[sdiy] Solved: Crumar Performer - keyboard mystery

Kenny Balys kenny at beatkamp.com
Sat Aug 4 17:37:28 CEST 2018

Thank you for that info, and congrats on the fix.

On 04.08.18 15:24 , Florian Anwander wrote:
> Hello
> I solved the funny behaviour of the Crumar:
> The problem was caused by a too high voltage on the keyboard bus, which again
> was caused from the "Crescendo"-circuit, which has a trimmer for offset. This
> trimmer is soldered on the soldering side of the pcb and should get its ground
> from a line on the component side of the pcb. Appearently the connection on the
> not easily accesible parts side was missing, so I connected the visible side of
> the solderpoint with a wire to ground and now everything is fine!
> Florian
> Am 31.07.18 um 21:04 schrieb Florian Anwander:
>> Hello,
>> I have here a Crumar Performer for restauration which shows a strange
>> behaviour over the keyboard:
>> In string mode some keys have an rectangle suboctave playing and some don't.
>> It does not matter whether I am in 8" or in 16" mode or have both activated.
>> In brass mode this suboctave is gone.
>> There is no octave relation, which might have made the TDA1008 suspicious.
>> Interchanging the TDA1008s also does not move the behaviour to other notes.
>> The service-manual is here:
>> http://www.florian-anwander.de/crumar_performer/CrumarPerformerServicemanual.pdf
>> The datasheet for TDA1008 is here:
>> http://www.florian-anwander.de/crumar_performer/TDA1008_PhilipsSemiconductors.pdf
>> The list which note has suboctave and which not:
>> http://www.florian-anwander.de/crumar_performer/CrumarPerformerSuboctave.txt
>> I have no idea where this suboctave might come from. Any suggestions?

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