[Boatanchors] TRANSFORMER BUZZ

[rbethman]

Dan,

Check the bolts that go through the laminations at the corners.  They 
"could" be loose.  Also check their mountings.  You "may" have to put a 
rubber O-ring or grommet at the mount points.

Using the output in parallel COULD be problematic.  It really depends 
how close their outputs AND impedances are.  They MAY fight each other.

Bob - N0DGN

K0DAN wrote:
> Hello group...
>
> I have a couple Motorola power supplies (from MICOR Compa stations, I
> think?) which I use in the hamshack to power 12VDC stuff. Big, heavy, 
> "old
> style" supplies (big transformer, big caps, big filter choke...no 
> switching
> supplies here), they work great and are battle tanks.
>
> But the transformers buzz like crazy (and drive me crazy). This is NOT 
> like
> getting a good buzz. Does anyone have any tricks for reducing the sound
> level of the xfrmr buzz???
>
> These units are TPN1110B and a TPN1111B.
>
> While I'm on the topic, does anyone know the differences between these 
> two
> supplies? Spec'd voltage/current output? Any reason I can't/shouldn't 
> rack
> mount two of them and wire their outputs in parallel?
>
> Thanks and 73
>
> Dan
> K0DAN