more broken cz's...free
2004-08-10 by jbrave
I've got two broken cz 101's, one I bought in 1985 new, and one I bought broken off ebay... Anyone in northern California want em? What I need is a drum machine, if anyone has a spare... Joel
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----- Original Message -----
From: Scott Nordlund
To: CZsynth@yahoogroups.com
Sent: Monday, August 09, 2004 9:45 PM
Subject: RE: [CZsynth] Broken CZ5000 part 2...can anyone translate this??
>Hi everyone,
>This is my first post here. I recently picked up a second hand CZ5000.
>I have been trying to get it working. I noticed that a couple of the
>fuses on the PCB near the power supply in were missing so I have
>replaced those with the correct value and checked the other fuses.
>All the boards seem to be in pretty good shape with no sign of
>missing, broken or fried components. Also the fuse thing on the
>bottom is set to the correct voltage (240V for the UK).
>At the moment when I turn the thing on none of the led's on the
>control surface (including the mod/pitch wheel led) come on and the
>only thing that comes to life is the lcd display which faintly shows
>a row of pixel blocks where presumably the edit parameters and patch
>name should be. If anyone has any speculative ideas about what is
>wrong with the synth I would love to hear them as I am keen to try
>and fix it. Even if you think that it is beyond repair please let me
>know. If it is truly screwed then I will happily take it to pieces
>and send out any spares that anyone here might need ie:
>buttons/switches etc.
>Also what is the battery compartment for on the bottom of the
>synth..is this to save patches in the memory when it's disconnected
>from the mains?
>Thanks for reading this...I'd love to hear from you. *NK
Yes, the battery is for patch memory.
The first thing you do for a broken synth is check all of the connectors to
make sure they're not loose or corroded and reseat all of the socketed chips
(carefully), then do a hard reset. If you can manage, check the power
supply. After that it gets a bit more difficult...
>Casio CZ 5000 1985
>No function,LEDs or LCD display
>The only convenient 0V point for the TTL I could
>find was the -ve pin of the ps bridge rectifier.
>No 5V for the TTL. It looks as though the keyboard had been
>dropped as the large electrolytic on the ps had moved and
>consequently the track continuity to the 5V regulator part of
>the ps was broken under the capacitor pin,not obvious at al.
>With all 3 connectors unplugged and PA order on main pcb
>not the ps end which is different order.
>PA 0,15.3,-16,0,5.6,0,5.2,0,5.2
>PC 0,0.03,5.2
>PD 0,16,15.3,0,0
>
>I found the above on a website...it sounds almost identical to my
>problem...can anyone spell it out a bit more as to where i should be
>looking for this capacitor pin..as i am no expert in these maters.
>Any help would lift my day.thanks.....
He's saying..he tested the power supply (using the pin of the bridge
rectifier as a ground point) and found that there was no +5V supply for the
digital logic (generally power supplies generate different voltages for
different parts of the device to use- for example +5V for digital parts,
+12V, and -12V for analog). The circuit board trace under the largest
capacitor was broken. If you want, you can look on the bottom of the power
supply board to see if anything is messed up, but as you said there's a line
on the LCD, I would imagine that the digital circuits are getting power.
Anyway it's pretty unusual to have a broken trace like that..
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