[sdiy] Prophet 5 weirdness.

Randel Osborne randel at redshift-consulting.com
Wed Mar 16 16:44:21 CET 2016


Jim-

Jim-

The Prophet 5 power transformer has a center tap on the secondary side that should be tied to case ground.  The AC input ground should also be physically connected to case ground, as should the outside conductor of the 1/4" jacks.

This can be verified by inspection or by using an ohmmeter - please remember to disconnect from AC power first!

In the event that one or more of these connections has failed, it might cause the symptoms that you described.


-Randel








> On Mar 15, 2016, at 12:32 PM, Jim Blair <ceratos at shaw.ca> wrote:
> 
> Yeah, remember that this P5 is a "brain". So a bunch of work was done on it, who knows what went down, and how long ago. 
> 
> But something's up in there. Now that I have a pretty good grasp of the symptoms, I'm going to talk to a local tech today. I'll report back with the results.
> 
> 
> Jim
> 
> 
> 
> 
> 
> Could it not also be swapped primary lines in the P5?  Has the 
> transformer been swapped out?
> 
> On 3/14/2016 7:15 PM, Jim Blair wrote:
> > The mysterious P5 problem has been tracked down. I can't say for sure
> > that we know where exactly the problem lies, but I have called an
> > electrician to come and have a look at potential grounding problems in
> > the studio.
> >
> >
> > Basically, I ran the P5 into a DI with the ground lifted. Worked
> > perfectly. Then I checked it un-lifted. P5 freaked out.
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