Replacing MicroVAX II PSU With a Modern PSU

[Robert Jarratt]

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Jon Elson
> Sent: 25 November 2015 17:10
> To: General at classiccmp.org; Discussion at classiccmp.org:On-Topic and Off-
> Topic Posts
> Subject: Re: Replacing MicroVAX II PSU With a Modern PSU
> 
> On 11/25/2015 11:01 AM, Robert Jarratt wrote:
> > My reading of the Qbus spec is that P OK and DC OK are active high.
> > That diagram tells me that both control signals are driven the same
> > way because the two circuits are identical except for the timing caps.
> > When the power is OK the output of the inverters is low, so the
> > transistors are off, presumably allowing the signals to float high.
> > When the power is not OK, the inverters are high, turning on the
> > transistors and shorting the signal to ground. But, I am no expert,
> > and could have interpreted those circuits all wrong. Regards Rob
> Yup, I read the circuit the same way.
> 


Ah, I misread your earlier response, I thought you were saying something different.

Regards

Rob