[time-nuts] Re: HP5061 offline management.

[Charles Steinmetz]

paul wrote:

> Leave just the 3500V supply run. Disconnect it from the internal power add
> a resistor and cap powered by a external switching wallwort in the 1 watt
> range. Brand new meanwell  units are $11. These are medical grade not that
> its required. The resistor is about 470 ohms a 1/4 watt. Dropping 24V to
> 19V. Use a 470 uf cap on the side of the resistor connected to the 3500V
> supply. Ground the negative to the chassis so the I pump meter works.

I may have misunderstood what you are doing, but a 470 ohm resistor 
dropping 19v to 24v will draw from 40 to 51mA, and will dissipate from 
0.75W to nearly 1.25W.

If this is the real operating condition, it's not a happy place for a 
1/4 watt resistor.  You'd really want a 2W or greater resistor there, 
with some good ventilation around it.

Best regards,

Charles