20 Jan
2012
20 Jan
'12
9:54 p.m.
On 01/19/2012 02:08 PM, Tony Duell wrote:
True, but given the complexity of the monitoring circuit [1], do you really
gain that much by having it. I think I'd just conenct all the supply
lines to a rotary switch [2] and fed them to a low-end 'scope. And then
once a day (or so) trun the swithc round and look at the ripple on each
line.
[1] When I add bits to a classic computer, I try to use compoennts and
designs that were avaialble when the machine was made. So something like
this woudl be done using analogue circuitry. Sampling the supply lien
withaAnd ADC and tryign to measure the ripple that way would not be
somethbing I'd want to do in a classic machine
[2] Make sure it's break-brfore-make for very obvious reasons!
-tony
I am not sure I understnd the point of the
monitor circuit.
[...]
If the capacitor fails open, or high ESR, or
loses capacitance, the
ripple on that supply line will increase. A monitor could detect that,
but equally if that happens, the machine stops working correctly
.
The ripple can increase quite a bit before it causes failures. A
monitoring circuit can catch it before it gets that far.