On Sun, 31 Mar 2013 19:53:26 -0700, "William Sommerwerck"
wrote:

The halogen fuser lamp in my HP 4M has apparently bit the dust. (I'll know for
sure tomorrow when I do a continuity check.)

It's a common problem with old printers.
For 117VAC, you want an HP RH7-4046

I looked for replacements. Most companies won't reveal whether they're selling
real HP parts, or third-party units (of unknown quality).

You can get it directly from HP.
http://partsurfer.hp.com
Ooops. No, you can't. So, there are some on eBay and others:
www.ebay.com/sch/i.html?_nkw=RH7-4046
I probably have a few in stock. Bug me via email if you can't find
any. They're NOT genuine HP.

You might also consider a fuser assembly swap. RG5-0879

Getting the fuser assembly out is easy enough. Getting the lamp out
of the fuser assembly is not easy. The heat has probably made the
black plastic ends rather brittle. Brute force is a bad idea. You
may also want to replace some of the plastic gears, which tend to be
worn. Keep your fingers off the lamp. If you touch it, clean the
lamp with 90% alcohol.

hp laserjet 4 and 4plus how to rebuild and fix Fuser RG5-0879
http://www.youtube.com/watch?v=3GLlYoTDlkw
http://www.youtube.com/watch?v=pKdLjU_LAuQ

I just told a friend to toss an HP LJ4 that he had in storage for many
years. Too slow and old. I would get a new printer, but we've been
through this before.

Good luck.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558