DEC H745 regulator common failure modes?
billdegnan at gmail.com
Fri Nov 27 15:14:33 CST 2015
On Fri, Nov 27, 2015 at 1:09 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:
> > There is a pdp 11 troubleshooting guide on Bitsavers that covers the h742
> > powersupply and regulators 744. 745, 754. Assuming that is what you
> > They're all tough to work on especially the regulators but I agree with
> > Tony that you need to lock down the main suppl first.
> I am not sure what you mean by 'tough to work on'. If it's a physical
> problem then what I did was to obtain a spare 8 pin mate-n-lock plug and
> socket and make up a pin-pin wired extension lead about 1m long. Then I
> can take the brick out of the PSU, connected it via the extension lead and
> able to probe it. I normally sit it on top of the CPU box of my 11/45, you
> easily enough air flow from the fans to run it for testing.
> If it's that the circuits are complicated, well, remember these are
> regulators (not linear) but are a lot more repairer-friendly than most
> in that nothing in the brick is directly connected to the mains.
Tough-sh to physically work on/test. These are not made for field service
IMHO, just swap out part.
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