I've had two JX-8P's, I had a pretty clean one I bought back in 2003, but it kinda sounded a bit cold, boring to me. I think I paid about $400 for it, and slightly more for the PG-800. I sold the JX for about $550 and the PG for I think $800 it so around 2005. But a year ago I found a totally mint one locally. One owner, classically trained pianist who hasn't used it for years. I took it out of the box, switched it on, everything worked! I used the iPG-800 app for a while to program it, but once I got used to editing on the machine, I found it almost as good. Funny thing, my old JX has the names of the patches on the keys (supposed to be older ones), whereas my new one doesn't (supposed to be newer) but mine was made in December '85, so go figure. This model also sounds much, much better to me, I didn't know if it's changed or if I've changed, but the new one sounds very warm and fat.
Being totally ignorant on electronics, I watched your video with sheer awe and fascination. It takes someone with incredible discipline and a deep sense of curiosity to master the complex (to me) world of electronics. I have a JX-8P that I’ve had since purchasing in the mid-80’s and which has sat in my basement (dry and fairly dustless, cool environment) since the late 90’s. I recently brought it up to fool around with and surprisingly, it still worked. The patches all work and sound fine although there is a noticeable, constant buzz. I plugged in the PG-800 to it and that worked too. There is an electronics synth repair place nearby (I’m in SoCal) but because they cater mostly to “rock stars” (as evident by the amount of signed 8x10 endorsement photos in the walls), their repair prices are steep and the wait is in months. That’s not to say that I don’t appreciate ir value the amount of tech troubleshooting/parts acquisition that’s involved. It’s just difficult to balance the justification. In any case, thanks for posting this! I may not have learned how to fix mine, but I have a better understanding of its components under the hood.
This is my new favorite channel. Ive seen all your videos and you have got me back to enjoying bench work/restoration and synths after a long sabbatical . Keep it up! Greetings from Sin City.
DCO is a Digitally Controlled (Analog) Oscillator. No one should classify this as a hybrid synth. Rather than using a voltage to set the frequency of the oscillator, it uses a timing pulse from a microcontroller or dedicated timing chip. After that, everything is analog wave shaping. There's also a whole lot of non-discrete circuitry on these synths. Maybe you meant through-hole? The JX-8P Sounds fantastic.
So glad I came accross this channel...I also have a 27mhz SSB cb radio addiction...both deal with oscillators filters etc. About to pull apart mt Roland Fantom XA apart to replace the 4 real time 10k pots but am having trouble finding replacement 10k pots at a reasonable price...
Wicked job as usual! Very cool of you to mock up that heatsink to help with the overheating problem. Very intuitive of you. Looking really forward to part 2 and all your future videos. These are my treadmill past time! =)
I know this is an old video, but thank you for saving this synth. Somehow I feel like we have to keep these old synths working for as long as we can. When they are gone, that's it.
I used to love my JX-8p for the killer pads! OMG it was so good at those but yes the display voltage control ran so hot it de-soldered it's self and burnt up the traces, I kept fixing and fixing it! I perfected a Han Solo style fist thump near to the display that would bring it back to life when it failed! :D Waiting for it to reboot 8...7....6....5.... was a heart stopper if you used it live!
@bradthx - I know it's been almost a couple of years since you posted this, but seriously - THANK YOU. Your series are super detailed, easy to understand, and just top notch tutorials. You've given me the courage to pull my own JX-8P apart and attempt some repairs (keybed is acting up, need to replace a broken key, aftertouch is shot). Thanks again!!!!!
Nice series you did on this synth. My JX-8P is exhibiting the aftertouch issue as well, and the data slider while not completely out isn't working exactly precisely either - may just be a case of it being dirty. I also have several keys where the notes won't come on or they get stuck on. Been using it as a tone module with another controller but I think maybe I'm going to have to open mine up and clean it up and fix it up - I also have a Juno-106 that has an issue on voice #5 so need to fix her as well. Ironically my JX-8P also has the faded off paint next to the volume slider and it was like that when I got it - maybe it belonged to the same family yours came from? LOL who knows. Otherwise mine is in fairly good shape cosmetically (I got mine back in 1993 sometime for around 500 bucks).
It actually has DCO not digital oscillators. A DCO is different from a digital oscillator in the fact that a digital one produces its sound from a digital sample of a waveform. A DCO is an analog oscillator that is controlled by digital circuitry. The digital half is only there to stabilize to tuning of the oscillator.
I also got an 8P cheap also because of similar issues - a friend helped me replace the bridge rectifier and it's mostly running ok the past years since. It still has not such great condition slider pot's, and missing headphone jack, too. Can you recommend what I would search for to find the aftermarket suitable fader pots? Can def recommend iPad iPG800 app for controlling the parameters!
Good video. Like you I'm an electronics engineer with a love of synthesizers since I was a kid so back to the mid 70's. I've also bought faulty a juno 106 which I need to repair and add a kiwi 106 upgrade to. Also bought a good JX8P which the aftertouch doesn't work on and also have a kiwi JX8P kit to add to that. Your video has let me know what to look forward to inside the unit and good advice on the PSU. Off to watch part two now.
The Kiwi patch editor looks quite good, yes they are expensive but can be used with quite a few synths, just thought I would mention it for people who do not know about it. I'm enjoying your videos, only just came across them, now I have another resource for repair info.
I’ve Just purchased one, here in September 2021. Fully functional with Roland soft bag, foot peddle and two tier stand, $225. Still can’t believe it. Couldn’t really afford it, but couldn’t afford to not buy it either. A once in a life time opportunity.
This is great, can't wait for part two! A funny note: I think I've got the "brother" of your JX-8P as they were auctioned together by the same eBay seller. Mine is in a slightly better shape, but with several dead keys. I'm learning a lot from your videos, please keep posting : )
Thank you for a great video :-) I just bought a JX-8P together with a PG-800. Unfortunately the PG-800 controller does not work no matter what I do, the synth seems to work all right. The previous owner said he haven't used the controller for 20 years. How big of a chance do you think it might just be the din cable that needs to be replaced? The synths and the controller looks in good shape.
nice video, noticed the graphics are slightly different than on my JX-8P. Super nerdy observation LOL. The patch number is in the centre of the button., on mine it's on the left
I’ve watched several demonstrations of the 8P on RUclips, not to mention one or two other refurbishment examples. It was worth clicking on this one only for that instance at 25:54 when you test the data slider and use it to control the filter cutoff. I don’t think I’ve seen anyone demonstrating the edit parameters of this synth on the front panel, just with the PG-800 or some other third-party controller.
Do you have the schematic for this and where did you find the full wave bridge rectifier for this thing? My 5 volt supply is out. I guess I'm building it for now. Nice video man!
I am glad you are pointing out that the bridge rectifier is running near it's thermal limits. I have MKS-70 (2X jx8p) and it does get very hot inside. Perhaps upping the rating on the rectifier? DCO is not really digital. It has IC counters that divide CPU clock to re-trigger the generation of saw wave core oscillator which is analog (capacitor discharging/charging cycle). It also sends signal to increase/decrease amplitude of the wave. Wave shaping (analog) happens after that
Yeah, that was poor wording by me. I was simply specifying that this synth has a DCO based oscillator source vs. analog VCO oscillators found in the Jupiter and early Juno synths. As for the rectifier, I did actually up it to a 6A unit mounted to the heatsink, will be in part 2 that I should get upload soon. Thanks for watching!
Hey brad I have done similar repairs to my JX8P but have two issues. One is sometimes hanging notes that occur occasionally and notes that don't sound that is not the same note. Seems possible it may be keyboard scanning may be overwhelmed or have fault. Any suggestions?? I did the after touch repair the hard way and seems to be still working ok but really like your solution and will implement your bridge rectifier cooling solution. looks cool .
Seems like a really common issue on the JX-8P. I had one 20 years ago with stick keys, hanging notes, so does the new one I just got. I suspect it may be something dirty or corroded inside that's causing it
@bradthx Thanks so much for making this! You helped me troubleshoot the power supply on my JX-10 when it suddenly quit powering up. Luckily everything checked out and it just seemed to be a loose connection. Awesome repair skills btw, I wouldn't have thought to alter the circuit to get AT working. Might try that on mine as well
I have the same synth. If I use the pitch bend upwards it wont reset to the middle anymore. The spring is somehow dislocated. Can you somehow help me? I need to find out how the spring should be placed. Awesome video. Great content.
I've owned a few JX-8Ps, I've found that they both suffer from stuck keys from time to time. I'm not a huge fan of the keyboard action either, it's okay but not outstanding IMO. I don't think there is any unrepaired JX-8P that have fully working aftertouch!
When he says I lifted this pin, at 24:43, what’s happening there? I get the wire bridge but not those 2 other pins. I’m probably doing this in a few days so will probably have the same issue?
Very nice series! Question: what might happen to a 220v 8p or 3p used in north america with 120v system? If this is generally bad, will a simple step down converter work? Thanks for your wisdom!
hello ... how good your videos, I just have a jx8p and I have to do something .. a question, the white keys also have rubber that hold it like the black ones? Some key has a little play, and I don't know if it is wear and tear where it stabs with the iron, or lack of a rubber band. thanks and greetings
Hey Brad, just got an early B-Day present and guess what it is...lol. Was wondering if we could communicate directly on some things. What I should look for as potential problems ,etc . Also would like to get some opinions from anyone on case screw fixes from anyone. I have the skills and the tools. So far they seem to be the worst problems, but seller couldn't tell me much as he just "flipped" it I am pretty sure.. Keybed/buttons and sliders all feel fine, but I haven't put power to it yet and am thinking the 3 leg cord mod would beneficial to it. I do have interior pictures from the seller, I perused endlessly, which with good comm. from seller decided I should go for it. Needless to say, I will be watching your vids on the 8p plenty and am hoping I can add it to my few "keepers" ,list which has a whopping population of 2. I'll get it open and clean before I send any further messages but ya'll get at me about this and Brad just say ya or nay on private comm. between us. I am in the southern USA, TIA!
I know I'm late, but do you have a picture of how the mod/pitch bend is set up? I bought a thrashed jx8p and cannot for the life of me find how this little mini board with the mod button fits in
The value slider on my old D10 does the 0-99 in one go thing. I replaced the slider and the problem remains. Looking at the schematic for the D10, the slider feeds an op-amp, which I think could be faulty.
There was a fix for the JX-10 aftertouch problem online, which involved changing a resistor or two. Bet you can’t still find it, and that the aftertouch is similar to the JX-8P.
Hello bradthx. May I know what are the output voltages of the transformer, the orange, red & black. How do I test to see weather my transformer is even working. Thanks
Great job. Wish you lived in the UK, I'd be your annoying friend! I'm getting random note hangs on my 8P - not bad, but the note will hang, then not sound for a few times, then kick back in. Any idea what that might be? Any answer appreciated, lack of answer understood. Thanks!
had this problem on my 8p as well. You can fix it yourself if you are careful. You need to take the keybed out of the synth. Turn it over and watch with the magnifying glass what happens at the three copper strip when you press a key. The middle one is probably not returning properly at its starting position and is not fully in contact with the lower strip. The note off message is not sent. I had to (very gently) bend this middle strip with a small pliers in order to accentuate the bend so it can make a proper contact when the key is depressed. Hope this will help you.
Yeah, that was poor wording by me. I was simply attempting to say that this synth has a DCO as the oscillator clock source, 2x per voice, vs. the analog VCOs found in the Jupiter and early Juno synths. The output of each voice module is indeed analog. Thanks for watching!
@@reginaldbowls7180 the Juno 6 had fully analog VCOs, as there was no patch memory. The Juno 60 and 106, however, had DCOs, as they were analog oscillators that were digitally timed, as they had patch memory and other features that required a DCO, which of course still sound great!
If I may - DCO actually means Digitally Controlled Oscillator, it's in no way a hybrid sound generation module - the same chips are found in Juno 106 - noone claims the 106 is a hybrid one...
please can you tell me the specs for the edit slider? I watched over ad over the video. I see that you put a jumper but I don't understand where? ruclips.net/video/nfg9JVnOtKk/видео.html here I see jumper from second pin form above on the left to bottom pin on the right?
Those small round bridge rectifiers are too small, and run too hot. I've changed them out with ones that can handle higher currents. The cost for a new bridge rectifier is the same as these older parts, but newer can handle much higher currents. Mickey mousing a heat sink for an old bridge rectifier isn't worth it, and can fall off later in life causing other problems. Just put a 5 amp rectifier in and never worry about it again.
@@bradthx Great work! Where did you get the replacement JX-8P sliders? They're virtually impossible to get anywhere and I wouldn't mind hacking mine to get the data slider working again. Cheers
if the rectifiers are running so hot why on earhth dont you just massively overspeciry/overate the 1A rectifiers and put in a seprerate bridge of eg 5 amp 100V each single set of 4 diodes as they would only cost pennys compared to value of the synth. why take a risk of only useng minimal rated 1A bridge rectifier whhen a set of 4 5A 100V diodes are so cheap. ?
@@bradthx hi, just ben watching part 2 and see that you have done what i would have done right from the onset, except im a cr*p repair engineerr and wouldnt have a clue how to repair a synth, i just know the obvious basics, such as i would always use an over specified device for all my electronc needs eg if i buy a backup power supply for my many synths i would always get he highist rated power supply i could find, puley for safty. so keep up the good work. i find your videos very enlghtening and imformative. and i had no mtive/desier to diss you in any way. cheers and best whishes.
I've had two JX-8P's, I had a pretty clean one I bought back in 2003, but it kinda sounded a bit cold, boring to me. I think I paid about $400 for it, and slightly more for the PG-800. I sold the JX for about $550 and the PG for I think $800 it so around 2005.
But a year ago I found a totally mint one locally. One owner, classically trained pianist who hasn't used it for years. I took it out of the box, switched it on, everything worked! I used the iPG-800 app for a while to program it, but once I got used to editing on the machine, I found it almost as good.
Funny thing, my old JX has the names of the patches on the keys (supposed to be older ones), whereas my new one doesn't (supposed to be newer) but mine was made in December '85, so go figure.
This model also sounds much, much better to me, I didn't know if it's changed or if I've changed, but the new one sounds very warm and fat.
Being totally ignorant on electronics, I watched your video with sheer awe and fascination. It takes someone with incredible discipline and a deep sense of curiosity to master the complex (to me) world of electronics.
I have a JX-8P that I’ve had since purchasing in the mid-80’s and which has sat in my basement (dry and fairly dustless, cool environment) since the late 90’s.
I recently brought it up to fool around with and surprisingly, it still worked. The patches all work and sound fine although there is a noticeable, constant buzz. I plugged in the PG-800 to it and that worked too.
There is an electronics synth repair place nearby (I’m in SoCal) but because they cater mostly to “rock stars” (as evident by the amount of signed 8x10 endorsement photos in the walls), their repair prices are steep and the wait is in months. That’s not to say that I don’t appreciate ir value the amount of tech troubleshooting/parts acquisition that’s involved. It’s just difficult to balance the justification.
In any case, thanks for posting this! I may not have learned how to fix mine, but I have a better understanding of its components under the hood.
This is my new favorite channel. Ive seen all your videos and you have got me back to enjoying bench work/restoration and synths after a long sabbatical . Keep it up! Greetings from Sin City.
Get an iPad and the IPG-800 app and any Roland synth that uses external PG programmers can be controlled from it!!! Well worth a look
DCO is a Digitally Controlled (Analog) Oscillator. No one should classify this as a hybrid synth.
Rather than using a voltage to set the frequency of the oscillator, it uses a timing pulse from a microcontroller or dedicated timing chip. After that, everything is analog wave shaping.
There's also a whole lot of non-discrete circuitry on these synths. Maybe you meant through-hole?
The JX-8P Sounds fantastic.
So glad I came accross this channel...I also have a 27mhz SSB cb radio addiction...both deal with oscillators filters etc. About to pull apart mt Roland Fantom XA apart to replace the 4 real time 10k pots but am having trouble finding replacement 10k pots at a reasonable price...
Wicked job as usual! Very cool of you to mock up that heatsink to help with the overheating problem. Very intuitive of you. Looking really forward to part 2 and all your future videos. These are my treadmill past time! =)
I know this is an old video, but thank you for saving this synth. Somehow I feel like we have to keep these old synths working for as long as we can. When they are gone, that's it.
I used to love my JX-8p for the killer pads! OMG it was so good at those but yes the display voltage control ran so hot it de-soldered it's self and burnt up the traces, I kept fixing and fixing it! I perfected a Han Solo style fist thump near to the display that would bring it back to life when it failed! :D
Waiting for it to reboot 8...7....6....5.... was a heart stopper if you used it live!
@bradthx - I know it's been almost a couple of years since you posted this, but seriously - THANK YOU. Your series are super detailed, easy to understand, and just top notch tutorials. You've given me the courage to pull my own JX-8P apart and attempt some repairs (keybed is acting up, need to replace a broken key, aftertouch is shot). Thanks again!!!!!
Nice series you did on this synth. My JX-8P is exhibiting the aftertouch issue as well, and the data slider while not completely out isn't working exactly precisely either - may just be a case of it being dirty. I also have several keys where the notes won't come on or they get stuck on. Been using it as a tone module with another controller but I think maybe I'm going to have to open mine up and clean it up and fix it up - I also have a Juno-106 that has an issue on voice #5 so need to fix her as well. Ironically my JX-8P also has the faded off paint next to the volume slider and it was like that when I got it - maybe it belonged to the same family yours came from? LOL who knows. Otherwise mine is in fairly good shape cosmetically (I got mine back in 1993 sometime for around 500 bucks).
Love your heatsink solution. Looking forward to pt 2!
It actually has DCO not digital oscillators. A DCO is different from a digital oscillator in the fact that a digital one produces its sound from a digital sample of a waveform. A DCO is an analog oscillator that is controlled by digital circuitry. The digital half is only there to stabilize to tuning of the oscillator.
Great video! What did you use to clean it? Thanks
I also got an 8P cheap also because of similar issues - a friend helped me replace the bridge rectifier and it's mostly running ok the past years since.
It still has not such great condition slider pot's, and missing headphone jack, too.
Can you recommend what I would search for to find the aftermarket suitable fader pots?
Can def recommend iPad iPG800 app for controlling the parameters!
Wow 🤩 so amazing detail on ur work to fix that awesome beauty! 👍 right on!
Thank you for your video. I'm facing some issues with the parameter and volume potentiometers. Would you be kind to share were you got the sliders?
Good video. Like you I'm an electronics engineer with a love of synthesizers since I was a kid so back to the mid 70's. I've also bought faulty a juno 106 which I need to repair and add a kiwi 106 upgrade to. Also bought a good JX8P which the aftertouch doesn't work on and also have a kiwi JX8P kit to add to that. Your video has let me know what to look forward to inside the unit and good advice on the PSU. Off to watch part two now.
The Kiwi patch editor looks quite good, yes they are expensive but can be used with quite a few synths, just thought I would mention it for people who do not know about it. I'm enjoying your videos, only just came across them, now I have another resource for repair info.
I’ve Just purchased one, here in September 2021. Fully functional with Roland soft bag, foot peddle and two tier stand, $225. Still can’t believe it. Couldn’t really afford it, but couldn’t afford to not buy it either. A once in a life time opportunity.
Absolutely fantastic deal.
This is great, can't wait for part two! A funny note: I think I've got the "brother" of your JX-8P as they were auctioned together by the same eBay seller. Mine is in a slightly better shape, but with several dead keys. I'm learning a lot from your videos, please keep posting : )
That's awesome! I had seen that other synth had sold as well, it had the same worn paint near the volume slider as this one.
The worn paint on the left hand side is common
Thank you for a great video :-) I just bought a JX-8P together with a PG-800. Unfortunately the PG-800 controller does not work no matter what I do, the synth seems to work all right. The previous owner said he haven't used the controller for 20 years. How big of a chance do you think it might just be the din cable that needs to be replaced? The synths and the controller looks in good shape.
nice video, noticed the graphics are slightly different than on my JX-8P. Super nerdy observation LOL. The patch number is in the centre of the button., on mine it's on the left
I’ve watched several demonstrations of the 8P on RUclips, not to mention one or two other refurbishment examples. It was worth clicking on this one only for that instance at 25:54 when you test the data slider and use it to control the filter cutoff. I don’t think I’ve seen anyone demonstrating the edit parameters of this synth on the front panel, just with the PG-800 or some other third-party controller.
Do you have the schematic for this and where did you find the full wave bridge rectifier for this thing? My 5 volt supply is out. I guess I'm building it for now. Nice video man!
I am glad you are pointing out that the bridge rectifier is running near it's thermal limits. I have MKS-70 (2X jx8p) and it does get very hot inside. Perhaps upping the rating on the rectifier?
DCO is not really digital. It has IC counters that divide CPU clock to re-trigger the generation of saw wave core oscillator which is analog (capacitor discharging/charging cycle). It also sends signal to increase/decrease amplitude of the wave. Wave shaping (analog) happens after that
Yeah, that was poor wording by me. I was simply specifying that this synth has a DCO based oscillator source vs. analog VCO oscillators found in the Jupiter and early Juno synths. As for the rectifier, I did actually up it to a 6A unit mounted to the heatsink, will be in part 2 that I should get upload soon. Thanks for watching!
@@bradthx I don’t believe any Juno synths have had anything but DCO’s in them?
Jupiter's all had VCOs but Junos allhad DCOs
Hey brad I have done similar repairs to my JX8P but have two issues. One is sometimes hanging notes that occur occasionally and notes that don't sound that is not the same note. Seems possible it may be keyboard scanning may be overwhelmed or have fault. Any suggestions?? I did the after touch repair the hard way and seems to be still working ok but really like your solution and will implement your bridge rectifier cooling solution. looks cool .
Seems like a really common issue on the JX-8P. I had one 20 years ago with stick keys, hanging notes, so does the new one I just got. I suspect it may be something dirty or corroded inside that's causing it
Congrats by another great video. Looking fwd for the part 2. Happy 2020 !!!
@bradthx Thanks so much for making this! You helped me troubleshoot the power supply on my JX-10 when it suddenly quit powering up. Luckily everything checked out and it just seemed to be a loose connection. Awesome repair skills btw, I wouldn't have thought to alter the circuit to get AT working. Might try that on mine as well
I have the same synth. If I use the pitch bend upwards it wont reset to the middle anymore. The spring is somehow dislocated. Can you somehow help me? I need to find out how the spring should be placed. Awesome video. Great content.
I've owned a few JX-8Ps, I've found that they both suffer from stuck keys from time to time. I'm not a huge fan of the keyboard action either, it's okay but not outstanding IMO. I don't think there is any unrepaired JX-8P that have fully working aftertouch!
Same issue with the potentiometer here ;) with your advice i get it right ! Thanks ! I changed the foor, lot of rewiring work...
When he says I lifted this pin, at 24:43, what’s happening there? I get the wire bridge but not those 2 other pins. I’m probably doing this in a few days so will probably have the same issue?
Very nice series! Question: what might happen to a 220v 8p or 3p used in north america with 120v system? If this is generally bad, will a simple step down converter work? Thanks for your wisdom!
Thank you so much. You are the man.
I wonder if the little CPU heatsinks that are often bundled in Raspberry Pi kits are a good match for the bridge rectifier just going on size?
What spray did you use to clean off the surface? Just curious!
Yeah, I’m curious too. My membrane buttons haven’t been cleaned in at least 30 years and I’m hesitant to use any type of chemical.
Are you still interested in acquiring a Roland xp-80? I remember you saying you had the 50 but wanted the 80.
I have one of these and i have noticed that the scews
underneath the unit get hot around 40 degrees C ish
is that normal.
hello ... how good your videos, I just have a jx8p and I have to do something .. a question, the white keys also have rubber that hold it like the black ones? Some key has a little play, and I don't know if it is wear and tear where it stabs with the iron, or lack of a rubber band. thanks and greetings
Hey Brad, just got an early B-Day present and guess what it is...lol. Was wondering if we could communicate directly on some things. What I should look for as potential problems ,etc . Also would like to get some opinions from anyone on case screw fixes from anyone. I have the skills and the tools. So far they seem to be the worst problems, but seller couldn't tell me much as he just "flipped" it I am pretty sure.. Keybed/buttons and sliders all feel fine, but I haven't put power to it yet and am thinking the 3 leg cord mod would beneficial to it. I do have interior pictures from the seller, I perused endlessly, which with good comm. from seller decided I should go for it. Needless to say, I will be watching your vids on the 8p plenty and am hoping I can add it to my few "keepers" ,list which has a whopping population of 2. I'll get it open and clean before I send any further messages but ya'll get at me about this and Brad just say ya or nay on private comm. between us. I am in the southern USA, TIA!
Nice work.
I know I'm late, but do you have a picture of how the mod/pitch bend is set up? I bought a thrashed jx8p and cannot for the life of me find how this little mini board with the mod button fits in
The value slider on my old D10 does the 0-99 in one go thing. I replaced the slider and the problem remains. Looking at the schematic for the D10, the slider feeds an op-amp, which I think could be faulty.
Do you know the reference of the slider that you put to buy it? or where to look for it?
Love this channel. Your house must be cool.
I recall there being a Behringer option to replace the PG200 but I cannot remember the model
There was a fix for the JX-10 aftertouch problem online, which involved changing a resistor or two. Bet you can’t still find it, and that the aftertouch is similar to the JX-8P.
My part3 video goes over the aftertouch fix, probably the same as you are describing for the JX-10. Thanks for watching!
Do one on JP-8080
Hello bradthx. May I know what are the output voltages of the transformer, the orange, red & black. How do I test to see weather my transformer is even working. Thanks
Orange - orange should be around 12VAC, then around 40VAC across red - red or 20VAC between black and either red.
thermocouple or thermister?
Great job. Wish you lived in the UK, I'd be your annoying friend! I'm getting random note hangs on my 8P - not
bad, but the note will hang, then not sound for a few times, then kick back in. Any idea what that might be? Any answer appreciated, lack of answer understood. Thanks!
had this problem on my 8p as well. You can fix it yourself if you are careful. You need to take the keybed out of the synth. Turn it over and watch with the magnifying glass what happens at the three copper strip when you press a key. The middle one is probably not returning properly at its starting position and is not fully in contact with the lower strip. The note off message is not sent. I had to (very gently) bend this middle strip with a small pliers in order to accentuate the bend so it can make a proper contact when the key is depressed. Hope this will help you.
love your videos! thanks for sharing
The oscillators are analog... they're just timed digitally.
Yeah, that was poor wording by me. I was simply attempting to say that this synth has a DCO as the oscillator clock source, 2x per voice, vs. the analog VCOs found in the Jupiter and early Juno synths. The output of each voice module is indeed analog. Thanks for watching!
@@bradthx Juno synths ALL had DCOs.
@@reginaldbowls7180 the Juno 6 had fully analog VCOs, as there was no patch memory. The Juno 60 and 106, however, had DCOs, as they were analog oscillators that were digitally timed, as they had patch memory and other features that required a DCO, which of course still sound great!
@@agoushy74 Juno 6 has an analogue oscillator under digital control, too. Hence DCO.
@@agoushy74 Hmm? Juno 6? VCO?
If I may - DCO actually means Digitally Controlled Oscillator, it's in no way a hybrid sound generation module - the same chips are found in Juno 106 - noone claims the 106 is a hybrid one...
I misspeak once and have a hundred people telling me about it :) Thank you for watching!
@@bradthx Hey, did not mean no harm, apologies, your work and all your words are absolutely fab, sir! ;-)
Brad: clone yourself and move to Australia - you'll make a fortune!!!
please can you tell me the specs for the edit slider? I watched over ad over the video. I see that you put a jumper but I don't understand where? ruclips.net/video/nfg9JVnOtKk/видео.html here I see jumper from second pin form above on the left to bottom pin on the right?
Those small round bridge rectifiers are too small, and run too hot. I've changed them out with ones that can handle higher currents. The cost for a new bridge rectifier is the same as these older parts, but newer can handle much higher currents. Mickey mousing a heat sink for an old bridge rectifier isn't worth it, and can fall off later in life causing other problems. Just put a 5 amp rectifier in and never worry about it again.
I actually ended up doing just this, will be seen in part 2 which will be up soon. Thanks for watching!
@@bradthx Great work! Where did you get the replacement JX-8P sliders? They're virtually impossible to get anywhere and I wouldn't mind hacking mine to get the data slider working again. Cheers
if the rectifiers are running so hot why on earhth dont you just massively overspeciry/overate the 1A rectifiers and put in a seprerate bridge of eg 5 amp 100V each single set of 4 diodes as they would only cost pennys compared to value of the synth. why take a risk of only useng minimal rated 1A bridge rectifier whhen a set of 4 5A 100V diodes are so cheap. ?
Watch part 2 :)
@@bradthx hi, just ben watching part 2 and see that you have done what i would have done right from the onset, except im a cr*p repair engineerr and wouldnt have a clue how to repair a synth, i just know the obvious basics, such as i would always use an over specified device for all my electronc needs eg if i buy a backup power supply for my many synths i would always get he highist rated power supply i could find, puley for safty. so keep up the good work. i find your videos very enlghtening and imformative. and i had no mtive/desier to diss you in any way. cheers and best whishes.
No worries Carl, thanks for watching!
@@bradthx cheers mate love your videos, will now click the sbscribe button.
I know you're a pro but your random touch of those PSU caps made me cringe a bit. Great video.
you sold a synth? doh!
lol, right? Never do that.