rabbitgeeks Posted May 29 Share Posted May 29 I bought my PC3k8 back 2013. For some reason, I stopped using it from 2016 until today. Today I powered it, turned it on, I got what described on title. As my living city has no Kurzweil service facility, I tried to fix it myself. After remove the case, I found out this yellow chip under the display circuit board, which seems has some legs broke off. However, I can't be sure if this is the problem, because I never powered my PC3k8 since 2016 and that chip doesn't look like burnt. I also made sure all the ribbons and connectors are properly connected, still nothing works. Any idea will be sincerely appreciated.😀 Sorry for my cumbersome English. Quote Link to comment Share on other sites More sharing options...
Jose EB5AGV Posted May 29 Share Posted May 29 That part is the high voltage transformer for the display backlight. And that is working... I would look for any battery, which may be depleted and preventing the unit to power up correctly. If that is not the case, you need to check power supply voltages and such. And look for any suspicious leaking or bulged capacitor. All in all, the display is not the problem, as even without display, you should have sound and buttons would be operating. So the problem is on the control side of the keyboard. 1 Quote Link to comment Share on other sites More sharing options...
Delaware Dave Posted May 29 Share Posted May 29 Forget what was said about the battery in the above post, the only thing the battery does on the PC3 series is power the clock and provides for an accurate time stamp on file saving, other than that it serves no other purpose. It will need servicing; shipping is expensive so you might be out of luck ..... Quote 57 Hammond B3; 69 Hammond L100P; 68 Leslie 122; Kurzweil Forte7 & PC3; M-Audio Code 61; Voce V5+; Neo Vent; EV ELX112P; GSI Gemini & Burn Delaware Dave Exit93band Link to comment Share on other sites More sharing options...
ProfD Posted May 29 Share Posted May 29 If it is worthwhile to get the PC3K8 fixed, consider paying (flight, lodging and service fee) a technician to come there.😎 Quote PD "The greatest thing you'll ever learn, is just to love and be loved in return."--E. Ahbez "Nature Boy" Link to comment Share on other sites More sharing options...
Jose EB5AGV Posted May 29 Share Posted May 29 8 hours ago, Delaware Dave said: Forget what was said about the battery in the above post, the only thing the battery does on the PC3 series is power the clock and provides for an accurate time stamp on file saving, other than that it serves no other purpose. It will need servicing; shipping is expensive so you might be out of luck ..... Sorry, I was not specifically talking of the PC3, but in general, as sometimes a bad battery can cause serious issues and not power up correctly on other gear. I stand corrected 🙏🏻 Quote Link to comment Share on other sites More sharing options...
J.F.N. Posted May 29 Share Posted May 29 Wouldn't a service manual and an experienced music electronics service tech be a able to deal with this? It's not exactly rocket science! Quote "You live every day. You only die once." Where is Major Tom? - - - - - Band Rig: PC3, HX3 w. B4D, 61SLMkII Other stuff: Prologue 16, KingKORG, Opsix, MPC Key 37, DM12D, Argon8m, EX5R, Toraiz AS-1, IK Uno, Toraiz SP-16, Erica LXR-02, QY-700, SQ64, Beatstep Pro Link to comment Share on other sites More sharing options...
Delaware Dave Posted May 29 Share Posted May 29 39 minutes ago, J.F.N. said: Wouldn't a service manual and an experienced music electronics service tech be a able to deal with this? It's not exactly rocket science! If I'm not mistaken I have a service manual for the pc3 series .... 1 Quote 57 Hammond B3; 69 Hammond L100P; 68 Leslie 122; Kurzweil Forte7 & PC3; M-Audio Code 61; Voce V5+; Neo Vent; EV ELX112P; GSI Gemini & Burn Delaware Dave Exit93band Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 11 hours ago, Jose EB5AGV said: That part is the high voltage transformer for the display backlight. And that is working... I would look for any battery, which may be depleted and preventing the unit to power up correctly. If that is not the case, you need to check power supply voltages and such. And look for any suspicious leaking or bulged capacitor. All in all, the display is not the problem, as even without display, you should have sound and buttons would be operating. So the problem is on the control side of the keyboard. I checked the battery as you pointed out, it indeed depleted. I exchanged it with a new one, but nothing changed. Next step I would try the power supply units. Thanks Jose😄 Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 10 hours ago, Delaware Dave said: Forget what was said about the battery in the above post, the only thing the battery does on the PC3 series is power the clock and provides for an accurate time stamp on file saving, other than that it serves no other purpose. It will need servicing; shipping is expensive so you might be out of luck ..... There is no company officially dealing Kurzweil right now in my country... I checked local forums, like everybody complains there is no way to fix Kurzweil and it's broke so frequently😬 Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 4 hours ago, ProfD said: If it is worthwhile to get the PC3K8 fixed, consider paying (flight, lodging and service fee) a technician to come there.😎 Yeah, I think my only chance is to fix it myself with help, if failed, seek for a lock general electronics-technician. Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 1 hour ago, J.F.N. said: Wouldn't a service manual and an experienced music electronics service tech be a able to deal with this? It's not exactly rocket science! You are right JFN, I just wanna to know what happened inside and to try to fix it myself first. 1 hour ago, J.F.N. said: Wouldn't a service manual and an experienced music electronics service tech be a able to deal with this? It's not exactly rocket science! Love you profile photo by the way😺 1 Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 1 hour ago, Delaware Dave said: If I'm not mistaken I have a service manual for the pc3 series .... It's downloadable at their website 1 Quote Link to comment Share on other sites More sharing options...
ProfD Posted May 30 Share Posted May 30 12 minutes ago, rabbitgeeks said: Yeah, I think my only chance is to fix it myself with help, if failed, seek for a lock general electronics-technician. Right. If you're willing to try repairing it yourself, enlisting a local electronics tech would still be cheaper than my suggestion which was based on no service center nearby. The instrument is over a decade old so it's clearly outside every warranty window.😁 Good luck getting the PC3K8 back up and running. Once it's fixed, turn it on more often than years.🤣😎 Quote PD "The greatest thing you'll ever learn, is just to love and be loved in return."--E. Ahbez "Nature Boy" Link to comment Share on other sites More sharing options...
rabbitgeeks Posted May 30 Author Share Posted May 30 9 minutes ago, ProfD said: Right. If you're willing to try repairing it yourself, enlisting a local electronics tech would still be cheaper than my suggestion which was based on no service center nearby. The instrument is over a decade old so it's clearly outside every warranty window.😁 Good luck getting the PC3K8 back up and running. Once it's fixed, turn it on more often than years.🤣😎 From my previous experiences, most of times, problem like this is nothing more than a loosen connector/dirty pin or something alike. So I wanna open it to see myself first.😁 Thanks ProfD, I'll definitely play the hell out of it! Quote Link to comment Share on other sites More sharing options...
Jose EB5AGV Posted May 30 Share Posted May 30 Look for capacitor damage / leakage. I have fixed lots of electronics over the years and electrolytic caps are one of the first suspects, specially if the gear was working and, after some time unused, doesn't. BTW, where are you located? PS: there is a repair sub-forum, perhaps this thread could be there Quote Link to comment Share on other sites More sharing options...
J.F.N. Posted May 30 Share Posted May 30 13 hours ago, rabbitgeeks said: You are right JFN, I just wanna to know what happened inside and to try to fix it myself first. Love you profile photo by the way😺 Apparently it's a legend (the profile photo origin..). Quote "You live every day. You only die once." Where is Major Tom? - - - - - Band Rig: PC3, HX3 w. B4D, 61SLMkII Other stuff: Prologue 16, KingKORG, Opsix, MPC Key 37, DM12D, Argon8m, EX5R, Toraiz AS-1, IK Uno, Toraiz SP-16, Erica LXR-02, QY-700, SQ64, Beatstep Pro Link to comment Share on other sites More sharing options...
YashN Posted May 30 Share Posted May 30 An alternative is to replace the display itself by a LED lit one. It's a different type that doesn't require the high-voltage power: Quote Kurzweil K2500XS + KDFX, Roland: JX-3P, JX-8P, Korg: Polysix, DW-8000, Alesis Micron, DIY Analogue Modular Link to comment Share on other sites More sharing options...
Jim Alfredson Posted June 5 Share Posted June 5 As @Jose EB5AGV pointed out, it isn't the display as the display is working. Always start with the power supply rails. Make sure the correct voltages are being output with little ripple. Most likely the issue is bad filter capacitors on the rails either at the power supply itself or on the boards. Quote Keep it greazy! B3tles - Soul Jazz THEO - Prog Rock Link to comment Share on other sites More sharing options...
rabbitgeeks Posted June 6 Author Share Posted June 6 On 5/30/2024 at 11:04 PM, J.F.N. said: Apparently it's a legend (the profile photo origin..). Hahaha damn keyboard cat so damn cute😹 1 Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted June 6 Author Share Posted June 6 On 5/31/2024 at 3:15 AM, YashN said: An alternative is to replace the display itself by a LED lit one. It's a different type that doesn't require the high-voltage power: Thanks your reply YashN. I saw this video, but I don't have a spare display for replacing, and currently I think the problem is most likely on the power supply. I think I will try the display replacing as the last resort, thanks. Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted June 6 Author Share Posted June 6 On 5/30/2024 at 1:23 PM, Jose EB5AGV said: Look for capacitor damage / leakage. I have fixed lots of electronics over the years and electrolytic caps are one of the first suspects, specially if the gear was working and, after some time unused, doesn't. BTW, where are you located? PS: there is a repair sub-forum, perhaps this thread could be there Thank you Jose, I can't eye-pick any burnt or swell capacitor, I think It's time to get my multimeter some flexing. I live in a small city located in heartland of China. In China, Kurzweil products are distributed by a subsidiary of Kurzweil's parent company Young Chang. This company's official site is still online, but phone and email are already dead now. Damn Xi Jinping is driving every foreign companies away. Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted June 6 Author Share Posted June 6 17 hours ago, Jim Alfredson said: As @Jose EB5AGV pointed out, it isn't the display as the display is working. Always start with the power supply rails. Make sure the correct voltages are being output with little ripple. Most likely the issue is bad filter capacitors on the rails either at the power supply itself or on the boards. Thank you Jim, I'm gonna do as you say☺️ Quote Link to comment Share on other sites More sharing options...
rabbitgeeks Posted June 8 Author Share Posted June 8 Today I hired an electrician to check out my keyboard. He exempts the power supply as the problem, power rail seems well enough(guy even checked if my house power supply is properly grounded). Every voltage reading he got seems to approximate idea values marked on the service manual. At last, he got his suspicion on this EPROM. The service manual says "The PC3x uses a 32 pin EPROM located at U4 to store the boot up information for the CPU." He removed this EPROM and power up to see what will happen. Nothing happened, the symptoms seem identical to the state with EPROM attached. The problem is that I have no way to get a spare EPROM for replacing, so we can't certain if this EPROM is the cause. 😓 Quote Link to comment Share on other sites More sharing options...
YashN Posted Thursday at 03:52 PM Share Posted Thursday at 03:52 PM I'd try another display rather than another EPROM first after checking the PSU rails. Quote Kurzweil K2500XS + KDFX, Roland: JX-3P, JX-8P, Korg: Polysix, DW-8000, Alesis Micron, DIY Analogue Modular Link to comment Share on other sites More sharing options...
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