Patches and discussion for Ensoniq VFX family

I speak slightly too soon . . . . there is a small problem with some of the patches still which use certain effects where we get digital coruption of sorts . . . the default "ITS-A-SYNTH" patch does it, as does "SPRIGTIDE" (badly) - both of these use the "CHORUS+REVERB1" effect, and #2 does it, but most of the others seem OK . . . has the DSP chip gone bananas?

--- In Ensoniq-VFX-SD@yahoogroups.com, "chris_i_rolland" <chris_i_rolland@...> wrote:
>
> After far too much procrastination, I finally decided to get this sorted. After cross-referencing the circuit diagrams in the files area I ordered replacements for ALL the radial caps, and the three can type axials, and got soldering. As suggested I got 105 degree heat tolerance caps where poss, and now all appears well again!
> 
> The only niggle now is the fact it can't read a cartridge on the first try, I always have to reinsert but it causes me no bother, so I'll probably procrastinate some more.
> 
> Thank you all for help and advice,
> 
> Chris.
> 
> --- In Ensoniq-VFX-SD@yahoogroups.com, "jammie" <jammie.emma@> wrote:
> >
> > no but just change the caps diodes rarely go and if they do the go with a bang
> > 
> > you would know if the diode blow as they shatter in half and can blow holes in the pcb but this is usually due to reverse voltage being higher than the diode can take
> > 
> > the glass rectifier diodes used in the psu are over sized for heat dissipation so would not fail
> > 
> > they are linear psu,s and just rely on bridge rectifers for dc
> > then smoothing caps to smooth the semi ac voltage into a pure rippless dc line which then go to power regulators for regulated dc lines
> > 
> > they are the most common type of psu but are not energy efficient
> > 
> > but the good thing is the most common problem with them is heat on the caps 85oc not so bad for most european countries as they dont get hot weather but in the states and humid countries of asia the ambient tems are high and so the working temps are higher the 85oc caps that they used
> > 
> > had a low life at 85oc extremes and so when they get hot they expand and start to lose there ability to hold charge so when they discharge there signal is week eventually they stop all ripple all together from the bridge circuit which looks 
> > 
> > like camel humps on a scope the more caps put in parallel to earth the smoother the dc lines
> > 
> > ensoniq used large caps for this
> > 
> > im an ex ensoniq authorized repair tech from the uk and have been fixing these synths for over 20+ years
> > 
> > i work on components level
> > 
> > the ensoniq synths are well designed and the psu is the most common fualt of there synths
> > 
> > all there psu designs are i dentical in there topology
> > 
> > this is so they could use the same parts for all ther designs and the psu is made from off the shelf components so are easily repaired
> > 
> > the d4+ uses rubbish computer motherboard caps with a life of only 2000 use at 85oc 
> > 
> > i have had to change 100 caps on these boards as they just fail cuasing al types of problems the biggest is dc blocking in the ac audio meaning getting 15vdc on the 3.3v audio circuits
> > 
> > now other manufacturers used switchmode psu 
> > 
> > the korg m1 t1 o1w use this type of device and they use italian transformers which you can buy anymor and they 
> > 
> > burn out i have had to make linear supplies to replace these so that i could carry on using these machine as linear 
> > 
> > is easy to do and only require a very few components
> >   ----- Original Message ----- 
> >   From: chris_i_rolland 
> >   To: Ensoniq-VFX-SD@yahoogroups.com 
> >   Sent: Wednesday, February 15, 2012 9:21 AM
> >   Subject: [Ensoniq-VFX-SD] Re: Crapulence / Audio Output / Power Supply?
> > 
> > 
> >     
> > 
> > 
> >   --- In Ensoniq-VFX-SD@yahoogroups.com, Rish <rish@> wrote:
> >   >
> >   > Try replacing all the diodes on the power supply board, it sounds like they are dying off.
> >   > 
> >   > Rish
> >   > 
> >   > Life is like MIDI, your either IN, OUT or THRU.
> >   > 
> >   > 
> >   > On Feb 14, 2012, at 1:17 PM, "chris_i_rolland" <chris_i_rolland@> wrote:
> >   > 
> >   > > So reading through a lot of the threads here I see a number of possible posts related to what I have, but am not sure exactly which is most relevant if at all.
> >   > > 
> >   > > I have had my VFX from ages past, and have updated EPROMS, changed batteries, fixed the keyboard and done all the things we have to do to keep these babies alive. However recently I have had a problem that I can't put my finger on. When I turn on the VFX all is well, however after a while (and it could be 30 minutes, or it could be a couple of days - yes I said days), a couple of things happen. Firstly on the audio output I lose almost all of the left channel, at this point I sometimes (but not always immediately) start getting what others have decscribed as "crapulence", but this is very dependant on the patch. Or actually it is dependant on the Effects in use, and it tends to be only on the release of a note . . . Rebooting the keyboard does NOT fix the issue, but leaving it unplugged for some time does (and that can also vary between leaving it for a few hours to days/weeks).
> >   > > 
> >   > > Frankly I am tempted to get another VFX should I ever see one on eBay/Gumtree (or a VFX-SD or maybe an SD-1 if they are patch compatable), but really I'd like to fix this venerable old workhorse. I have skills in soldering and electronics, but don;t have the detailed diagnostic skills to work out exactly what is going wrong, which is why I went through the threads, and see comments on Bias adjustment, or the Power Supply, but somehow I suspect there are multiple issues running in here, which is why I hope the collective pool of wisdom can assist here . . . all suggestions gratefully received.
> >   > > 
> >   > > Chris.
> >   > > 
> >   > >
> >   >
> > 
> >   Two votes for power . . . I did have the full circuit diagrams, so will trawl through the studio to look for them as I mislaid them a while ago, and replace the diodes as a start . . . can replacement Power supply boards be gotten hold of easily if it is something more than diodes/capacitors?
> >
>