[sdiy] CZ-1000 update and memory mod help

Ullrich Peter Peter.Ullrich at kapsch.net
Wed Mar 11 17:23:24 CET 2020

Yes, this curcuit is really crazy... The circuit looks more like a Japanese letter than a power supply circuit...

I measured my CZ-101 voltages and it doesn't fulfill the requirements so that Maartens circuit could work ☹
My RAM voltage is always 4,24V - even if the power is switched off. When switched on it should rise up to 4,75 to 5,25V but not in my unit.
And the VBR voltage cannot be brought down to 3.2V as necessary...

So for me this circuit will not work. The already ordered DS1210S chip will be stored forever I bet...

I think I will design a cartridge for the CZ-101 that uses a ferroram, so that no battery is used.
I already have the chip at home for years but never really started this project...


http://www.ullrich.at.tt (my webpage)
https://www.instagram.com/synpro  (my Instagram account)
http://www.rc100-usb.at.tt (Roland Sampler Tool)
http://synpro.heimat.eu/datadial.htm (DataDial Synth Addon / can also be used for the Casio CZ synths!)

-----Ursprüngliche Nachricht-----
Von: Synth-diy <synth-diy-bounces at synth-diy.org> Im Auftrag von MTG
Gesendet: Mittwoch, 11. März 2020 17:00
An: synth-diy at synth-diy.org
Betreff: Re: [sdiy] CZ-1000 update and memory mod help

Wow, that (original) circuit is insane. Hopefully someone on this list can understand all of it because I sure can't.

On 3/9/2020 9:31 PM, Joe Frey wrote:
> Hello all, To those that answered my original post asking for guidance
> I found the problem. The output relay had gone bad and needed to be replaced.
> So, after getting the synth to sound good again I decided to make an
> improvement and add ram power management so my custom patches wouldn't
> disappear when I put the synth in it's case for half a year. It turns
> out there's a chap that made a mod that I found out about that people
> say works. I contacted him and though he no longer provides the kit he
> did supply the info to make that mod.
> https://www.artefacts.nl/bitsandpieces.html
> He also gave this advice, "_Before you start modifying the CZ you
> should check if you can change the standby voltage as described in the
> installation manual_. You should also check the RAM chips get a
> voltage between 4.8Volt and 5.2Volt when the unit is switched on. If
> you can not get these voltages within range the kit will not work."
> Of course being me, I ignored the first line of the instruction and
> made and installed the mod. DOH! Now, everything is cozy and in place
> but I can't use the trimmer to get the standby voltage down to 3.2V. I
> can get it to 3.7V. I am wondering if I put a diode in the end of the
> VBR regulator circuit to use the diode drop and try and  get from 3.7 to 3.2V?
> The schematic is found here.
> https://www.synthxl.com/wp-content/uploads/2018/01/Casio-CZ1000-schema
> tics.pdf
> And the VBR power supply is at page 4, grid 4F. And, the ribbon cable
> pin I am measuring voltage at is pin 9.
> Any advice is appreciated. JoeF.
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