I was getting an Ohms reading. In most cases it would flash a number like 1000-1500 and quickly return to 1, which I understand is what you want. Some capacitors stayed at a higher number though and I'm not sure if I was doing something wrong or those capacitors are bad.

Following the advice of CesarsoundOne's most recent post, i tested the voltage on pins 7 and 8 of IC19 and got 0 volts. Again, I could very well be doing something wrong. I powered on the unit, connected the negative lead of my multimeter to ground (one of the mainboard mounts with the screw holes), and the positive to pin 8, and then pin 7. For both of these, the multimeter quickly went back and forth between 0 and .01 volts. (As a troubleshooting measure I tested the battery and got 3 volts so I'm sure I have a good ground.)

I went into test mode on the unit and went through all the tests. All of the non-sound-related tests passed, however there was no sound for any of the sound tests. Also the after touch test failed, which was supposed to register a keypress but didn't. Although when I press keys in Perform mode the LEDs in the center section just below the LCD blink, so there is a signal coming from the keyboard.

I have of course tried multiple cables, both the headphone and L/R outputs, different channels on my mixer, plugging different instruments and mics into those same mixer channels, playing songs from a floppy disk in case it was a keyboard problem (no sound comes from sequenced files either), and I recorded a few measures on the sequencer and looked in Microscope Edit to make sure notes were being registered (they are).

Phew, thank you if you are still reading. If anyone has any suggestions on what I can try next I would be very grateful! I can't bring myself to trash this thing just yet. Especially since it was making *some* sound before I tinkered around in there, I'm pretty sure it's just something I did wrong and not a fried IC or something major.

EDIT: More info including close-up photos can be found at a previous thread I posted at Electronics Point. https://www.electronicspoint.com/thread ... ry.282702/
Icebergbass
Posts: 6
Joined: 22:03, 14 June 2017

Re: Roland XP50 LCD Display Problems

Post by Icebergbass »

Hello, I know I'm a few years late on this thread, but I just came upon it, while searching for a solution on how to make my xp-50 work again. It's been working fine since 1997, when i bought it new. Suddenly, it wouldn't turn on, like there was no power; after leaving it on for a few minutes it started working again; now it takes a few minutes to start; the orange display stays on, bright, but no characters shown, no sound, no lit buttons; it will then work again, normally, like there's no problem at all, but will eventually stop working again and only the orange display with no characters comes up. Power supply, maybe? Thanks for any help!
Jazzbassist220
Posts: 3
Joined: 19:39, 21 November 2016

Re: Roland XP50 LCD Display Problems

Post by Jazzbassist220 »

CesarsoundOne wrote:A solution for no text on display (only orange light):
My XP50 had the same problem of yours: display backlight is lit (orange) but no characters appear on it. This is a problem on contrast adjust circuit.
-just remove the wire that is on pin # 3 of CN14 and solder this wire to the ground of PCB mainboard.

Some tips for the sound problems:
3-Replace all electrolytic capacitors, especially the C931, C932 and the caps that are on analog signal path like C6, C7, C8, C11, C174, C175, C86, C90.

4-Test all the muting circuits that that composed by:
A: Q13, Q14, C902 and IC37 are the muting circuit of DA converter - you should read a voltage of aprox. 12-15vcc on pins 7 and 8 of IC19 (the 18bit DA converter).

B: IC1A, Q11, Q1, Q2, Q8, Q9 form the output muting circuit. You should read a voltage of aprox. 0 to minus (-)5vcc on junction of R148 and R132 to have sound on output (muting off).

5-Test the direct output of DA converter: Check if there is sound on pin 11 and 6 of IC19 (the 18bit DA converter). You should use an oscilloscope or an audio amplifier here.

6-Do a visual inspection on all PCB wirings of motherboard using a magnifying glass, to see if there is some trace of leaked electrolyte from capacitors, because the electrolyte can destroy the PCB wirings. If you find a damaged wiring, you should try to reconstruct it.
Would these defective parts suddenly work fine again, like the problem never happened and then, the problem comes back? This is what's happening to my xp-50. It takes a while to boot after I leave in on, it works fine for some time and then the problem comes back: orange display lit but no characters, no sounds, no buttons light up.
Vindor
Posts: 2
Joined: 23:01, 10 January 2018

Re: Roland XP50 LCD Display Problems

Post by Vindor »

Hopefully there are still some readers of this thread...
I try to renovate my XP80 and use this very informative thread as an analogy to find out which capacitors of the XP80 need to be replaced to get a better sound.
I studied both the service notes of XP80 and XP50, and I try to find the equivalent capacitors of XP50's C931 and C932 in the XP80.
However, I cannot find those capacitors in the Service manual of the XP50. Maybe I overlooked them, but I studied the schemes in detail. I did find them on the lay-out picture of the Motherboard, but this gives no electrical information.
Can anyone point out where the C931 and C932 are located in the service manual of the XP50?

Kind regards,
Vincent
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CesarsoundOne
Posts: 203
Joined: 21:29, 9 October 2014

Re: Roland XP50 LCD Display Problems

Post by CesarsoundOne »

C931 and C932 do not appear in the service manual of the XP50, but are placed on PCB, as below picture.
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AncientGeek
Posts: 26
Joined: 17:24, 2 February 2018

Re: Roland XP50 LCD Display Problems

Post by AncientGeek »

Here's what I hope is useful information based on my restoration of an XP-50:

1. Don't assume that capacitors need replacing if the display is blank. If the backup battery is flat, the stored display contrast value will be lost and default to zero. In my case, replacing the battery and shorting the requisite line to ground temporarily ( as described in earlier posts) allowed me to see the display, do a system reset and adjust the display contrast.

2. Some have noted that the marked value on C63 and C83 is 0.1 uF, while others insist that they are 1 uF. I've measured the frequency of the PWM signal, and it's about 38 kHz. Therefore a value of 0.1 uF is entirely appropriate, and these two electrolytics could quite safely be replaced with ceramic capacitors of the same value. 0.1 uF is the same as 100nF, by the way.
cringey
Posts: 1
Joined: 13:56, 19 July 2018

Re: Roland XP50 LCD Display Problems

Post by cringey »

Hello everyone or anyone who is still reading here:

Typical XP-50 post. Just got one hoping it was just a battery change / factory reset fix.
Upon purchase: Orange screen no lights on buttons.

Try one: changed battery. Start Stop light flashes green. Attempted factory reset but no response. (turns out I missed a step which I discovered later on)

Try two: reseated all the connectors on main board. Still blank screen, however the buttons are all lighting up properly. Attempted factory reset but no response. (again turns out I missed a step which I discovered later on)

Try three: disconnected everything and gently cleaned all areas around the ic's and caps with 91% alcohol. The swabs were not too dirty afterwards. Put everything back together, performed the proper factory reset: I was doing DISK, 4, 5, Turning dial then enter, enter. Turns out I needed to hit enter before flicking the dial)

Still blank screen (tried the SYSTEM 2/10, INC but no response), buttons still lights up, but I am met with sounds! Distorted sounds, but still sounds (as someone described above.)

So it does look like a caps issue somewhere right? My next question is: should I buy the tools and parts to attempt this on my own? (I am a compulsive tinkerer, It took me 2 years to fix a blue screened Kurzweil K2500R but I did it) or how much do you think a repair place would charge? (Anyone know of any reasonable places in New Jersey?)

Thank you!

Update: I lost sound again last night and as I was looking closely I noticed that the cap C021 (the one between C922 and C902) was loosening and popped right off with a touch. There looked to be just a tiny bit of leakage underneath. I have a set of all the capacitors coming in soon so we will see where to go from there.

(Whenever I cleaned I must have pressed that cap back into position thus regaining the sound ?)
mackoscout30
Posts: 2
Joined: 05:46, 7 March 2021

Re: Roland XP50 LCD Display Problems

Post by mackoscout30 »

Hello,

Here I am trying to bring an XP50 from the brink.
Initially same situation as others - turns on, works for about 10 sec with no distortion then distortion comes in but menus continue to work.

After opening seen small leak at C902 - changed this only initially with no difference. So I went all out and did all the SMD caps.

After changing them was even worse (initially), figured out there was an open between negative leg of C175 and where it goes through the board (tiny trace).
Then also found R99 and R100 were opened (likely from leaking cap 902. Changed these and testing transistor Q13 seems like it has OK resistance to both base and emitter using diode mode on multimeter. There is 15v coming to collector (see photo attached) but no voltage goes to the emitter (which then would power the DAC ) - so there is no Voltage on pins 7 and 8 of IC19 (DAC).

I think this is the problem - I am not sure if I connected the “Base” correctly - as the Schematic has the traces obstructed by the thick dark “outlines”. If anyone can check on a working model or from past experience if the photo I am attaching is correct in my assumption of how things should be connected - or am I missing something?

Any help would be appreciated. If this is wired correctly then I think maybe Q13 transistor is the “problem” ?

Does anyone have a good idea of replacement for Q13? I see it is hard to find on the internet (would 2SC2873 be OK instead of 2SC2882?).

Can I just put in a diode between Q13 Collector and Emitter?

What does the “muting” circuit actually do?

Shouldn’t there be a resistor going to the Base? In that case my connection assumption is incorrect.

Thanks

Maciej
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mackoscout30
Posts: 2
Joined: 05:46, 7 March 2021

Re: Roland XP50 LCD Display Problems

Post by mackoscout30 »

Ok, got it fixed.
This circuit diagram helped a lot - thanks to a Friend and electronics guru.

Got some small wires hooked up - not pretty but functional.

This board has “tiny” traces. Wished I had a microscope.
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