Second opinions on Tech's botched JP-8000 repair?

[bussy233]

cross posting this from elsewhere just to see if anyone has any other suggestions. thanks.

What the heck did this tech do to my synth?​

I bought this JP-8000 off craigslist ~2013. The listing said it had a minor problem but ended up being worse. I did minor repairs prior to another JP, replaced the ribbon controller, maybe replaced a pot etc. When I tested the synth it was LFO'ing etc on it's own, bunch of stuff going on IDK, it sounded circuit bent or something. I was hoping it just needed a slider/pot replaced, the price was good and I already traveled into manhattan and everything so I bought it. I don't think I even opened it for repair, I brought it to Three Wave Music in NJ which is some asian tech guy, back around 2013 I think he focused more on repairs esp vintage stuff and/or reselling them and his warehouse was filled with tons of rare synths, now it's become more of a shop with brand new gear. Anyway, I dropped it off there for a quote. He called me back weeks later saying something like $350. I say ok. A few weeks later he said it needs a board from Japan and would be another ~$300. I said no because it would cost more than a %100-functioning one from eBay. He basically said 'you can have it back still broken but I have to charge the ~$300'. I said the original price was for it to be fixed otherwise I would have said no to a ~$650 total plus like $250 I paid for it, these were ~$550 on eBay fully-functioning and sometimes on craigslist for ~$450, although they all will probably soon need the capicitors replaced which causes low volume/distortion because Roland used low-temp-85C caps, there's tutorials on youtube and 105C capacitor kits on eBay for like $30 which takes the guessing out of which caps to buy for a novice, Edit: actually the blue-led modded JP-8000 video below he installs 105C rated caps but 20,000 hour life vs 5,000 hr like the eBay ones. I need to do this to a different JP I have which works fine except for it developed low volume/distortion. Anyway back to this synth, I said no to an additional $300 and if he wanted to charge me to take it back broken I said I'll call the cops. I would have taken it back broken for no fee despite it sounded like he made it worse. Like 10 months later he gave it back to me 'fixed' for the original price. This whole process with him was horrible, come to find his reviews people say the same, were told a few weeks turned into over a year etc etc. I think he prioritizes more pricey vintage stuff to justify his labor costs otherwise like my situation it doesn't make sense to pay more vs buying fully-functioning used or even brand New but I also read a review of a $3,500 vintage synth that took like a year longer and the guy got screwed.

So I get the synth back, it works, I never dropped it or anything but in about 9 months it stopped working. I turn it on and all the screen pixels are lit up solid and makes no sound through any jacks. I bought another JP8K and tucked this one away until now. I opened the back and saw his hack job with these jumper wires.

Do you think this is fixable if someone here can guide me through? I have a $400 vintage analog multimeter and a cheap digital one but don't really know what I'm doing with either if are needed to see if the main board or something is fried. I'm half decent with soldering. If I fix this, I'd also recap the 85C OEM capacitors like the other one I'm planning to. Maybe better to part this one out on eBay? If I can fix and re-cap this one, clean and re-grease all the keys, would sell for around $1,100 after fees and shipping nets around $850. The main board I hope is fine and sells for $165 used on syntaur parts site I can net around $150 for it even without re-capping but might have to sell as-is for less. The shell I could probably net $150, the bottom shell/plate $50, the keys net about $300 total, pitch bender $40, jack board $50, transformer power supply board 3 parts total nets about $125 and they are all hard to find most the stuff on syntaur are Used and out of stock or only 1 left. Net $5 each knob cap and slider cap total of ~$175. Total net parted out = ~$850 plus if any of these 3 boards he butchered are still usable they sell used for $50, $75, and $100. Maybe it's a good thing to offer up parts that are discontinued since I don't want two JP-8000s, but I sorta am up for the challenge of repairing this if anyone can guide me through it.

I doubt the original person I bought this from or whoever mighta owned it prior did these jumper wire things, plus threewave probably would have mentioned it. I guess someone originally bumped into a knob(s) or something and caused this although that'd usually just cause ghost editing or something. The circuit board doesn't look cracked anywhere. Any idea how this problem even started with how it sounded circuit bent and LFO'ing pitch etc by itself and considering what the tech did to temp fix it? The transformer has different prongs for 240V, 230V, 120V, 100V but it's properly how it should be for USA 120V, not like someone plugged it direct into something higher.

Here's the blue-LED modded refurbish where he uses 20K hour life 105C caps vs the eBay ones are 105c but 5K hours. I'm gonna make a separate thread about help for that on which 105C caps to buy for 20k hours instead of the eBay 5k hours, but anyway:

says

He listed it for $11,500.00, yes $11.5K on matrixsynth, IDK what he actually got for it though if it sold.

https://www.matrixsynth.com/2020/04/11500-big-blue-roland-jp-8000.html

So, the potential repair. I guess the whole board itself it conductive and the darker lines/areas are not so that they don't conduct or interfere with other parts and just short everything out - that's how a circuit boards works otherwise they'd have to run a powered wire to the every component that needs power plus also wire it to whatever processor etc it communicates with.

There's a very shallow scratch as shown in photo circled with white. Although it worked fine with this scratch so I guess it's not the problem. Can see orange-brown flux on areas he re-soldered but didn't add jumper wires, I compared to my other JP's boards and that one is all clean factory/automated-solder points. The photos with no jumper wires notice he worked on the orange/flux connections. Also see orange flux on some mini series of solder points which leads to a ribbon cable. Maybe he bridged some soldering and shorted things? IDK, and if so I dunno how it worked for 9 months after I got it back.

Why would threewave even add these wires?! All these jumper wires are connected to sliders or knobs which control LFO, portamento etc and normally can just be re-soldered. IDK if he used new replacement knobs, I had the checklist paper he noted everything he did but I discarded it years ago I guess. The solder points look decent and the knobs/sliders he worked on don't wobble but can see at least one seems like a failed solder point.

There's an internal disc battery which dies which stores patches but if dead also makes the synth not work, but I swapped it with the working on from my other JP and it doesn't fix it.

Thanks.

Pics:









https://imgur.com/a/Se7L08A

https://imgur.com/a/y2tz90J

https://imgur.com/a/KdMwFQP

https://imgur.com/a/aacXTfB

https://imgur.com/a/MfHunXX

https://imgur.com/a/oQaNF36

https://imgur.com/a/LAK3IYT

https://imgur.com/a/8QPt3Dz

https://imgur.com/a/ccizokF

https://imgur.com/a/ChyiKyE

https://imgur.com/a/SfRmL8E

 

[bussy233]

the replies (some are me):

Some of the soldering on those jumpers looks pretty dodgy and you might get lucky by reflowing it.

But frankly I (and most techs?) would steer completely clear of this project, too much history, too much blame-game, too many people working on it a little bit, etc.

Recapping can create more problems than it solves, I wouldn't recommend recapping anything until you're absolutely certain the caps are actually causing a problem.


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I agree with [], whomever did that work to the synth did a horrible bodge job. It reminds me of the crap work I used to do when I was learning to solder {cough}ty years ago. If that came from a pro shop there’s no way they could expect to stay in business.

The problem you are experiencing and describing now is most likely related to either the power supply section or the reset circuit or oscillator of the CPU. Randomly replacing parts is more likely to break something else so this needs proper troubleshooting using a schematic/service manual and following the voltages through preferably with an oscilloscope rather than a DMM or multimeter.

Absolutely do not recap your entire synth if you do get it working. Someone somewhere got lucky doing a capacitor bulk swap and managed to fix their (whatever it was, not necessarily even a synth) and that became some kind of thing that you just have to do, whether or not your symptoms relate to a bad capacitor. You are more likely to cause more damage than you fix, if you are even lucky enough to happen to accidentally find and change a couple of bad caps, and from your own skills summary you would have no idea how to proceed in finding and fixing the faults you introduced. Japanese PC boards of that era do not take well to the heat that would be required to desolder the old caps, much less the added stress from soldering in new ones. The adhesive bonding the copper to the substrate was already poor the day they built the boards, and it dos not age well at all. I know this because I used to repair a lot of consumer products made from the late 70’s to mid-80’s. All the missing pads and traces you already have are evidence of the fact that unnecessary rework is going to cause more damage.

Also you will probably throw out dozens of perfectly good capacitors while replacing them with today’s latest technology which is just mediocre by comparison.

I’ve taken on some real dogs for repair, but like Adam, this is not something I would ever put on my bench unless I were parting it out. There is no way of telling just how much other damage there is, and you might not welcome a large repair bill for something that can’t be fixed. It is reasonable and customary to pay for diagnosis even if the repair isn’t carried out, and it’s also reasonable to determine that ordering an expensive replacement board or three is going to cost you way less than the potentially dozens of hours of labor trying to patch that monstrosity back together, including trying to repair or reverse the damage the last artiste caused if that’s even possible. I would never give any kind of warranty on a device some other person butchered because even if I reworked and tried to repair the damage, there’s likely to be more that’s not visible. Plus, vintage electronics, especially from certain eras and manufacturers, are not prone to stay working for very long

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ME:
ok so apparently the jumpers are because circle pads have been removed accidentally from soldering, and someone I trust's experience here said Japanese boards from this era are notorious for such problems so I wouldn't bother even working on it. And IDK if the tech from threewave did this or someone before him but if it were threewave then I'd be even more warry of working on this as that guy is probably a synth-repairing-wizard when he's locked in so for it to happen to him means it's not easy. I still might though try to re-cap the main board as I need that for my other JP with low volume&distortion due to failed caps.

I'll be easier to snap some photos, measure weight and part it out online as-is and still make back about the same amount VS opening a worse can of worms working on it and spending more time than selling plus hopefully I make a lot of people happy with spare parts which are getting very rare. I really wish Roland would made a new version of this synth the layout is my fav of any synth probably. Feedback OSC is great too.

The only suggestion for why it actually doesn't work though was:

The problem you are experiencing and describing now is most likely related to either the power supply section or the reset circuit or oscillator of the CPU. Randomly replacing parts is more likely to break something else so this needs proper troubleshooting using a schematic/service manual and following the voltages through preferably with an oscilloscope rather than a DMM or multimeter.

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It is reasonable and customary to pay for diagnosis even if the repair isn’t carried out,

ME: Absolutely agree, I do this all the time with car mechanic, 'charge me whatever you want to figure out what's wrong and if I think I can do the work following youtube tutorials I'll do it myself otherwise how much for the repair too?' But from what I remember with threewave the diagnosis was free once I OK'd the repair quote. Either way whatever, hopefully all the parts go to someone who really needs them. I love this synth for the layout, the sliders instead of knobs of filter to simultaneously tweak them, can do a lot simultaneously with the left side LFO and Joystick, and the Feedback osc esp on Bass notes and sweeping the 'Harmonics' is really unique.

 

[bussy233]

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ME:
ok thanks I really appreciate the replies. I'll just part it out and not go crazy. It may take some time to sell everything but it's small parts. I can put the main board in my other JP-8000 which developed the common bad-caps distortion/low volume problem to test, this broken one didn't develop the low-volume problem yet when it died, but there's so many fragile ribbon connections to the main board that I'm not sure it's worth messing with, I don't trust the build of this synth, some ribbons aren't pins they're like crimped flat paper thin and then shaved down to expose the aluminum connections I don't want bending when popping in.

I've done a small amount of through-hole soldering replacing pots etc but yes one tutorial about the cap-swap said it's very easy to lift the pads for these surface-mounted and mess up the main board, so I'll probably mail it out to a tech and if I can get it re-capped for like $250 (parts are only like $20) then that's cool, but since I basically have a spare back up I can try it myself. I picked a stereo out of the trash that I can practice a lot on but IDK if there's surface mounts. One tutorial said he went ahead and re-capped everything else on the board, he didn't sound as experienced as another and most others say it's just the caps on the main board, which cause the low volume/distortion as they weren't made to take heat for even only 20 years of average use. So it'd just do the ~20 caps on the main board. All are the same except for 2,

Also according to the eBay seller:

https://www.ebay.com/itm/286077307895

This model is prone to main board failures that cause the sound to become extremely quiet, and there are companies that will repair it by sending out just the main board.

The faulty part is the mute circuit that prevents the popping sound that occurs when the power is turned on and off.

At our store, we have made a modification to deliberately disable this mute circuit (by cutting one of the jumper wires on the interface board).

As a result, the problem of the sound becoming quieter due to a fault in the mute circuit will no longer occur in the future.

However, there are also the following disadvantages.

When turning the power on or off, you will need to make sure that the sound does not come out of the amplifier or mixer (PA, etc.) that you have connected beforehand. (There is a possibility that the amplifier or speakers will break if a loud sound suddenly comes out.)

For those who are familiar with mixer operation or guitarists, it is a normal procedure to turn down the volume before operating the power or plugging in or unplugging the shielding.

If you remove the plate on the bottom of the synth, you can easily access the cut jumper wire and put it back in place.

If you send the main circuit board for repair, you will need to put the jumper wire back in place.

Here's the eBay listings for the re-cap kit, there's 105C is good but only 5K hours not 20 like the blue-LED modded thing I linked he used.

https://www.ebay.com/itm/265940571087

https://www.ebay.com/itm/275647226200

I'm surprised three wave did this, if you google that, check the yelp etc you'll probably be impressed with the shop, He's since moved location and focus more on new gear etc it seems, but when I brought it there and also stopped in a couple times it was just the one ~50 year old asian guy alone and sometimes had like an 18 year old kid that seemed to know nothing about anything just basically watching the shop while the owner worked on stuff in the back rooms. Drove a nice BMW SUV, warehouse full of liek quarter million dollars of gear, some of it customers' though but anyway seemed basically like some guy that really knew what he was doing. Also some to find the screws that hold the board in are not machine screws which screw into metal threads, they screw into plastic threads which is ok if you're careful but this guy takes a wood drill to your synth and he stripped every single screw on the board and it's barely holding, the shells keeps it all together but he butchered this thing.

What was he even trying to do with these jumpers? EDIT: I guess there's missing Round pads on the through-hole connections shown in photos either done by three wave or someone prior (I think if it were someone prior three wave would have mentioned it to me that someone else botched a prior repair) and so he jumped the pins to something else.

All the missing pads and traces you already have are evidence of the fact that unnecessary rework is going to cause more damage.


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The jumpers look like they're intended to replace pads / traces that lifted off the board while replacing parts - for instance:



Just above the right-hand end of the red jumper, you can see a circle of bare fiberglass where there should be a pad.

 

[bussy233]

Ok so likely the problem doesn't have to do with the jumper wires the tech added due to pads lifting off when he replaced/worked on sliders and pots. I think it's the following which was suggested: The problem you are experiencing and describing now is most likely related to either the power supply section or the reset circuit or oscillator of the CPU. Randomly replacing parts is more likely to break something else so this needs proper troubleshooting using a schematic/service manual and following the voltages through preferably with an oscilloscope rather than a DMM or multimeter.

I'm likely going to part it out, as-is for the electrical parts, I guess somehow either and/or the following broke: power supply, reset circuit, or oscillator of the CPU.

I don't have an oscilloscope or know how to use one. I can switch parts out from my other JP8K which has low distorted volume likely due to the caps on the main board. I can swap the power supply, doesn't seem to hard, but I don't want to risk maybe it's overpowered which could fry both main boards etc.

I think I'm just gonna try swapping the main boards if it'll fix the other JP because this one w the jumper wires didn't have low volume/caps problems when it worked. If the OSC CPU is on the main board which I assume, but if it works when swapped to the other synth that that'll mean the problem isn't to do with the main board.


And then I'll have one fully working JP minus a few knobs where the center detents don't click (like a pitch control knob so you know you set it back to not be detuned, not really worried about Pan/OSC balance etc being so exact) but considering several have said this era Japanese boards are notorious for lifting pads I'm not sure I'll bother with it unless things start to ghost edit then I'll replace knobs/sliders and if a pad lifts I can probably just scratch an open area near the connection to expose copper and bend the leads/run a jumper (I'd have to ask online how to do although have done with an MC-505 by bending the pins was suggested IDK if the JP8K's board allows that hence this tech had to run jumpers to other existing solder points, and just hopefully the knob doesn't end up wobbly if the pad lifts but still soldered to the fiberglass or whatever.



And then if it needs to be recapped if the main board swap works, I'll worry about that later and/or try to recap the other one myself instead of selling it for ~$125 net.


I really wish they'd just make a new synth that has a layout as good as the JP, it's crazy that they still haven't despite how pretty much everything else is sub par.