[sdiy] MKS70 power supply issue

[Paul Anderson]

I just had a funny thought. Does your multimeter read RMS or peak-to-peak?

If its reading peak voltage, and the 7v line is pulsating DC, then the meter will read 10 volts. 10 volts peak is equal to 7 volts RMS. if you can, put an oscilloscope on that supply and see how noisy it is. 

Sent from my iPhone

On 2012-11-14, at 11:12 PM, james meagher <w.james.meagher at gmail.com> wrote:

> Paul wrote: What does it power in the rest of the machine?
> 
> It looks to me like it's going to the Jack board where it would
> perhaps feed a PG800 were one plugged in (I don't own one), and also
> to somewhere on the assigner board, but my copy of the service manual
> is so blurry on the assigner board schematic I can't really tell where
> it's going or what it's doing once it gets there.
> 
> Mark wrote: Is that measurement unloaded? Because that supply line is
> unregulated, it will likely droop when it's loaded. Maybe 3 volts...
> 
> I've got everything plugged in, the machine is receiving MIDI and
> making sound and this out still reads 10V on the dot. But if it's a
> PG800 it's looking for I can't help it there.
> 
> Cheers,
> James
> 
>>>> 
>>>> You can see the schematic of the PSU here:
>>>> https://www.dropbox.com/s/jstusojn3610cf6/RolandMKS70PSU.jpg