[Heath] SB200 HV Question

[Kenneth G. Gordon]

On 2 Feb 2017 at 20:51, Jim's wrote:

> 
>     I have finally got my SB200 on the air. The cap´s have been replaced many years ago

"...many years ago...". Has it been used since then? If not, and if they have not been 
reformed, their capacitance has dropped. Yank one and test it.

> but 
>     everything else is stock. My idling HV runs about 1900v´s key down it drops to about 1750V´s. 
>     Line voltage to the amp is off a separate 120 v 20amp ckt. Is this voltage normal?

Well, the READING is not "normal". HV should be 2450 VDC no load, falling to around 2000 
to 2100 VDC under load.

However, I would be willing to bet that the problem is that your metering resistors have 
changed value. I suggest you check those. If they are out of tolerance (and I'll bet they are) 
replace them with a series of 1/2 watt resistors which will equal the total necessary 
resistance, 14.1 megohms. Since 1/2 watt resistors are rated at about 300 VDC, you should 
use at least 9 resistors in series to measure that HV.

I'd use 9 ea 1.5 megohm resistors in series and 1 ea 600K resistor.

Ken


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