Vintage Synth Repair

Hello.  I just purchased a CZ-1 only to discover that it has a very annoying problem.  I was 
only able to try it out with headphones - which emitted a loud, intermittent crackling sound 
that diminished in frequency (fewer occurrences of the crackling and steadier output) the 
longer the synth was on. The crackle is accompanied by near loss in volume of both crackle 
and the intended output signal.  I thought at the time that there was something wrong with 
the headphone output or jack, but when I got home, I discovered that the exact same thing 
happens via the line out jack.  After playing around with the unit, I noticed that hitting the 
keys hard often triggers a very loud instance of the crackle followed by a period of non-
crackly, full-volumed output.  Has anyone else had this issue?  I can imagine (and I know 
very very little about electronics) that the sound I am hearing is more like that of a dying 
capacitor or faulty resistor than of a bad jack (I put some Deoxit DL-100 in the jacks to no 
avail).  If anyone can point  me in the right direction of some components to test and possibly 
a schematic to accompany, I would be very thankful.

Thanks in advance!

Hi
 
I have just repaired a Yamaha Clavinova with exactly this fault and the
problem proved to be a broken solder joint on the PCB.  Anytime you have a
fault that can be triggered by thumping the instrument I would always
suspect a faulty solder joint.  Such a problem can be difficult to see.  It
can be narrowed down by gently tapping components with the back of a
screwdriver, not the metal bit, the plastic handle bit.  Alternatively
gently pressing on a component so as to flex the PCB.  All of this while the
unit is powered up.
 
Regards
Brian G3OYU
www.g3oyu.co.uk
 
  _____  

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of scituate_mass
Sent: Tuesday, 10 June 2008 05:32
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Casio CZ-1 output problem
 
Hello. I just purchased a CZ-1 only to discover that it has a very annoying
problem. I was 
only able to try it out with headphones - which emitted a loud, intermittent
crackling sound 
that diminished in frequency (fewer occurrences of the crackling and
steadier output) the 
longer the synth was on. The crackle is accompanied by near loss in volume
of both crackle 
and the intended output signal. I thought at the time that there was
something wrong with 
the headphone output or jack, but when I got home, I discovered that the
exact same thing 
happens via the line out jack. After playing around with the unit, I noticed
that hitting the 
keys hard often triggers a very loud instance of the crackle followed by a
period of non-
crackly, full-volumed output. Has anyone else had this issue? I can imagine
(and I know 
very very little about electronics) that the sound I am hearing is more like
that of a dying 
capacitor or faulty resistor than of a bad jack (I put some Deoxit DL-100 in
the jacks to no 
avail). If anyone can point me in the right direction of some components to
test and possibly 
a schematic to accompany, I would be very thankful.

Thanks in advance!
 



E-mail message checked by Spyware Doctor (5.5.0.178)
Database version: 5.09990
http://www.pctools.com/Spyware-Doctor/

Replace the relay at the output pcb.

regards,




> Hello. I just purchased a CZ-1 only to discover that it has a very
annoying
> problem. I was 
> only able to try it out with headphones - which emitted a loud,
intermittent
> crackling sound 
> that diminished in frequency (fewer occurrences of the crackling and
> steadier output) the 
> longer the synth was on. The crackle is accompanied by near loss in
volume
> of both crackle 
> and the intended output signal. I thought at the time that there was
> something wrong with 
> the headphone output or jack, but when I got home, I discovered that the
> exact same thing 
> happens via the line out jack. After playing around with the unit, I
noticed
> that hitting the 
> keys hard often triggers a very loud instance of the crackle
followed by a
> period of non-
> crackly, full-volumed output. Has anyone else had this issue? I can
imagine
> (and I know 
> very very little about electronics) that the sound I am hearing is
more like
> that of a dying 
> capacitor or faulty resistor than of a bad jack (I put some Deoxit
DL-100 in
> the jacks to no 
> avail). If anyone can point me in the right direction of some
components to

> test and possibly 
> a schematic to accompany, I would be very thankful.
> 
> Thanks in advance!
>  
> 
> 
> 
> E-mail message checked by Spyware Doctor (5.5.0.178)
> Database version: 5.09990
> http://www.pctools.com/Spyware-Doctor/
>

Hi - thanks so much for the tip.  I actually did this and it worked. I used an Omron G5V-
2-DC5 as the original part was not available.  It turned out to fit (depite the manufacturer 
telling me that it would require modification or the like).


--- In vintagesynthrepair@yahoogroups.com, "oxygeno1313" <oxygeno1313@...> wrote:

>
> Replace the relay at the output pcb.
> 
> regards,
> 
> 
> 
> 
> > Hello. I just purchased a CZ-1 only to discover that it has a very
> annoying
> > problem. I was 
> > only able to try it out with headphones - which emitted a loud,
> intermittent
> > crackling sound 
> > that diminished in frequency (fewer occurrences of the crackling and
> > steadier output) the 
> > longer the synth was on. The crackle is accompanied by near loss in
> volume
> > of both crackle 
> > and the intended output signal. I thought at the time that there was
> > something wrong with 
> > the headphone output or jack, but when I got home, I discovered that the
> > exact same thing 
> > happens via the line out jack. After playing around with the unit, I
> noticed
> > that hitting the 
> > keys hard often triggers a very loud instance of the crackle
> followed by a
> > period of non-
> > crackly, full-volumed output. Has anyone else had this issue? I can
> imagine
> > (and I know 
> > very very little about electronics) that the sound I am hearing is
> more like
> > that of a dying 
> > capacitor or faulty resistor than of a bad jack (I put some Deoxit
> DL-100 in
> > the jacks to no 
> > avail). If anyone can point me in the right direction of some
> components to
> > test and possibly 
> > a schematic to accompany, I would be very thankful.
> > 
> > Thanks in advance!
> >  
> > 
> > 
> > 
> > E-mail message checked by Spyware Doctor (5.5.0.178)
> > Database version: 5.09990
> > http://www.pctools.com/Spyware-Doctor/
> >
>

There arent a lot of pots and sliders on the unit but , after after reading about your symtoms, I would say that there's either a crack in the PC board related to the sound output area in question and/ or a soldered area with "aged" solder that's not making good connections. With the change in on-time I would say most likely the latter.

Scott  Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT 

"Resistance is futile but.....
Impedance is much more complex"