IP-32 & variants

[Terry Perdue]

Happy Easter to all!

I just rebuilt one of the later versions of the IP-32 High Voltage regulated
supplies. (I don't remember the model  number, as I tossed the ugly old
cabinet and built it into a nice new one.)

The schematic I built from was for the IP-32. Catalog copy for the IP-32
included the statement, "Built-in protection prevents damage to the power
supply should the bias voltage be accidentally shorted". Well, that
'protection' turns out to be a 22K resistor in series with the bias output.
The problem is that, when the voltmeter is switched to display bias voltage,
the 150K 1% resistor in series with the meter in that position forms a
voltage divider with the 22K, changing the bias voltage. So when you switch
the meter to display the high voltage output, the bias voltage will rise by
as much as 20V. The obvious solution would be to remove the 22K protection
resistor and be careful not to short the bias supply, but I'm wondering if
this got changed on later versions, and if so how?

Thanks in advance for your help.

Terry Perdue

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