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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Mon Apr 09, 2012 5:55 am Post subject:
Roland "Planet S" MKS30 Subject description: Which voice is sounding now? |
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I've got one of these, and I'm always saying I'd like to restore an old synth. Well, this is as close as I can afford for a while.
It starts up okay, sound output, just some missing notes/notes out of tune, when you press more than one key at a time.
I'm gonna start by re-capping some of the larger caps, and I'd love any links to schems etc. that anyone out there might have.
It's actually really nice, it's the rack mount version of the JX3P. First to have DCOs into VCFs, VCAs, etc.
And everything sits across a stereo BBD chorus. I'm sure that could be extended, modded in some other way/s. _________________ What makes a space ours, is what we put there, and what we do there. Last edited by Uncle Krunkus on Sun Apr 22, 2012 6:19 am; edited 4 times in total |
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DrJustice
Joined: Sep 13, 2004 Posts: 2114 Location: Morokulien
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Posted: Mon Apr 09, 2012 1:48 pm Post subject:
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Schematic here.
I have a Planet S too, and it's indeed a charming little synth. Good luck with the restoration!
DJ
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Uncle Krunkus
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Posted: Mon Apr 09, 2012 6:08 pm Post subject:
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Thanks heaps for that DJ!
"A friend in need's a friend indeed.
A friend with (schem's) is better."
As well as being a godsend for the little issues that need fixing, it also makes the whole process a lot more edumacational!
It is a great little synth, and it has the best of both worlds, so I'm wondering why I haven't been motivated to sort it out yet. I've had it for well over 3 years, and don't hook it up because of this note problem. Maybe I just know more now, or have more confidence to take it on.
I'll keep this thread up to date with my progress whenever I can. _________________ What makes a space ours, is what we put there, and what we do there. |
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Dougster
Joined: Sep 20, 2005 Posts: 272 Location: Tucson, AZ, USA
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Tue Apr 10, 2012 4:12 am Post subject:
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I've started checking out the PSU. Unfortunately, those schems don't include the PSU, and I can't find any that do include the PSU.
On one of the power connectors, CN2, I've got 11V9 on the 7V rail.
I'm really not happy about that. But I'm unsure whether it is something to be worried about or not.
The +15 is +14.4, -15 is -14.35 which is okay I s'pose, but it is 4% out isn't it? Surely it could be improved, but I don't see any kind of adjust.
The 5V rail seems to be rock solid on 5.0V
All these voltages were read with the connector disconnected, ie: no load. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Tue Apr 10, 2012 5:58 am Post subject:
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I'm not worried about the "7V" rail now. It's an unregulated tap off the input to the 7805 regulator. Just diodes and the main ripple cap, so with no load it would be high anyway. I traced it to the front panel write protect switch, so I'd say it just needs to be at least "7V" in order to flash the cartridge memory.
(edit) I've since realised that this "7V" rail also goes to the PG200 controller connector, so I'm assuming it would be regulated inside the programmer? Which would easily need another power feed like this one.
So, doesn't look like any major faults in the PSU. I'll re-cap it when I get the caps, though. _________________ What makes a space ours, is what we put there, and what we do there. Last edited by Uncle Krunkus on Tue Apr 24, 2012 3:32 am; edited 3 times in total |
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infindebula
Joined: Sep 29, 2011 Posts: 29 Location: Canada
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Posted: Tue Apr 10, 2012 12:42 pm Post subject:
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You do realize that unlike the JX-3P, the MKS-30 uses the dreaded (and revered) 80017 VCF/VCA hybrid, right? That's the same component that causes missing/crackly notes in the Juno-106.
There are tutorials on removing the resin coating from those (it becomes conductive over time) to resolve the dead notes. There is also a clone of that hybrid IC available (try googling "D80017"). |
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Uncle Krunkus
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Posted: Tue Apr 10, 2012 2:39 pm Post subject:
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Oh yeah, I'm aware of that little gem!
This thing's got 6 of them, all stacked up and ready to go (faulty! )
My first gut reaction was that I might even have to lose one and go back to 5 note polyphony.
Thanks heaps for the heads up though infindebula. I didn't know they could be "stripped", and, I assume, repaired. I've read about the replacement/clone before, so I s'pose that could be an option.
But first I need to work out exactly what's happening. It's as if the faulty note interacts with ones which are already sounding.
Actually, the first thing I need to do is power it up and do a full investigation of the symptoms, cos I remember it being quite unpredictable in what would happen when the faulty voice(?) activated.
I'll get into a test session today or tonight hopefully, and report back. _________________ What makes a space ours, is what we put there, and what we do there. |
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infindebula
Joined: Sep 29, 2011 Posts: 29 Location: Canada
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Posted: Tue Apr 10, 2012 3:02 pm Post subject:
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Hehehe... yeah I used a Juno-106 as a "donor" a few years ago to repair 3 others (which I flipped). So now I have a Juno 106 with no 80017's - I threw out the failing ones when I was cleaning house. About a year later I read that people have started soaking them in acetone to remove the coating and the trouble goes away! Needless to say, I'm pissed.
There's even an ebay vendor who keeps offering the service of removing the resin (for significant $$$ though)
Even if you resolve the problems by other means, as long as you have your Planet apart you might do well to strip those modules in any case, to help ensure its long-term reliability.
Good luck! |
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Uncle Krunkus
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Posted: Tue Apr 10, 2012 4:54 pm Post subject:
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Thanks for that,
I'll look into it, though I must admit that successfully de-soldering 6*11pin rare slabs of IC and soaking them, and getting them all back in, without doing any further damage,........ is not something I'd be looking forward too!
But, I've got plenty of time, so if it comes to that, I'll see it as a challenge.
I've noticed that there are pads in place for bypass caps to be installed on almost every digital chip, but none were ever installed. Would it be a worthwhile job to put them in? Or just a waste of time?
I've done a basic test, and it seems that all 6 voices are working. The most obvious issue is that on every patch there is a note sounding without any key depressed. This could be that one of the ADSRs is being held up. Or it could be a symptom of a dodgy 80017 which just needs a bath. I think the ADSRs are in the 80017s, but I'll have to check that.
There's also a scratchiness associated with that held up note, which is worse on some patches than others.
So, overall, it's looking quite good really. _________________ What makes a space ours, is what we put there, and what we do there. |
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infindebula
Joined: Sep 29, 2011 Posts: 29 Location: Canada
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Posted: Tue Apr 10, 2012 7:01 pm Post subject:
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Uncle Krunkus wrote: | successfully de-soldering 6*11pin rare slabs of IC and soaking them, and getting them all back in, without doing any further damage,........ is not something I'd be looking forward too! |
If it's not something you're comfortable doing, then you most certainly shouldn't! The key to desoldering is having the right tools. For plated thru-hole boards you most certainly need something that sucks solder. At home I do OK with a bulb iron like this, but for serious stuff I am fortunate to have one of these at my work.
Uncle Krunkus wrote: | I've noticed that there are pads in place for bypass caps to be installed on almost every digital chip, but none were ever installed. Would it be a worthwhile job to put them in? Or just a waste of time? |
Hmmm... probably couldn't hurt, but if they were never there, it wouldn't likely make any difference. I don't have a schematic, but if they are in the wave shaping section, you might even get slightly better-sounding square waves or cross-mod as a result.
Uncle Krunkus wrote: | on every patch there is a note sounding without any key depressed. This could be that one of the ADSRs is being held up. Or it could be a symptom of a dodgy 80017 which just needs a bath. I think the ADSRs are in the 80017s, but I'll have to check that. |
The ADSRs are not in the 80017s, but the VCAs are. I believe the ADSRs are software.
Uncle Krunkus wrote: | There's also a scratchiness associated with that held up note, which is worse on some patches than others. |
That is the part that sounds like a bad 80017, or perhaps a bad VCA trimpot. |
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Uncle Krunkus
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Posted: Tue Apr 10, 2012 8:52 pm Post subject:
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Oh I'm comfortable with doing it. It's just not a job I'd take on lightly.
I've done quite a bit of fine work before (I'm also a model maker), and working patiently and precisely is what I do best. But because of the concentration needed, I like to prepare well.
I've de-soldered chips before, but I only have a solder sucker, and solder wick. I'm sure these ICs would be quite heat sensitive, so it would be good to insure a consistent and hassle free approach.
I suppose adding a few bypass caps at the re-capping stage might be worthwhile. I'm thinking the replacement of all the 30 year old electrolytics will have a lot more tangible result on the crispness of squarewaves. I met someone who completly re-capped a Korg M-1 about 2 years ago, and he raved about the sudden jump in clarity and sparkle. "like a brand new synth" he reckoned. _________________ What makes a space ours, is what we put there, and what we do there. |
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DrJustice
Joined: Sep 13, 2004 Posts: 2114 Location: Morokulien
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Posted: Wed Apr 11, 2012 3:01 am Post subject:
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infindebula wrote: | The ADSRs are not in the 80017s, but the VCAs are. I believe the ADSRs are software.
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That's correct. Both ADSRs and LFOs are software .
Very interesting info about those replacement VCA/VCF ICs. I haven't powered up mine in a while so I hope the ICs are fine - if not I'll try the acetone method before buying new ones at EUR 40 a pop (six needed).
DJ
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Uncle Krunkus
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Posted: Wed Apr 11, 2012 5:24 am Post subject:
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Okay,
The board is actually laid out in a very logical way. The analogue (80017s) section goes down the left hand side, and the summing resistors which lead across to the HPF are easy to find. I hooked up a cap and resistor on a phono lead and had a "listen" to the 80017 side of these summing resistors and described the 6 outputs like this,
Silent
Soft
Loud
Just scratchy
Silent
Soft
Then I checked the same points on the scope referenced to AGnd and got this (p-p),
0V
50mV
20V
20mV
0V
30mV
So, not only do we have a good match, (shows the power of the ear as a test tool) but the prime suspect is fairly obvious.
These tests were all done with no keys depressed. No note events happening.
Before and between the tests, I pressed a few keys, changed the patch, and tested again, the results were the same. I did this because I wasn't sure if the fault could be in the software, and/or if the analogue voices were assigned sequentially, or on a first come, first served basis. The unwanted signal levels stayed on the same analogue sections each time. I think that pretty much guarantees that I have some dodgy 80017s, and or trimpots in the analogue sections for each one.
There are 4 trimpots associated with each 80017. RESO-POSI-GAIN-DCBAL
I'd like to find the service notes so I could learn about calibrating these. If they are scratchy etc. it would probably show up in that process.
But,......
Maybe I just need to pull that 80017 out and buy some acetone! _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Thu Apr 12, 2012 12:46 am Post subject:
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Well,
I've had a very adventurous afternoon.
I now have 4 * 80017s desoldered and sitting in a bath of acetone. Well, it's nail polish remover, which is 80% acetone. Before everyone starts going "nail polish remover has oils in it! don't do it!" I could only do pure acetone if I waited till Saturday, and it would be $20 for 100ml! The nail polish remover was only $5.95 (no, I don't have a job. ) Once it's eaten the black stuff, I can wash the boards off with isopropyl alchohol, which I have plenty of. It will remove all the oils, and will eveaporate completely.
De-soldering the 80017s was okay. I found the best way was to just load all the pins up with heaps of solder, and run the iron back and forth while levering the module out with a screwdriver from the edge of the board. It sounds brutal, but actually ended up being the most effective way. Solder sucking, and wicking the pins helped to get some free, but just getting it out fast felt heaps safer.
After it's out, solder sucker, wick, and even drill away, the pads are pretty easy to prepare. I had one pad lift, I'll just create a bridge when the 80017 goes back in. Scrub with PCB cleaner, and the positions look great.
The chips are just sitting there in the bath.
Another 24hrs should give me some results.
BTW I know some of you are thinking, "why just 4? Once you've got 4 out, you may as well get the last 2 out!" But I'm a bit of a "let sleeping dogs lie kinda person." i.e.- I'm lazy! )
More later. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Fri Apr 13, 2012 4:08 am Post subject:
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Okay,
Well I succumbed to completionism and pulled all 6 80017s. And I might say that I'm feeling pretty full of myself too!
The last two, (which, as far as I know, were working perfectly) I simply covered in solder and yanked 'em out like sore teeth! This took about 30 secs each, as compared to farting around with solder-wick, then solder sucker, try to get a definite release of one pin at a time, method, which often ended in a "drown it in solder and "out you come, you little!!?!"" anyway.
Like you said infindebula, the right tools make a helluva difference. But even with basic means, you just gotta get a feel for the least intrusive method. It's almost like surgery. The medicinal practices oath goes back to ancient Greece. "At the very least, you should do no harm"!!
Desoldering these kinds of chips definitely flies close to crossing that limit!
Anyway, the board is completely drilled through with a .7mm bit, and cleaned with iso to get rid of all the rosin and old circuit board lacquer. (They laid that stuff on with a trowel! It's like cleaning up glue!)
4 of the 80017s have been soaking for over 24hrs, and most of their gunk is lifting and turning to a parmesan cheese consistency. I think it will be a fairly straight forward task to remove it all. Time consuming, detail stuff, which I love. Just use a scalpel blade, and heaps of patience. The last two I took out this arvo, so they've only been in for 5-6 hours.
I've ordered all the smaller electrolytic caps, and have a set of about 25 monolithic 100nF caps for all those empty bypass positions. This is gonna be a great synth, AND a work of art as well!
I haven't even started looking at all the possible mods I could do. Larger BBDs in the chorus section? Any other ideas? _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Fri Apr 13, 2012 8:35 am Post subject:
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I've installed all the missing bypass caps.
Something I learned in the process was that when you want to clear a via which has been filled in the bath process, you should heat at the front first, then go to back and heat the same via, then solder sucker from the front. I couldn't clear these vias at all (being bypass caps, they are all across the heavier power tracks which suck heat away really fast) but once I tried this sequence,.... perfect, every time. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Sat Apr 14, 2012 12:59 am Post subject:
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Are there any reports of success with socketing these 80017s?
I'm just thinking it would be a shame to solder them in and then find that there was still an issue with them. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Sun Apr 15, 2012 8:23 am Post subject:
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Well, I ended up putting 6 sockets in for the 80017s.
Be really careful with the amount of heat you put into these modules. Too much will desolder the pin from the ceramic substrata. I think I managed to solder the three of them back, but I won't know until I do a test.
In fact, straight after peeling the black crap off around the pins, I'd recommend carefully scrubbing the back of the pins with a toothbrush, and then cover them with a small amount of superglue. The crimps on these pins don't even oppose each other.
Apart from this, everything has gone well. The sockets seem to be really sturdy, and have a tight grip on these antiquated pins.
I still need help trying to calibrate these modules dudes!
I'm just waiting on the electrolytics, and then I'll be ready to test it. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Fri Apr 20, 2012 9:20 am Post subject:
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First test tonight of the overhauled board.
I've replaced the two main PSU caps (were 4700uF 35V, now 4700uF 63V (newer version fits quite well))
And most voices are a lot better than they were.
None are sounding all the time. Big bonus!
But,.....
The position for voice 2 on the Main board always results in no sounding, and the 80017 getting hot, quite quickly. Swapped out, they work fine, but the one in Pos 2 always gets hot quick!
The other issue, is a kind of uncontrolled portamento/vibrato on at least two of the voices. Might be an interesting feature, but I'd prefer to be able to shut it off. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Sun Apr 22, 2012 6:17 am Post subject:
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Well,
the socket I put into postion 2 (Voice 2) on the main board, had a micro fine (1/10th of a hair) solder web across it from the desoldering/socket soldering. Fixed that and position 2 seems to work fine now.
Now it seems like one of the 80017 modules is faulty, but I don't seem to be able to prove which one!
It's like the voices are being assigned sequentially, so if you press more than 1 note at a time, the note to voice arrangement cycles around in some way.
This is what I was talking about further back in the thread.
I saw a youtube vid where they set it up so the display told you which voice was currently sounding, but that was using a Juno106. Does anyone know how to do the same thing on an MKS-30?? _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Sun Apr 22, 2012 7:02 am Post subject:
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I found the procedure for getting a visual on the current voice soundings.
It's here :-
http://mamonu.weebly.com/roland-mks30.html
So that has brought me to the conclusion that 1 module is faulty, and all positions (on the main board) are working. 2 of them have this strange vibrato/tuning problem, but I assume that will have to do with calibrating the trimmers. Or something else entirely.
The faulty 80017 is the one on which I resoldered 3 pins, which let go of the ceramic substrata in the cleaning process. I'm not sure how to fix these pins, as it seems the conductor on the chip is really hard to solder to. It seems to shine up with a scalpel blade, but dulls again really quick when you try to solder to it. The joins just crack off. It seems to have a green board lacquer of some type, but I thought I'd scraped that off. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Joined: Jul 11, 2005 Posts: 4761 Location: Sydney, Australia
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Posted: Tue Apr 24, 2012 2:30 am Post subject:
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I'm kinda unsure where to go with this now.
Do I just accept that one 80017 is cactus and save up so that I can afford to get a replacement? Try to troubleshoot and fix this one?
I still need to do a test with the bad module pulled, and see if the glide/vibrato fault is still there. I could work on eliminating it if it's not in the module, but I'd still end up with a missing voice. Could be interesting for an arpeggio, but difficult for anything else.
I might point some of the big guns at this thread and see if there's any ideas. _________________ What makes a space ours, is what we put there, and what we do there. |
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Uncle Krunkus
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Posted: Tue Apr 24, 2012 4:58 am Post subject:
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I did the test and found that the vibrato effect is on board positions 4, 5 and 6. I rotated all the modules around, and still, it's on 4, 5, and 6.
So, straight away, I've removed the faulty 80017 and made the empty position 6. That gives it the best playability it's had for a long time, 3 steady notes!
Now I have to work out what is creating this vibrato on the main board. _________________ What makes a space ours, is what we put there, and what we do there. |
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EdisonRex
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Joined: Mar 07, 2007 Posts: 4579 Location: London, UK
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Posted: Tue Apr 24, 2012 10:36 am Post subject:
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Wow, you've been industrious.
I don't know enough about this board but I'll take a look at the schematic. I've dealt with the Korg Polysix more than Rolands of that ilk. Is the vibrato slow or fast? _________________ Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated.
Home,My Studio,and another view |
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