Vintage Synth Repair

In a message dated 11/4/05 2:29:54 PM, "timothy kosiorek" <tkosiorek@... 
writes:

<<  I would recommend a good 4-1/2 digit digital multimeter.and a good set of 

electronics tools,I get by without a scope on about 95% of the repairs I do  
>>

Tim,

I'll also have to disagree with the 4-1/2 digit multimeter thing.  A 3-1/2 
digit meter is MORE than sufficient for almost anything one might need to do, 
even on most older analog gear.  The cost difference can be quite dramatic, too.

The well-meaning guy that says you need a 4-1/2 digit meter to calibrate a 
Minimoog is just plain wrong.  A $50.00 (or less) 3-1/2 digit meter will work 
perfectly well.  VCO tuning and calibration should *always* be done by ear (with 
the assistance of a good guitar tuner or strobe tuner), and no meter is 
necessary for that.  The Mini's +/-10volt supplies would have to be pretty far off 
to prevent take the VCO's out of tuning range.  Yes, I know that the service 
manual recommends using a 4-1/2 digit meter, but the service manual is simply 
wrong.  Millivolt accuracy is simply not necessary for that calibration.

It's always useful to have an oscilloscope, but as Timothy says, it's not 
absolutely necessary for most repairs.  The multimeter, however, is necessary.

Michael Bacich