Wow, thanks for your help everybody. I guess that i am overly confident with my soldering. It looks like I'm going to get a can of deflux and follow everybody's suggestions. I do have a professional desoldering iron. I kept it at 675 degrees farenheit and the iron at 650 when removing the old chips and installing the sockets. I'm going to clean the boards and check with a magnifying glass. I'll be sure to keep everybody posted. Thanks again. One last question: What is the point of decoupling the -8.5 rail to the +6.5 rail? Wouldn't it make more sense to go from ground to -8.5 and ground to +6.5? Everybody keeps telling me I should buy the sockets with the cap in them, I don't understand how this makes sense electrically. Thanks again everybody. --- In yamahacs80@yahoogroups.com, David Rogoff <david@...> wrote: > > Mike, > > I agree with Kent. As I told you, when I re-chiped my CS80 I had a few > problems that were all tiny solder bridges between pads. I'd spend a > bunch of time with a lighted magnifier to start. Do you know which > board it is? I had strongly suggested to you that you only re-chip one > board at a time to help isolate any possible re-work goofs. > > Good luck, > > David > > kent_spong wrote: > > If I could make a suggestion to you here. > > > > Forget about the IC's being too fast or slightly different to the > > originals. I think your barking up the wrong tree here. > > > > This sounds to me like a physical problem created by replacing the > > IC's, and not the IC's themselves. > > > > When I KSR an 80 I use off the shelve new IC's, the make is of no > > concern at all. > > > > If you have used dil sockets for the IC's, check for bent legs, pins > > soldered together and even orientation. After doing over 60 CS80 > > restorations now I can still screw it up from time to time so don't > > be offended if I sound like I'm putting your work down. > > > > > > If you like, send me a detailed list of all the problems your having > > and I will work through them with you to fix your beautiful synth (I > > do love CS80's so much). > > > > > > > > --- In yamahacs80@yahoogroups.com, "mborish_2000" <mborish_2000@> > > wrote: > > > > > > It might. Some of the older chips took forever to switch. I > > haven't > > > seen a datasheet for the original 4000 series Toshiba IC's. I'm > > going > > > to do that next. The new 4000 series chips have much lower > > internal > > > resistances. > > > > > > --- In yamahacs80@yahoogroups.com, "Quazimodo" <noddyspuncture@> > > wrote: > > > > > > > > Mike I just Googled and read up on it (a bit..) > > > > > > > > Should you really worry... it looks like it would be in the > > > > *nanosecond* region anyway.... or am I wrong..? > > > > > > > > Cheers, > > > > TOM > > > > > > > > > > >
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Re: Replacing all CMOS 4000 Series Logic IC's
2009-01-20 by mborish_2000
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