[sdiy] SCI Pro One 15+ power rail

[Csaba Zvekan]

OK, so the MODE switches are as follows :  Normal , Repeat/Ext , OFF. and the Gate as I'm trying to CV/Gate it with a KENTON PRO SOLO. The GATE LED is always on in this state. But when I switched to KEYB  the gate suddenly responded by the LED ON/OFF. Now that's new from yesterday.I quickly hooked up headphone in the Audio Output but it's dead silence not even slight noise.
 
On 29 Aug 2013, at 11:30, Tom Wiltshire <tom at electricdruid.net> wrote:

> Olav is right to question the Mode and Repeat/Ext switches. My Pro-One has some dodgy switch contacts, and if these switches don't close properly, it's easy to get the synth in an unplayable state. I occasionally have to waggle mine back and forth a time or two.
> 
> I also second his analysis of "probably not the DAC". To say the DAC is at fault from those symptoms is a hell of a leap. It could be any of the VCA, the Gate circuitry, the envelopes, the output, the oscillators, etc etc. You need to narrow that down a lot more.
> 
> T.
> 
> On 28 Aug 2013, at 23:34, Olav Martin Kvern <okvern at ix.netcom.com> wrote:
> 
>> Hi Csaba,
>> 
>> re: "...still no sound with the keyboard played or from the CV/Gate [...] Not sure what the problem is but I'm suspecting the DAC"
>> 
>> If you don't get anything using CV/Gate from the external inputs, the DAC is probably not the problem. I'm hoping that's good news. When you have the middle Mode switch set to Repeat/Ext and provide a gate through the Gate input, does it trigger the envelope generators? Does the Gate LED in that section light up?
>> 
>> If (at some later point) you do find that there's something wrong with the DAC, the AD558 is still in production (according to www.analog.com).
>> 
>> Great synth--mine is still working fine. I walked miles through orchards in 1983 to pick up my tech manual from the SCI office. I'm sure the orchards disappeared long ago.
>> 
>> Thanks,
>> 
>> Ole
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