Pardon the newbie if you feel that I somewhat offend with the following remarks but......isn't the point of this group to help others with their expertise (or lack thereof) in the repair and upkeep of these machines? Your post does not seem very helpful at all and rather mocking. My soldering skills are fine and no, I did not damage the board as I was very careful when removing the old components, nor was I worried about static as I was using the proper anti-static equipment. And yes, I am sure about the values of all those caps. I made sure of it before replacing all 100 of them that I had the correct values. I made doubly sure of it before I ordered them from an electronics supply house in the UK since they are not readily available here in the USA.
Again, mocking someone who is looking for help here who is not familiar with these particular machines is not very helpful. If you do have some real insight as to where I should continue to "find the fault" so I can fix it, that would be great. Otherwise, please keep your not very helpful comments to yourself.
--- In Simmons_Drums@yahoogroups.com, "gordonjcp" <gordon@...> wrote:
>
>
> > If the mux/demux caps are worn out and ALL the caps are the same age on the board, wouldn't it make sense to change them all? They are cheap enough.
>
> They don't wear out. They rarely fail. When they do, they cause very, very distinctive faults.
>
> It's worth noting that just about the only capacitors I have ever seen fail have been electrolytics used in cheap crappy switched-mode power supplies (which you don't have here) and disc ceramics used at high voltage or in RF amps. In synthesizers I've changed maybe a dozen genuinely faulty capacitors in 20-odd years.
>
> Capacitors don't fail, and they don't wear out.
>
> > As I stated previously, that didn't change the issue I'm having with it, so now it has to be the mux/demux ICs, as stated earlier in this thread by Michael himself on the issue with this machine that this member is having.
>
> Of course it didn't, and now you've got to do what you should have done to begin with - diagnose the fault! The 405x family multiplexers do fail, with either an output getting "stuck" usually to one supply rail or the other, or the inputs just not switching at all. Get an oscilloscope, track down the fault, and replace just the part that has failed.
>
> > If I've replaced all the caps with the proper values and it does the exact same thing it did before, how then could I have created more problems? Can you please explain that theory?
>
> How good is your soldering? Are you sure you read all those capacitors correctly? Are you sure you didn't damage the fragile through-hole plating on the boards? Are you sure you didn't zap something with static?
>
> I won't touch ∗anything∗ that's been "re-capped". I often see synths that have been "re-capped" by some Expert Synth Doctor that then never quite works right again, and then they're just too much bother to put right.
>
> Don't muck about. Track the fault down and fix ∗just that fault∗.
>
> --
> Gordonjcp MM0YEQ
>