Patches and discussion for Ensoniq VFX family

I just got my vfx-sd.it's a rom 1.37/seq 2.22(?). i keep hearing 
about this coil board problem.I haven't had any problem yet
(thankfully),but the way life is,i may have in the future.My question 
is:how do you know that the problem has been fixed,and if it becomes 
a problem,how do i go about fixing it? Does it need special parts?
                  
                 Thanks everybody(i'm still new to groups)
                      John

John
         You can check out the ERROR 144 page on my site for all information 
on the coil board problem ( http://hometown.aol.com/mishon66/errorpage.html  
) some of the links are inop (and I am working on that) but I have the last 
service bulletin #12 printed on this page, it gives all the details on the 
coil board problems.
Richard

ok, I have a vfx all the fuses blew and after
replacing them the unit stopped all audio output. all
other features seem to work including midi out to
other midi devices, but alas no sound. Any remote clue
what a guy could do next? is there a master reset
other than the preset combo? or is this unit finally
dead?

Richard

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In a message dated 11/19/01 4:21:53 PM Pacific Standard Time, 
computeroutlaw@... writes:

<< Subj:     Re: [Ensoniq-VFX-SD] board problem
 Date:  11/19/01 4:21:53 PM Pacific Standard Time

 From:  computeroutlaw@... (R. Green)
 Reply-to:  Ensoniq-VFX-SD@yahoogroups.com
 To:    Ensoniq-VFX-SD@yahoogroups.com
 
 ok, I have a vfx all the fuses blew and after
 replacing them the unit stopped all audio output. all
 other features seem to work including midi out to
 other midi devices, but alas no sound. Any remote clue
 what a guy could do next? is there a master reset
 other than the preset combo? or is this unit finally
 dead?
 
 Richard
  >>
Check all the diodes next to the fuses first.
Rich

WOW, I thought he was giving useful information. If someone dosent know how 
to test a diode they should not be messing around with them anyway, but this 
does give them enough information to find someone who does know how to test 
them (you know a good direction to start trouble shooting).


>From: midiman11 <midiman11@...>
>Reply-To: Ensoniq-VFX-SD@yahoogroups.com
>To: <Ensoniq-VFX-SD@yahoogroups.com>
>Subject: Re: [Ensoniq-VFX-SD] board problem
>Date: Tue, 20 Nov 2001 11:11:30 -0500
>
>I hope you don\ufffdt assume everyone knows how to test a diode (and even 
>testing
>\ufffdin-circuit\ufffd components)
>Give the guy some useful info along with your suggestion
>
>tim
>
>
>on 11/19/01 10:38 PM, mishon66@... at mishon66@... wrote:
>
> > In a message dated 11/19/01 4:21:53 PM Pacific Standard Time,
> > computeroutlaw@... writes:
> >
> > << Subj:     Re: [Ensoniq-VFX-SD] board problem
> > Date:  11/19/01 4:21:53 PM Pacific Standard Time
> > From:  computeroutlaw@... (R. Green)
> > Reply-to:  Ensoniq-VFX-SD@yahoogroups.com
> > To:    Ensoniq-VFX-SD@yahoogroups.com
> >
> > ok, I have a vfx all the fuses blew and after
> > replacing them the unit stopped all audio output. all
> > other features seem to work including midi out to
> > other midi devices, but alas no sound. Any remote clue
> > what a guy could do next? is there a master reset
> > other than the preset combo? or is this unit finally
> > dead?
> >
> >
> >
> > Richard
> >>>   >>
> > Check all the diodes next to the fuses first.
> > Rich
> >
>


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In a message dated 11/21/01 6:39:20 AM Pacific Standard Time, 
GROCECHRIS@... writes:

<< Subj:     Re: [Ensoniq-VFX-SD] board problem
 Date:  11/21/01 6:39:20 AM Pacific Standard Time

 From:  GROCECHRIS@... (chris groce)
 Reply-to:  Ensoniq-VFX-SD@yahoogroups.com
 To:    Ensoniq-VFX-SD@yahoogroups.com
 
 WOW, I thought he was giving useful information. If someone dosent know how 
 to test a diode they should not be messing around with them anyway, but this 
 does give them enough information to find someone who does know how to test 
 them (you know a good direction to start trouble shooting). >>

I do know how to test Dioeds and I assumed that since the person with the bad 
unit had the top open they would know what to do.
Rich

I am thankfull for ALL of your comments and help.
Diodes checked fine...power fine...board is
dead..(r.i.p)...gotta get another it would seem...how
about a suggestion there? And again thanks for all the
help!!

Richard
--- mishon66@... wrote:
> In a message dated 11/21/01 6:39:20 AM Pacific
> Standard Time, 
> GROCECHRIS@... writes:
> 
> << Subj:     Re: [Ensoniq-VFX-SD] board problem
>  Date:  11/21/01 6:39:20 AM Pacific Standard Time
>  From:  GROCECHRIS@... (chris groce)
>  Reply-to:  Ensoniq-VFX-SD@yahoogroups.com
>  To:    Ensoniq-VFX-SD@yahoogroups.com
>  
>  WOW, I thought he was giving useful information. If
> someone dosent know how 
>  to test a diode they should not be messing around
> with them anyway, but this 
>  does give them enough information to find someone
> who does know how to test 
>  them (you know a good direction to start trouble
> shooting). >>
> 
> I do know how to test Dioeds and I assumed that
> since the person with the bad 
> unit had the top open they would know what to do.
> Rich
> 


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On Wednesday 21 November 2001 04:19 pm, you wrote:
> I am thankfull for ALL of your comments and help.
> Diodes checked fine...power fine...board is
> dead..(r.i.p)...gotta get another it would seem...how
> about a suggestion there? And again thanks for all the
> help!!
>

My guess would be (since you said that it was the audio output that is dead) 
is that one or more of the transistors (Q11-Q16 on my SD1) used as amplifiers 
for the output, or somewhere around there, have died. If you know your way 
around a soldering iron, you could desolder each transistor and replace it 
with a transistor socket, check each transistor in turn, and replace/reinsert 
the transistors as you go. Putting the sockets in place will make it easier 
to fix if you blow a transistor in future.

If they all test out fine and the problem is elsewhere, then you still have a 
dead board, if you find a bad transistor or two, then you have a fixable 
board :)

Oh, and check the headphone ouput, it is seperate from the Audio output 
jacks, if there is signal there, but not on the outs, then its almost 
certainly the transistors.

Other possible causes could be dead DACs (that might be tricky, you probably 
can't easily get replacement DACs, but you never know), dead op-amps (the 
plethora of 8pin IC's around the audio outputs,  or any of the few dozen 
resistors around the op-amps.

Resistor death should be apparent if thats the cause - resistors usually die 
quite violently. IC death can sometimes be determined by smelling the ICs.

Most of the analog parts in the VFX are thankfully common place parts, so it 
shouldn't be too hard to get replacements, as I said though, the worry is if 
the DACs are dead, a lot of the DACs from that time period are no longer 
made, and have no obvious equivalent parts. (If you DO know electronics 
fairly well, it would probably be possible to knock together a quick and 
dirty 'fix' using a daughterboard (that would have a DIP format connector and 
replace the DAC(s) pin for pin) with a PIC + modern DAC - heck, you could 
even improve the audio quality perhaps :) The only problem with this, might 
be finding the specs on the original DACs if they are (long) discontinued...

In a message dated 11/21/01 1:44:34 PM Pacific Standard Time, 
suzanne@... writes:

<< 
 On Wednesday 21 November 2001 04:19 pm, you wrote:
 > I am thankfull for ALL of your comments and help.
 > Diodes checked fine...power fine...board is
 > dead..(r.i.p)...gotta get another it would seem...how
 > about a suggestion there? And again thanks for all the
 > help!!
 >
 
 My guess would be (since you said that it was the audio output that is dead) 
 is that one or more of the transistors (Q11-Q16 on my SD1) used as 
amplifiers 
 for the output, or somewhere around there, have died. If you know your way 
 around a soldering iron, you could desolder each transistor and replace it 
 with a transistor socket, check each transistor in turn, and 
replace/reinsert 
 the transistors as you go. Putting the sockets in place will make it easier 
 to fix if you blow a transistor in future.
 
 If they all test out fine and the problem is elsewhere, then you still have 
a 
 dead board, if you find a bad transistor or two, then you have a fixable 
 board :)
 
 Oh, and check the headphone ouput, it is seperate from the Audio output 
 jacks, if there is signal there, but not on the outs, then its almost 
 certainly the transistors.
 
 Other possible causes could be dead DACs (that might be tricky, you probably 
 can't easily get replacement DACs, but you never know), dead op-amps (the 
 plethora of 8pin IC's around the audio outputs,  or any of the few dozen 
 resistors around the op-amps.
 
 Resistor death should be apparent if thats the cause - resistors usually die 
 quite violently. IC death can sometimes be determined by smelling the ICs.
 
 Most of the analog parts in the VFX are thankfully common place parts, so it 
 shouldn't be too hard to get replacements, as I said though, the worry is if 
 the DACs are dead, a lot of the DACs from that time period are no longer 
 made, and have no obvious equivalent parts. (If you DO know electronics 
 fairly well, it would probably be possible to knock together a quick and 
 dirty 'fix' using a daughterboard (that would have a DIP format connector 
and 
 replace the DAC(s) pin for pin) with a PIC + modern DAC - heck, you could 
 even improve the audio quality perhaps :) The only problem with this, might 
 be finding the specs on the original DACs if they are (long) discontinued...
  >>
Ya what she said
Rich