[sdiy] Prophet 5 Rev 3.1 Power Supply -- Heat Disapation

[klosmon]

The heat is normal -- the P5 power supply runs the regulators at the 
edge of their performance range, and a great deal of heat is the result 
(both on the giant heatsink and the back panel). As long as the heat is 
dissipated, the regulators will not shut down, and the synth will 
continue to perform correctly.

The 5vD supply is set to run about 5.6 - 5.7V (notice the rectifier 
diode at pin 2 of the 5V regulator).

~GMM

On 2/18/2014 2:03 PM, Fuyuko wrote:
> Hello all,
>
> I recently swapped out a noisy transformer (physical buzzing) on rev3.1 Prophet 5 with same type 36V CT rated at 2.8A.  I measured the old transformer output relative to the CT and the new one and the voltage difference is barely worth mentioning.  After installation, I measured all the voltages and they checked out: +/- 5V, -/+15V, 12V, 22V and so on.
>
> Because I am monitoring/mothering the unit for the first few days I have really noticed the heat -- I remember it got hot but it feels hot to touch; it stabilises between 45 and 50C at the regulator nut connections on the heatsink.  I think this is normal but want to make sure.  Also, I noted that the 5V regulator output is 5.77V.  I thought I would investigate but I work on one problem at a time.
>
> Question: Is it running too hot?
>
> What is best practice on a 5V regulator (7805) at 5.77?  Healthy or in need of closer inspection?
>
> The good, the buzz is gone and the unit plays beautifully.
>
> Many thanks,
>
> Bulghur
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