[sdiy] Repair help Waldorf Chord Gekko

[Ullrich Peter]

Hi Sam!

Thank you very much for the pictures. Very interesting!

The design of the old Gekkos was very simple and quite cheap but it could be copied by everyone as the eproms could not be copy protected.

The new design with the PIC can be copy protected - so a big benefit from the manufacturer side.
And you can reprogram the chip "incircuit" - I bet that the 5 edge contacts are the incircuit programming interface.
Eproms can not be reprogrammed incircuit...

Of course it would have been possible to make a newer version out of the 8031 design by using one of the 87C51 or 89S82 single chip 
microcontrollers but maybe they also made some software improvements that were easier to program on the PIC platform.

So in your case I don't think that the PIC has lost its program, I have never heard that this happened. I think that there is another problem.
Maybe the crystal is damaged (did your Gekko fell on the floor too hard?) or there maybe a problem with the power supply.

The original Gekkos also had the problem that they didn't work with all keyboards as some keyboards have a midi output circuit that
is different to the circuit recommended in the MIDI kompendium. And so the Gekkos wasn't able to get the power and MIDI data at the same time.
The little Fatar Studio 49 master keyboards for example don't work with the Waldorf Gekkos...

Ciao
Peter

________________________________________
Von: Sam Ecoff [sam at synthasonic.com]
Gesendet: Freitag, 22. April 2011 16:16
An: Ullrich Peter; sdiy DIY
Betreff: Re: [sdiy] Repair help Waldorf Chord Gekko

Interesting. The one I have is completely different from these pics. I'll upload a few pics of mine:

http://www.samecoff.com/ChordGekko/chordgekko.html

I don't know if mine is older or newer. I didn't find out about the Gekkos until after they had discontinued them, and I wrote to Waldorf and asked if there was any possibility of getting one, and they said they had just one left which I could purchase. I noticed when it came that it appeared that it had been pried open once before with a screw driver, so I don't know if it was a refurb or some such circumstance. They didn't say and I didn't ask.

Sam E.

On Apr 22, 2011, at 4:20 AM, Ullrich Peter wrote:

> You can see pictures of the old Gekko Hardware here:
> http://pics.studiorepair.de/Waldorf/Gecko/slides/Waldorf_Gecko_PCB.html
>
> At least the Gekko Chord and Arpeggio used this hardware.
> Maybe also the Gekko Trigger...
>
> Ciao
> Peter
>
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Ullrich Peter
> Sent: Thursday, April 21, 2011 10:27 PM
> To: Tom Wiltshire; Sam Ecoff
> Cc: sdiy DIY
> Subject: Re: [sdiy] Repair help Waldorf Chord Gekko
>
> Hi!
>
> Interesting that the newer Gekkos use PIC processors as the old Gekko Chord used a 8031 microcontroller and an external eprom...
>
> Ciao
> Peter
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