Replacement for QP1008 (HP9816 PSU)
dr.emiel at xs4all.nl
Tue Apr 15 03:58:54 CDT 2008
I'm replacing the elco C11 because it's expanding and I suspect it to leak ,
and yes I'm going to check the other components.
I didn't find any open pcb-traces yet but will check this too .
I'll keep you posted on this.
----- Original Message -----
From: "Tony Duell" <ard at p850ug1.demon.co.uk>
To: <cctalk at classiccmp.org>
Sent: Tuesday, April 15, 2008 12:03 AM
Subject: Re: Replacement for QP1008 (HP9816 PSU)
>> I aquired a HP 9816 with a faulty power supply.
> I asusme this is the SMPSU board in the metal case at one side of the
> machine, and not the +/-12V regulators on the monitor PCB.
YES, your right.
>> Thanks to the diagrams of Tony I found out that the switching transistor
>> QP1008 is shorted and a 2n2222 but thats no problem.
> As you've probably noticed by now, this PSU was not made by HP. At least
> in my machine it was made byt 'Power/Mate'. Not that this helps very much.
>> I googled for it and searched my datbooks but can't find any replacement
>> datasheet for it.
> Nor can I. My guess is that the it's a 'house number', and that the
> trnasistor was selected for some particular characteristic.
> My furst guess would be a 2SC1942, since that seems to work in many small
> SMPUS, but don't blame me if it shorts at switch-on. And of course if it
> doesn't you won;t know if that was becuase it was an unsuitale transistor
> or because the origianl fault is still there.
I won't, I'm happy with every suggestion.
> I would certainly check all the secondary-side rectifiers and smoothing
> capacitors. And the snuber componets (R6, CR4, C12, C3, CR5)
> I assume that some of the low-value resistors in the Q2's emitter circuit
> have burnt out too. Any open PCB traces?
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