[Elecraft] [K3] Overvoltage protection?

[Tom Hammond]

Dan:

If the Astron is working AS INTENDED, when the OVP SCR fires, the UA723 VReg
will immediately go into over-current protect mode, reducing the output current
to <1A WITHOUT damaging ANYTHING!  Same as if you placed a short directly
across the output terminals of the supply.

The ONLY time the fuse should blow is if the p ass transistors shorted.

73,

Tom Hammond   N0SS

At 20:28 02/28/2010, you wrote:
>I recently purchased a 35 amp Astron power supply at a hamfest (in 
>great condition).  Upon inspection, I found that the crowbar SCR had 
>failed, and had been removed.
>
>Although I've replaced the SCR, I'm wondering if the K3 has 
>overvoltage protection of some kind?
>
>As an aside, I would like to test the crowbar circuit in the Astron, 
>but with that big capacitor in there, I'm kind of hesitant.  That 
>big capacitor would have to discharge before the primary fuse would 
>blow (maybe blowing the SCR)--right?  I'm thinking of putting a 25 
>amp fuse in series with the capacitor.  Anyone address this before?
>
>Thanks,
>Dan - W4TQ
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