Members AluminumNeck Posted September 23, 2009 Members Share Posted September 23, 2009 If so, why does it only seem to affect those chips in particular? Not disagreeing, but it seems a very "targeted" effect if that's true. Seems like it should be affecting other aspects of the synth, too. Could be a vendor issue. Maybe they used a insufficnet cleaning process. different vendors maye have supplied a whole slew of compnents. It there are other potted chips on the board maybe opening a few of those chips may shed some light on the subject. It could also be a problem specific to one plant and on manufacturing line. One line may have had a in adequately performing cleaning machine and the problem didn;t start appearing till many many years after the machine was out of production. moisture buildup in fluix takes time so no doubt that we might never see it unless the sealing agent fialed. Link to comment Share on other sites More sharing options...
Members p_wats Posted September 25, 2009 Members Share Posted September 25, 2009 Update: I finally got most of the resin off the chip this morning (aside from the back). In the process I managed to loose another chip leg, but was able to fashion two new ones out of old clippings. I re-installed the chip this afternoon and have been playing it off an on all day with great success! Link to comment Share on other sites More sharing options...
Members iphones Posted October 16, 2009 Members Share Posted October 16, 2009 Hi everyone. I want to avoid desoldering the voice chips but it seems that 2 of mine are messed up. One voice chip causes notes to sustain or hang but there is also this annoying scratchy sound - and notes that play randomly when nothing is being played. Are these problems caused by the voice chips alone? Could the scratchy sound be a loose ground or something? Is it possible to scrape away the resin without removing the chips? Here is a song I made by playing 2 chords over and over in diagnostic mode http://z1.droplink.me/downloader/5df68e3b1h613e28bcc7217a782d434g/broken--%28.m4a Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted October 16, 2009 Author Members Share Posted October 16, 2009 Are these problems caused by the voice chips alone? Could the scratchy sound be a loose ground or something? Very likely it's the VCF/VCA modules (whate everyone calls the "voice chips"). Is it possible to scrape away the resin without removing the chips? There's no simple mechanical way of removing the resin that I'm aware of; The modules will have to be removed so they can be soaked in solvent. If you're not comfortable doing this, then you should find someone who is. Link to comment Share on other sites More sharing options...
Members FilipDK Posted November 25, 2010 Members Share Posted November 25, 2010 I have difficulties in removing the resin between the IC legs. Any suggestions? I was thinking since the resin is also under the IC itself, then it might still somewhat short the IC legs, since after removing the resin between the legs it still touches the legs from behind (As far as I can se from photos). Any thoughts? Somewhere (I think on YouTube) I read that one should remove the more sticky resin on the 10 laser trimmed resistors. As far as I can see ElectricPuppy didn't do this and still got the chips to work. Any comments on that? Thanks for a lot of good info. ----------------- As far getting the 80017A voice chip off the PCB: I got the chip out pretty easily by using this? inexpensive tool: Velleman VTDESOL3U Vacuum Desoldering Pump With Heater 30W. I vacuumed each pin 2 or 3 times from the back of the PCB - only heating each pin a few seconds every time. I then used a small screwdriver to wiggle? the pins gently about to loosen them (still from the back of the PCB). After that I very, very gently wiggled the chip itself until it practically fell out. I didn't use any force anywhere in this process, since that might damage the chip. Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted November 26, 2010 Author Members Share Posted November 26, 2010 I removed the resin between the legs on the IC pins with a very fine pick and pair of tweezers. Very fine tweezers, actually. There was a lot of squinting involved. Link to comment Share on other sites More sharing options...
Members FilipDK Posted November 29, 2010 Members Share Posted November 29, 2010 I gave up on removing the resin between the legs on the IC pins after 5 days in the acetone. But I just installed the chip (80017A 40A) and the damn thing works. Incredible. Just incredible. How important is the silicone conformal coating procedure? What will happen if I don't do this? Link to comment Share on other sites More sharing options...
Members ElectricPuppy Posted November 29, 2010 Author Members Share Posted November 29, 2010 Honestly, I don't know. I did it to mine mainly as a precaution. I seem to recall reading somewhere that the exposed resistors are susceptible to moisture (i.e. humidity changes), so... Your mileage may vary. Link to comment Share on other sites More sharing options...
Members AnalogGuy Posted December 18, 2010 Members Share Posted December 18, 2010 I bought now MKS-30 + PG-200. Should I do this chip revival as soon as possible or is it wiser to wait until it starts the "acting weird"? Is it really a long term solution to remove the epoxy and replace it with silicone? Link to comment Share on other sites More sharing options...
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