Vintage Synth Repair

On Thursday 08 May 2008 15:54, Malte Rogacki wrote:
> http://peterunderdog.com/arp/repair.html
>
> is another starting point.

I *strongly* disagree with a few statements that he makes there,  one of them 
being how tantalum capacitors degrade with age -- that's not the problem in 
the Omni,  running them too darn close to their rated voltage is,  and 
replacing them with 35V units (where the originals were 25V) takes care of 
that.  I also strongly disagree with his assertion that 4000-series CMOS 
parts degrade with age -- there's no basis for that at all,  as far as I can 
see.  He also doesn't impress me as being much of a technician if he smoked 
the power supply somehow (twice!) while troubleshooting some other problem...

> The beauty of the Omni is that large parts of it can be "debugged" one
> after another.
>
> Check power supply and power on boards.

Power supply should always be the first thing you check,  in anything you're 
working on -- if it's not right nothing else will be.

> Check master oscillator.
>
> Check divide-down circuitry.
>
> Check gating circuits.
>
> and so on.
>
> Repair-wise it's really a "one step at a time" synth; and that IMHO makes
> fixing it a bit easier than synths with a myriad on dependent functions.

Yup!

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
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