[sdiy] Roland 80017 findings

[Tom Arnold]

On Wed, Apr 12, 2006 at 01:46:10PM +0100, Heitor Alves wrote:
>    First, congrats for what you are doing ;o) very usefull (at least to
>    me). I have also a Juno with a "broken" voice, but its acting very
>    strange... sometimes it works (some patchs) but others it fails. I've
>    looked in to the service manual trying to figure how to find the bad
>    chip, but i cant understand very well the manual... can you tip me off
>    ;o) ?

Finding a bad filter voice is easy.

Get the Service Manual :
http://www.hinzen.de/midi/juno-106/manual/index.html

Look at page 12 of the service manual and also page 13.
Now, looking at the Module board, the front left corner you'll see two 6pin
connectors labeled TP8-TP13 and TP14-TP19

On page 12 in the bottom table you will which testpoint pair corresponds to
which channel.  Looking at channel 1, TP8 is the output of the VCA ( you can
see this in the schematic if you look carefully enough on page 13 ).  TP19
is the output of the filter Before the VCA.

In my case all I had to do was wait for it to make noise, then scope each
test point until I found it.  Then confirmed that I only saw the noise on
the VCA testpoint and not the VCF testpoint.

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
 --------------------