the best place for resources is wayne joness's excellent site,
https://www.joness.com/gr300/GR-700.htm
that dude is both a gentleman AND a scholar.
anyways, i was recently gifted a semi-working gr700 guitar synth with the 24 pin cable, a gr202 guitar synth controller, and a gr300 that just needed an led replaced.
the 700 worked perfectly at first, til i hit a patch with a random sample and hold. at first, i thought the hold pedal function had stuck, but cleaning it had no effect.
so did some research, which led to the 80017a chips being faulty, and that they could well be repairable.
what it is is a couple of dip chips with printed resistors and smd caps on a ceramic substrate thats sealed in a rubbery plastic kinda stuff that in some cases is still gooey inside 40 years later, kinda like the insulation that turned to sticky goo in old japanese guitars or the black foam insulation that would rot into hideous foul goo...
anyways, over time, the stuff becomes more and more conductive til it causes all kinds of weirdness.
supposedly, if you can get it off, the chips will be "restored".
and it does, in fact, work that way.
anyways, the prevailing wisdom is to scrape off some of some of the goop on the top and sides of the chip.
the theory is this will let solvent in to help dissolve the goop. ya soak 'em for a day or so, then start chipping away at it.
to dissolve the goop, use acetone. pour about 4 fingers into a glass jar with a tight fitting lid and set aside for a minute.
anyways, me never being afraid to let the magick smoke outta stuff, decided to see if there may be a better way, for me, i found one. i don't advise you do this, caveats apply, acetone is nasty shit, as is the goop on these... if ya mess it up, mess yourself up, poltergeists start flying out of your television set or whatever, i'm not responsible.
wear gloves and protective glasses if ya do it my way, as shit will be flying off and shrapnel in the eyes sucks.
i took bog standard single edge razor blades and hacked away at the epoxy goop til i could see the white card beneath. i did this on the top of the card, the sides of the card, and as much of the bottom as i could get at. i didn't @#$% with where the pins were coming out.
i used a small file to grind off the rest i couldn't get with the razor blades. i found a single edge was good for about one card. the junos and gr700 use 6 cards a piece. they DID break, and pieces DID go flying in my face, and bounce off my glasses. but i was determined, insane, possibly a bit of both.
once i had clear margins around the chips, with the bumps facing me, i used the razor wherever possible to start lifting the epoxy to chip at least some off.
look on wayne's page at the stripped chips to see where NOT to do this. i didn't, and had to buy two replacements <tho my bassist, jolly roger fixed 'em at work for me>... one where i had sliced one of the smd caps in half ... it still worked...
and the smd caps are 680p @50v by the way, cuz they're not marked on the schematic roland made available...
and another where later, as i was cleaning goo between ic leads, i inadvertantly lifted a leg and f'd up a pad... he fixed that one, too. its what he does.
one more i had actually sliced one of the caps off completely. it still worked, but had a bit of fuzz to the filter on that one string. thats been fixed now too.
so i gotta couple spares... may be handy. also updated it to the newest firmware, or ordered it anyways and will be installing it when it comes in.. but i digress...
so anyways, socket where the chips on the board went, too. makes life a lot easier. you need 12 hole sip socket strips, and use your iron on hole #11 to push the pin/socket out. that way you have a proper key and it will fit the circuit board.
i found to desolder, use a strong sucker. a little fresh solder on the tip of the iron, heat the joint, suck the solder out, and use some needlenose to wiggle the pin around and it should come free fairly easily. do this 11 more times per chip.
took me 4 hours and myriad bingers to accomplish. but i'm slow.
anyways, so ya got your chips out, ya got the edges scraped clear, ya chipped off some of the crud on the bump side of the chip... the non-bump side is safer, but ya really wanna get some solvent in there..
next, soak that shit. throw 'em all in your jar of acetone together, and seal the lid of the jar.
let 'em soak over nite. the reccomended time is 12-48 hours. i was figuring on 72 hours if needed.
when i checked them the next day, you could see where it was coming loose and beginning to bubble off.
me, being the impatient sort, hearkened back to my days of making parts for WMD's for the goobermint and thought, "man, i wish i had a tumbler"....
a tumbler is like a washing machine full of ceramic stones, and water with a bit of solvent in it. ya throw parts in, and it deburrs them, and polishes them to a nice uniform satin finish in industrial situations.
so i decided to just use the chips for the stones, and began aggravating the jar...errr... agitating the jar.
kindq like you'd swirl your fav beverage "on the rocks" while mindlessly doing other stuff, watching the other idiot box, blatherskiting with friends on the phone or whatever.
anyways, by about 24 hours, due to the aggravation of the agitation, the epoxy crud was really beginning to come off the backsides of all the chips, so i did a test one and found i could literally just pull the crud off with my fingers in one piece.
then i used a dental tool, some tiny files i bummed off my dentist that she uses for doing root canals, and started making sure i got as much of the goop out from between the pins of the ic's as possible. you may need to re-dunk the chips to get it all to loosen up, as the acetone evaporates, it starts to get hard again.
small sharp screwdrivers and single edge razorblades pretty much ruled. if ya use the razor, you can, if careful, juuuuuuuustslice between the legs of the 2 chips, and then drag out the goop between the legs and under them. lotta work... but in the end, good.
also make sure ya get off all the goop between the legs that plug/solder into the pcb inside the synth. once you do, install the chips into the sockets you installed, and be rewarded with a once again functioning juno or gr700 synth. you will have to recalibrate, but that info is on wayne's site, too in the service manual.
dissasembly isn't as bad as it sounds... couple nylon multiconnectors and screws, and the whole board comes right out. well designed and easy to work on.
anyways, thats my experience with doing this. it worked, it was positive, and for what it is, the 700 is kinda cool
if ya wanna play berlin's "take my breath away" in particular. it just SOUNDS LIKE the 1980's.
the gr300, being a poly analog, is much much cooler.
there's a reccomended mod to make the guitar's hex fuzz stronger, where you change two resistors from stock values of 56k and 2.2k to 100k and 5.1k.
but i don't like it... you do bump up the output of the synth by 12db, but the filter gets harsher and gnarlier sounding and loses the sweetness and ability to really dial in as many sounds in my opinion from the guitar.
i have owned a lot of analogs over the years <2600, mini and micro moog,prophet 5, juno 6, 60, 106, eml 101 etc etc> and this mod, to me, as a synthesist, is a great mod for a guitarist, but too much for my taste.
i would recommend instead splitting wayne's values to 68k and 3.3/3.6/3.9k instead. that will give about half the boost, and may make the filter response a bit sweeter while still driving it harder and about doubling the output.
but anyways... i hope some poor bastidge who gets one of these someday finds some of this info useful.
rock on, always
Thank you for this! I have a much loved Juno 106 that I found in a pawn shop in the mid-90s. I also have a Juno 60 that I picked up a couple years later. They both worked the last time I fired them up, but I've been meaning to chip away the goop on the 106 (I don't know that the 60 has the same stuff) before playing it again. This helps a lot in my research of what needs to be done.
I should probably change out the memory backup batteries and filter caps again while I'm in there...
I just have to say that you are completely insane doing that - and I mean that in a good way. It seems to me that you are never afraid to try something a little crazy to see if you can make it work - and usually it seems that you can. Well done.
I have a dysfunctional Juno-106 sitting in the basement, that I also picked up cheap. I've never been able to determine whether the 6 gooped modules all work right, because the thing doesn't boot. There might be an analog tone-generation issue, but for now the digital side is holding up the show.
Quote from: Mark Hammer on June 19, 2019, 07:18:13 AM
I have a dysfunctional Juno-106 sitting in the basement, that I also picked up cheap. I've never been able to determine whether the 6 gooped modules all work right, because the thing doesn't boot. There might be an analog tone-generation issue, but for now the digital side is holding up the show.
in my limited experience working on junos many years ago for my old keyboardist mike zappulla, i found that rebuilding the power supply brought his back from the shades when it wouldn't boot.
9 times out of ten, its just a filter cap that shorts or goes open, then the whole thing just is dead.
mark, bro, with some of the amazing shit you've done, you can most definitely handle the task!!
the worst part is the desoldering.
i take no credit for the repair, the idea behind it, or anything... i just figured out agitation would speed the process.
and going around as much of the circumference makes it way way faster for impatient guys like
oooh, shiney!
but i can confirm, it works, and well. i ordered the updated firmware to bring the 700 from 1.2 to 5.1 revision... more and better voices and tracking, and support for midi in should i dare to cobble it together and install it.
all this for a synth i'll likely sell down the road. i must be mad. ;)
but i figure, if its 100% working and guaranteed, i can sleep better at nite.... errr... all day.
my 9 to 5 is pm to am lol
Thanks for the vote of confidence, Jimi. The obligation is to finish the damn Hyperflange first, before I am allowed to move on to any other major repairs. Then there is the not-so-small matter of the Heathkit TA-17 sitting on the shelf, and..... :icon_rolleyes: :-X
hahah you got this.
if *i* as a complete newb could resurrect the ludwing phase II, i know you can do this ;)
i feel ya on projects tho.. i gotta maestro rhythm n sound g1 been sitting on my bench 5 years now waiting for me to get back to it. ;)
Where did you get your spares, Jimi?
The only ones I know about are the Analog Renaissance ones, which are definitely good, but very expensive (€46+P&P):
http://www.analoguerenaissance.com/AR80017A/ (http://www.analoguerenaissance.com/AR80017A/)
Still, with the price of Junos being what it is, they're probably worth it nowadays.
https://www.ebay.com/itm/Roland-80017a-VCF-VCA-IC-Juno106-106S-HS60-MKS7-MKS30-GR700-Referbs-Tested/302664734757?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
104$ american shipped for 2, refurbed. i had to do a little work on one still, but it was worth it.
now i got two spares, too.
tom,
you can also find a set of 6 brand new workalikes for 150 shipped out there too... i forget if it was ebay or reverb, but the price blows away the analog rennaisance price.
i mean, realistically, i'm more into paying 30 a piece than a hundred for sure!!! lol
Quotei hope some poor bastidge who gets one of these someday finds some of this info useful.
Stuff like that is what makes the internet awesome.
Quote from: Mark Hammer on June 19, 2019, 07:18:13 AM
I have a dysfunctional Juno-106 sitting in the basement, that I also picked up cheap.
Jimi, you/we simply have to get that Juno going!
thats mark's juno, jimmy
sadly, all mine have been gone for years... the last juno 106 left close to 20 years ago now. i had a juno 6, 60 and 106. the 6 was my favorite actually. really easy to program and sounded amazing.
the 60 had the 80017a disease. we had to leave it plugged in and running 24-7 and often had to reload it before gigs. i think. god.
avatar was soooooo long ago now. hard to remember!!
Ah - not good to post too early in the morning - then Mark has the challenge!
I have a Juno-6 and yes, it's an easy going monster. I was just using it to test & run-in a PA woofer replacement - Oh! that sub-oscillator and the Hold button 8)
QuoteI have a Juno-6 and yes, it's an easy going monster. I was just using it to test & run-in a PA woofer replacement - Oh! that sub-oscillator and the Hold button
I remember getting a sound close to the intro of Joan Armatrading's "I'm Lucky" from a Juno. I'm sure it's not what was used on the album but I got my jollies out of playing it just the same ;D.
I love the simplicity and utilitarian nature of the Juno line. I wish the 106 had the arpeggio function that the 60 does, but they are both perfect for me as a guitar player who needs synth sounds to fill out demos. I've played with much more complicated synths and realized that I'm too dumb to use them...
Listening to the first Rentals album made me realize how versatile they are.
and off topic for Jimi...I found a Ludwig Phase II for a surprisingly reasonable price. It was always my holy grail of pedals and really the last one I built. It needs some love to sound as good as the clone we (mostly you) worked so hard on...and I'm terrified to open it after reading your experiences with wires constantly breaking.
Quote from: Ry on June 20, 2019, 11:32:29 PM
I love the simplicity and utilitarian nature of the Juno line. I wish the 106 had the arpeggio function that the 60 does, but they are both perfect for me as a guitar player who needs synth sounds to fill out demos. I've played with much more complicated synths and realized that I'm too dumb to use them...
Listening to the first Rentals album made me realize how versatile they are.
+1 agree. Roland had a knack for designing simple stuff (which is arguably harder than designing complicated stuff). The SH101 is also a very simple synth, but it does 90% of what you might want, and it does it really well and very easily. The control ranges are set up so that it's virtually impossible to get a bad sound out of it. Great synths, despite all their limitations - and that's not easy to pull off.
Quote from: ElectricDruid on June 21, 2019, 05:51:36 AM+1 agree. Roland had a knack for designing simple stuff (which is arguably harder than designing complicated stuff). The SH101 is also a very simple synth, but it does 90% of what you might want, and it does it really well and very easily. The control ranges are set up so that it's virtually impossible to get a bad sound out of it. Great synths, despite all their limitations - and that's not easy to pull off.
I agree. Good example with the SH101.
It's quite mindblowing to compare how good it sound (like the Junos, it never sounds bad, it is an inifinte sweet spot), compared to the "not-so-appealing" featureset.
the sh101 was cool, the first "strap on".... but it was a mono synth if i recall correctly. i sold mine about about 5 years ago finally. lotta fun. but it was more of a mono analog as i recall, the juno was way better ;)
Quote from: Ry on June 20, 2019, 11:35:32 PM
and off topic for Jimi...I found a Ludwig Phase II for a surprisingly reasonable price. It was always my holy grail of pedals and really the last one I built. It needs some love to sound as good as the clone we (mostly you) worked so hard on...and I'm terrified to open it after reading your experiences with wires constantly breaking.
no terror necessary, YOU can DO THIS! if I could do it, hell, anybody could!!!
if ya need help, its here.. the wires didn't break as much as just come loose. they're best soldered to the board imho. the spade connectors they used wiggle loose with time.
i'd start with replacing all the electros. odds are that will fix most of it.
i am stoked for ya!! really cool pedal!
Quote from: pinkjimiphoton on June 21, 2019, 01:45:41 PM
the sh101 was cool, the first "strap on".... but it was a mono synth if i recall correctly. i sold mine about about 5 years ago finally. lotta fun. but it was more of a mono analog as i recall, the juno was way better ;)
"apples and oranges", as we say... Yes, the SH101 is mono, so when it comes to playing chords, well, errh, you have to get the Juno :P
But for "alive" basslines, the SH101 is very good, it has a more "vibey" feel than the Junos which have a rather "straight" sound. The SH101 is more acid, the Juno are deep and solid.
From a technical point of view, afaik, the 101 is a "synth on a chip" kind of synth, using CEM also featured in other synths from other brands. The Juno use the proprietary IR3109 chip, which sounds awesome.
yeah, to me, the two big ones were moog and arp... their filters were astounding.
but man, tell ya what... rolands could get REAL close to either... magical!! i couldn't believe the sounds i got outta that thing last nite. it was insane!! ;)
now i'm bumming cuz i really need to refurb the gr300 before taking it out... needs all the electros replaced of course. but that causes downtime, and i never wanna play a normal guitar again after last nite, lol
that said, the v 1.5 firmware for my gr700 is on the mail truck now, as soon as its delivered, i'm gonna install it. also gotta see if the two damaged chips my bassist roger repaired work! ;)
The SH101 does use a CEM3340 as its oscillator, but the filter is still Roland's IR3109 filter chip. It's a quad OTA on a chip, basically - I can't remember if the exponential convertor is on the chip or external off the top of my head.
The SH101 has a little clipping diode network in the resonance feedback loop which I think might account for its acid sound (totally agree Jimi - it has the most liquid squelch of any filter I know). It adds distortion to the feedback, but that feedback is then filtered so it never sounds crunchy, and that clipping provides limiting which allows the synth to howl without going totally crazy.
thanks tom, now i wanna add diodes to the thing :icon_twisted:
as it turned out, i bought the firmware upgrade chip kit off the bay for 30 bux. brought it from v 1.2... fairly early ... to 1.5, the final version.
man. BIG difference. tracks better, faster on the low notes.. actually sustains notes and chords n stuff now, much better aminal.
that said, the replacement chips i ordered are no good.
the ORIGINAL chips, however, work GREAT after being de-gooped and repaired between my bassist roger and i... he did the delicate SMD stuff for me at work, replaced a missing cap and ran a jumper where i'd messed a trace up on one chip, and re-soldered the pins of one of the chips, i had lifted the middle two off their pads trying to get the goop out from under the pin leads. if that shit is anywhere that's conductive, its a bad thing.
i even fixed one of the chips myself, i grafted in a missing smd cap ... well, mostly obliterated cap, i really was overzealous trying to get the goo off til i figured out i had @#$%ed up ;)
680p cap soldered in, back in business. sounds freeking phenomenal.
the chips i got on ebay tho, they have issues, or maybe they're just not compatible with my particular machine (?)
both chips would jump around in pitch during decay. even switching them to different sockets made no difference, it stayed with the chips. one wasn't as bad as the other... about 3 seconds into the decay it would start to warble, then jump up an octave... the other about 2 seconds in would first glitch up an octave, then just jump all over to random notes. not useable, unfortunately.
he said he tested them and burned them in, and i believe him. but maybe they were a better "fit" in his synth, or maybe he just plugged 'em in to see if they worked and didn't really try any long notes. short and fast stuff, no problem. but i'm a sucker for big long chords with huuuuuuuuge - ass filter sweeps.
the chip that was most unstable also manifested noise on just whatever string socket i tried it with, when the synth was turned off completely from the guitar, just that one string you'd hear crackly noise/distortion coming thru the guitar signal. even with the volume of the guitar off.
of course, at one point a pin got stuck and broke off, so i had to replace it which probably means i'm stuck with them, or at least that one <in which case i'll ask roger to de-solder, de-goop and re-solder with fresh caps and see if i can salvage it.
i got a great deal, 45 a piece, but its not a great deal if they don't work right. contacted the vendor about a return. had already left them great feedback.
of course, crickets so far ;)
ya GOTTA get the goop out from under the chip pins. or at least slice with a single edge razor so they can't have any continuity at all. makes a huge difference. all 6 chips i started with are working perfectly now, so the next step is to re-calibrate now that all the chips are in their sockets... after all the jacks are in their boxes? ;)
also, found a trick for ground loop issues with the gr300 after dicking around with it extensively most of the day... if you try and run your guitar and synth separately in two audio chains, there's two problems... the big one is a ground loop, made my normally almost silent pedalboard sound like a blown transformer buzzing.
so forget the "guitar only " out on the synth... but just for a minute.
the fix i found was to run the guitar out jack from the synth controller itself <the guitar> to my guitar rig, and the output of the "mixed" signal to the keyboard rig.
hum problem solved... but now the volume control on the guitar doesn't work right for the guitar signal. you can't kill the hex fuzz completely, and if you want nothing from the synth, well, too bad, there, buster, cuz even with it rolled all the way to guitar, and the synth off, the guitar sound keeps coming thru the keyboard rig. and the hum is still there, tho less, at least.
so i figured, this is a roland product, i betcha a doob to a donut that if i plug a cord into the guitar only output of the main synth, the gr300 itself, that maybe it would "think" the signals were separated.
bingo. now the guitar volume works for the guitar and synth as a master, as it should. and to bring up the synth, you just roll the mix knob from guitar to synth. put the switch on synth only, and you're in business, way less hum, way less noise, and you can turn up or down or mix the ratio of guitar to synth from the guitar itself.
so in the end, i just plugged in a spare right angle 1/4" plug into the guitar only output of the synth, plugged the 1/4" output of the guitar into my normal pedalboard, and the 24 pin synth cable into the synth.
a little weird with all the extra cabling, but it sounds great and now it seems to work more intuitively.
one caveat to anyone who dare try this ... the gr300 is a monster. for some reason, roland didn't put a volume control on this thing, and they probably should have. so do yerself a favor and use a volume pedal. way easier that trying to mix from the guitar, the synth volume just overpowers the guitar volume, even with the gain mod from wayne's site.
anyways... onwards n upwards n stuff....