[sdiy] Help bringin Roland SH7 back to life.

[Emmanuel Galvan]

Hi all!

Greetings from Mexico.

I am restoring a Roland SH7, its such a well designed and complex unit and
I am having a lot of fun and learning heaps. I've managed to fix most of
its issues but its 2 VCOs are stuck at a frequency of about 18Hz and cant
make them change neither with the keyboard nor the related knobs or
calibration trimmers. I've replaced timing caps and a couple of
fried ICs, I was afraid it would be the ua 726s transistor pairs on the
exponential converter but I've tried those in isolation and they are
working fine (if I inject voltage to them directly with my V/Oct calibrator
the VCO tracks the frequency accordingly).

Wondering if any of you has had any similar experience or if you had any
tips or pointers?

Thank you very much!
________________________
Emmanuel Galván Martínez
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