Synth-DIY Yahoo! Groups Archives

Fw: Death of a Serge

2000-12-17 by J. Larry Hendry

For those of you who do not subscribe to AH or Synth DIY, I thought this was
interesting.  Just one more reasons to buy from someone willing to supply
schematics.  Now, who would that be??  Let see..... OH yes.... MOTM, and
Blacet jump right out there (and, there are others).  And, what's the deal
about this "extended life-examining pilgrimage in the Upper Midwest."
Inquiring minds want to know.

Larry H

Show quoted textHide quoted text

----- Original Message -----
From: Jim Johnson <jamos@...>
To: <analogue@...>; <synth-diy@...>
Sent: Sunday, December 17, 2000 11:18 AM
Subject: Death of a Serge

Wel, bad news...

.. late last week my Serge stopped making sound.. so yesterday I popped it
out of the case, powered it up.. only to see smoke start pouring out of a
capacitor!

Now I'm trying to decide what to do. Obviously I will test the power
supply, but I doubt that the new Power One supply I put in is bad. Seems
more likely that the cap itself failed, and is shorting the supply.. though
there may be more wrong.

I realize that schematics of this are closely held secrets, that repair can
only be done by one man, and that he is currently on some extended
life-examining pilgrimage in the Upper Midwest. However, maybe somebody out
there who has puzzled through these things in the past can help me. The cap
in question is a ceramic disk on the Variable Q VCF board, about halfway
down, between a 100K trimpot and am LM3080. It's right next to the +15v
line, so I bet it is a decoupling cap. Can anyone confirm this?

TIA.. please ...
Jim Johnson
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info@...

Re: Fw: Death of a Serge

2000-12-17 by Dave Fulton

I can't tell you about Rex & his pilgramage and I know this may be hard
,you might just have to send it a really good tech. Someone who will 
take the time to reverse (not to hard it will just take a bit of shop 
time) engineer it. Rex's PCB's are far from complexed. As far as I 
know, the Oakland office is now closed. Just a # and a chance that Rex 
may get back to you. In the mean time you could just bypass that PCB on 
his "power distribution" bus (ok 4 wires that jump from board to 
board!) and you can use the rest of the panel safely. Check to see if 
that LM3080 is shorted. In fact it might be quicker to check all the 
active components. I have had NEW Serge panels with wires not soldered 
to components on the front panel and just plain blown OP amps. And I 
have seen both together! The PCB's are usually fine it's just the lash 
up to the front panels that creates the problems.

Good sounding stuff. But is it worth it?

I don't know.

Dave



--- In motm@egroups.com, "J. Larry Hendry" <jlarryh@i...> wrote:

Show quoted textHide quoted text

> For those of you who do not subscribe to AH or Synth DIY, I thought this was
> interesting.  Just one more reasons to buy from someone willing to supply
> schematics.  Now, who would that be??  Let see..... OH yes.... MOTM, and
> Blacet jump right out there (and, there are others).  And, what's the deal
> about this "extended life-examining pilgrimage in the Upper Midwest."
> Inquiring minds want to know.
> 
> Larry H
> 
> 
> ----- Original Message -----
> From: Jim Johnson <jamos@t...>
> To: <analogue@h...>; <synth-diy@n...>
> Sent: Sunday, December 17, 2000 11:18 AM
> Subject: Death of a Serge
> 
> 
> Wel, bad news...
> 
> .. late last week my Serge stopped making sound.. so yesterday I popped it
> out of the case, powered it up.. only to see smoke start pouring out of a
> capacitor!
> 
> Now I'm trying to decide what to do. Obviously I will test the power
> supply, but I doubt that the new Power One supply I put in is bad. Seems
> more likely that the cap itself failed, and is shorting the supply.. though
> there may be more wrong.
> 
> I realize that schematics of this are closely held secrets, that repair can
> only be done by one man, and that he is currently on some extended
> life-examining pilgrimage in the Upper Midwest. However, maybe somebody out
> there who has puzzled through these things in the past can help me. The cap
> in question is a ceramic disk on the Variable Q VCF board, about halfway
> down, between a 100K trimpot and am LM3080. It's right next to the +15v
> line, so I bet it is a decoupling cap. Can anyone confirm this?
> 
> TIA.. please ...
> Jim Johnson
> Metaphoric Software
> -------------------
> Makers of Techno Toys
> Software for Electronic Music
> http://www.technotoys.com
> info@t...