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<p><font face="Helvetica, Arial, sans-serif">Eric, <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">I spent a lot of time
working with GliGli in the early days helping to test the
upgrade and reviewing the code. Here are some things to try:</font></p>
<p><font face="Helvetica, Arial, sans-serif">Put the GliGli Teensy
back in and pull the two RAMs and the EPROM -- they are not required
and removes them from the equation as mentioned elsewhere in
this thread. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">GliGli does not necessarily
come up with the banner -- but it should be working. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">Next, follow the SCI
P600 service manual
(<a class="moz-txt-link-freetext" href="http://www.synfo.nl/servicemanuals/Sequential/SEQUENTIAL_PROPHET-600_SERVICE_MANUAL.pdf">http://www.synfo.nl/servicemanuals/Sequential/SEQUENTIAL_PROPHET-600_SERVICE_MANUAL.pdf</a>)
and connect a scope to the output of the DAC. You should see
the trace pattern as on p 2.12. If you do not, you have a
problem before the DAC. If you do see an nice stair, pattern,
then the problem in on the analogue board. Play some notes and
you will recognise the traces moving per the EGs or LFO -- poetry
in motion... <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">Now put the original Z80,
EPROM and 2 memory chips back in. Do you see a similar
pattern? If not, your CPU or memory is bad. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">Next, check </font><font
face="Helvetica, Arial, sans-serif">U414 which drives the
current from the DAC to the MUXs. This chip and the DAC are
bottle next through which all the control voltages flow. It
that looks good, then it is time to start "decoding" which MUX
(the 4051s) are bad. Sometimes, they appear fine but they can
be sloppy and cause the unit to fail. It might be good to
compare voltages between different channels for say, the filter
cuttoff and see if they are good. So, for example, if you have
no output from a set of parameters, trace those control voltages
back to see if you find the 4051 that MIGHT be causing the
issue. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">Little by little you should
be able zero in on the problem areas and might come down to a
couple of 4051s. <br>
</font></p>
<p><font face="Helvetica, Arial, sans-serif">I have not mentioned
the front panel but you can disconnect that and then test again.
<br>
</font></p>
<p>Good luck and let me know if I have been unclear.</p>
Bulghur<br>
<br>
<div class="moz-cite-prefix">On 6/19/16 13:13, Florian Anwander
wrote:<br>
</div>
<blockquote cite="mid:5766FD03.5030905@mnet-online.de" type="cite">Hello
Eric,
<br>
<br>
can you disconnect the voiceboard from the CPU board? It should
work alone until the tuning procedure.
<br>
<br>
If it does not come up, then you may try replacing the RAMs. But
this is a shot in the mist. I think of the RAM because a broken
gate would make the CPU stop always at the same point.
<br>
<br>
Florian
<br>
<br>
On 19.06.16 21:31 , Eric Frampton wrote:
<br>
<blockquote type="cite">Hi Florian -
<br>
<br>
The banner doesn’t even come up. It sticks on some random
segments (and sometimes is just blank), and that’s it.
<br>
<br>
e
<br>
<br>
</blockquote>
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