Members ElectricPuppy Posted May 18, 2009 Members Share Posted May 18, 2009 I've mentioned before that I recently replaced a few of the infamous chips in my 106 from a donor and shortly thereafter another voice decided to act up. Today I decided to try that trick about removing the coating on the chip to see if that revives it. I removed the problem chip this evening and presently it's soaking in a bath of acetone. I'll post updates and pics here and let you know if it's really a viable solution! Link to comment Share on other sites More sharing options...
Members urbanscallywag Posted May 18, 2009 Members Share Posted May 18, 2009 Isn't Kerry Bradley doing some work in this area? I used to try and hack around with the 80017a and discovered it wasn't my gig. Link to comment Share on other sites More sharing options...
Members flat earth Posted May 18, 2009 Members Share Posted May 18, 2009 I'd be interested to see if it works. Seen quite a few 'faulty' 106s advertised lately. Wouldn't mind getting a cheap fixer/upper to have a go with. Link to comment Share on other sites More sharing options...
Members xpander Posted May 18, 2009 Members Share Posted May 18, 2009 a couple places make new voice chips for the 106 if it doesnt work out. Link to comment Share on other sites More sharing options...
Members gilwe Posted May 18, 2009 Members Share Posted May 18, 2009 I have about 4 or 5 faulty ones, but never had the time to get them "fixed" Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 18, 2009 Author Members Share Posted May 18, 2009 So far so good, but slowly. The coating had softened enough by this morning that I was able to scrape off the edges to let the acetone get underneath. I'll see what it looks like when I get home! Link to comment Share on other sites More sharing options...
Members gilwe Posted May 18, 2009 Members Share Posted May 18, 2009 :freak: Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 18, 2009 Author Members Share Posted May 18, 2009 :freak: Yeah... it is kind of squicky. But, the chip's already going bad, so it's not like I can make it worse, right? Link to comment Share on other sites More sharing options...
Members flat earth Posted May 18, 2009 Members Share Posted May 18, 2009 Is it the coating itself that causes the problem? Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 18, 2009 Author Members Share Posted May 18, 2009 That's what's been thought. This isn't my idea, someone else had posted this a few months back. I couldn't find the thread, though. Hey, if it works, then WOOT, 'cause while warming up the Juno to find the bad voice, ANOTHER voice started freaking out with resonance. Ugh. I think my Juno just wants to go quietly into the night. (or not-so-quietly, really.) Link to comment Share on other sites More sharing options...
Members tspit74 Posted May 18, 2009 Members Share Posted May 18, 2009 How much do new chips cost? I know a guy who has a 106 that he hasn't used in 20 years. I've always wanted to buy it from him but knowing that they're all dying doesn't exactly put a flame under my butt to wheel and deal. It's there when/if I want it, I suppose. Also, who's the source for new chips? One of the holes in my arsenal is a true analogue polysynth. The 106 would kind of fill that hole. A dual oscillator per voice poly would be ideal. But at this point, they're double the problems and double the expense. No way I'd pay a couple grand for a vintage Prophet, Oberheim, or Jupiter with their voice cards and chips dying. Especially when I just get off on making ELO sounds. Link to comment Share on other sites More sharing options...
Members poumtschak Posted May 18, 2009 Members Share Posted May 18, 2009 Just Googled for you : [YOUTUBE][/YOUTUBE] Make sure you have the right coffee can though. Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 18, 2009 Author Members Share Posted May 18, 2009 How much do new chips cost? I think a full set of 6 chips is somewhere around $300. Thanks, Poumtschak, that's exactly the video I meant! Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 18, 2009 Author Members Share Posted May 18, 2009 Also finally got to play an OASYS ... Do please give us your thoughts, feelings, etc. in an appropriate thread, O Touring One. Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 19, 2009 Author Members Share Posted May 19, 2009 I stupidly forgot to scrape off the top edge; I only did the sides this morning. D'oh! It feels softer, but it's not coming off yet, so some more soaking overnight is needed. Patience, grasshopper. Patience. Link to comment Share on other sites More sharing options...
Members AluminumNeck Posted May 19, 2009 Members Share Posted May 19, 2009 Thermally overloaded. Put heat sinks and thermal transfer materials and some active cooling on the chips. They make clip on heatsinks. If removing the resin coating is helping the chips are overheating. Does anybody have schematics for these chips ? Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 19, 2009 Author Members Share Posted May 19, 2009 They were proprietary "chips" made up by Roland, and they never published detailed schematics for them. The service manual gives an overview of the design, so some enterprising individuals have managed to make clones, some closer in operation to the original than others. I'm curious to see what's under the covers, too. We'll soon see. Link to comment Share on other sites More sharing options...
Members urbanscallywag Posted May 19, 2009 Members Share Posted May 19, 2009 I think someone, possibly Kerry, was claiming that the resin had metal particles in it which were exposed over time and shorted the PCB. Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 19, 2009 Author Members Share Posted May 19, 2009 I hadn't heard about "metal particles" in the resin, but I had heard the "becoming conductive" angle. Someone suggested moisture as a culprit. Don't know if that's true or not. I'd also heard a theory about metal migration underneath. If that's true, then simply removing the resin won't help. While I was waiting for the Juno to warm up so I could pinpoint the problem child, I copped a feel on the chips. They run warm, but not hot. Not sure how hot they will get if I just let it run. Link to comment Share on other sites More sharing options...
Members urbanscallywag Posted May 19, 2009 Members Share Posted May 19, 2009 I don't think its heat myself... Moisture...just stick 'em in the oven. Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted May 19, 2009 Author Members Share Posted May 19, 2009 Yeah I'm not buying heat, either. If it is accumulation of moisture, would just tossing them in the oven work for long? Perhaps the resin becomes more susceptable to moisture as they age and drying them out would be a short-term fix. Maybe ought to try just putting the whole board int he oven for a while. I wonder what a maximum safe temperature would be...? Link to comment Share on other sites More sharing options...
Members Bernard Posted May 19, 2009 Members Share Posted May 19, 2009 As far as I know they use epoxy potting compounds for this kind of thing. Epoxy unlike catalised resins needs to be mixed accurately. IE if you add too much hardener it does not get harder quicker, you just end up with solid expoxy filled with unreacted excess hardener. The unreacted resin of these two part epoxy systems is corrosive, so if a manufacturer does rush and mess up the mix then it could cause problems. Cleaning off completely using accetone and scrubbing with a tooth brush would get rid of any conductive problem as the chap in the vid suggests. One other effect with electronics is all the banging and handling done in such activity, it can also restore life to a circuit, albeit for a short time. Some car mechanics will give an electronic igintion module a sharp tap to get the thyristor to fire up and start a car in emergency. Hopefully the problem is corrosion as that accetone bath will be a longer term fix. Good luck Link to comment Share on other sites More sharing options...
Members Bernard Posted May 19, 2009 Members Share Posted May 19, 2009 I have never had to soften epoxy, although I see some mention of acetone being used on the web. It may be that the potting compound was something else as it softened so well in acetone in that vid. Link to comment Share on other sites More sharing options...
Members kpatz Posted May 19, 2009 Members Share Posted May 19, 2009 Wow, wish I knew about this trick a couple winters ago when I was refurbing a couple 106es. It probably won't salvage every chip but even if it brings back 50% of them it's a nice cheap solution. And once the resin is off, one could touch up the solder joints to fix a failed chip as well. Link to comment Share on other sites More sharing options...
Members gilwe Posted May 19, 2009 Members Share Posted May 19, 2009 I'd put the 250$ for a set of clones and make a reliable 106 I can use for decades more (hopefully) Think about it - I can play mine live without being worried about faulty ICs Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.