Our HP PSC 950 (admittedly ancient) has been slowly breaking down for the last two or so years. Whenever you try to copy, scan, or fax, the printer will randomly go into a Warming Up mode from which it cannot seem to return.  Zombie mode.

Our when-in-doubt-reboot solution had been to cycle the power numerous times until the printer finally deigned to work. It’s hit or miss that the thing will work on any given reboot. Lately the hit ratio has become frustratingly low.

I was about to throw the printer out the window when I figured I might as well Google “psc 950 problems”. Sure enough, other people are complaining about the very same thing. And sure enough there is a simple solution from a gentleman going by the name tomahawk on fixyourownprinter.com.

The fix? Tear open the printer and wipe dust off the mirror.

I was shocked that this worked. And I have a sneaking suspicion that it will work for other HP printers with similar problems.

Details reproduced here for posterity:

1. Turn off the power, unplug
2. Remove the control panel on the right side by prying off the control box cover with a small flat screw driver, then do the same with the control box underneath (if required).
3. Take off the copy cover, followed by the two small screws at the back/top of the glass cover/scanner unit. These screws are tricky to remove and in the end you might break the plastic in desperation in prying up the cover! Don’t worry, your unit is useless anyway and a couple of missing screws is worth the sacrifice of fixing the copy function. Disconnect the connector multicable, noting how it came out.
4. Pry off the black cover on the copy/scan unit to expose the bulb housing. Don’t touch the bulb, but open the cover of the black plastic housing to the right side of the bulb. This can be a bit tricky too, but will come with a bit of encouragement.
5. With a soft, clean cloth give the mirror a wipe to remove any dirt/dust.
6. LEAVE THE BLACK COVER OFF
7. Reassemble the unit, making sure that the multicable is properly seated.
8. Plug in, turn on and the copy function should work.

Thank you tomahawk. Maybe now I can eek another two years out of this thing.