Flex Disc options for the HP 9825

Jos Dreesen jos.dreesen at bluewin.ch
Sat Aug 13 11:51:38 CDT 2016

On 13.08.2016 11:37, Rik Bos wrote:
> For what it's worth a small warning about the HP 9825 series computers.
> The power supply doesn't have a crowbar(over voltage protection), so a
> transistor failure in the Psu can be catastrophic.
> On the other hand the two 9835's I have, which uses the same form factor and
> almost the same power supply layout are HP modified with crowbars added.
> It seems to be good practice to add some ov-protection to the HP 9825 supply
> because the switching transistor and 723 voltage regulators don't have the
> eternal life.
> And there no certain prediction in how they fail, short or open circuit, I
> found out the hard way several years ago.
> -Rik
The same is true of the PDP8/L. I also found out the hard way....
That L is still not running, but the PS now has a crowbar !


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