Most likely the baking helped with either a moisture/conductivity problem, or with a thermal intermittent. Two problems in PCB manufacturing came along at almost the same time -- the switch to brittle, lead-free solder, and the switch to water-soluble flux. I've seen problems caused by both issues that could be "fixed" by baking.
If you have a cracked solder joint, the only permanent fix will be to find it and re-solder it with good solder. Typically, it's heavy components with large tabs that have the soldering problems, both because the thermal mass of the heavy part tends to result in a cold solder joint under the best of circumstances, and the weight of it exacerbates any vibration or thermal expansion problems, which can crack brittle solder. An engine control relay module in ~1990 Honda Civics was notorious for that.
If conductivity is the issue, if the device is kept in a warm dry environment henceforth, it may be fine. If not, the best solution is to scrub the board with warm, soapy water and a soft brush, blow it dry with clean air, bake it to drive out remaining moisture, and if operation over a wide range of temperature or humidity is expected, spray both sides with two thin coats of a conformal coating. Ordinary clear acrylic enamel can be used, but I prefer the silicone coating for its flexibility.
In 1987 I started a small business and purchased a HP Laserjet Series II Printer. I used it heavily at first and it worked well. A few years later it was out of warranty but I got a local fixit place to repair something on the motherboard that had failed. Later I replaced a damaged platen that cures the toner. The first repair was $100, the second $26. The business closed but I kept the printer. I am still using it now, having gone through 8-10 print cartridges (10,000 pages per cartridge). The majority of my printing is documents and it still puts out a clean page. A little slow, but I am not in a hurry. It is now 24 years old and the current cartridge cost $90, but it is least the last 4 years and still doing well.
Planned obsolence - I think that is too much credit to our fellow marketers.
As much as RoHS has become a necessary evil, it remains an evil. Tin Whiskers are going to haunt us until someone determines its cause and a means to end it. NASA's link: http://nepp.nasa.gov/whisker/reference/tech_papers/2011-kostic-Pb-free.pdf desribes how 'bad' product can suddenly be good as arching removes the 'short' caused by tin whiskers. I suspect there are many issues occuring that are blamed on people that are caused by lead-free electronics - Check out NASA's report on the Toyota sudden acceleration cause.
So the next time you have a 'bad' electronic device, take it apart and hit the electronics with some compressed air - you will probably save yourself some serious dough. Just remember - the problem will come back....
1) Have a OKIDATA ML 391 wide-carriage printer connected to a DELL 486/33 PC that I still use for one program. PC & Printer are over 20 years old & still working!
2) Also have a H-P IIIP laser printer which I alternately connect to the DELL 486 or to the DELL TOWER w/ WINDOWS XP PRO. Still works, after 20 years, BUT I did replace the laser motor board assembly about 6 years ago. The kit came w/ a new board assembly AND a VCR tape w/ EXACT tear-down, remove, install, re-build instructions. Just bought a new (NOT replenished!) toner cartridge from an outfit in California. Was about $40.
3) Did considerable p.c. board design work several years ago using EAGLE software. So, I needed a color printer for checking the layouts. Bought an EPSON printer from OFFICE DEPOT. Was less than $100. Used it, but had some install problems (drivers, etc.) Needed to go to EPSON website for updated drivers. Worked OK after that. After only about 18 months of use I didn't need it anymore, so it sat next to the PC. When I tried it again, the ink wouldn't flow. Tried their built-in Diagnostics, and Printhead cleaning routine several times. The ink was too caked. Then I remembered that I had a 2 year warranty from OFFICE DEPOT. With only one month to expiration, I brought it back to the same store, filled in the paperwork, and received ALL my money back, including the sales tax. That was the BEST part of owning an EPSON printer.
I am also an avid amateur photographer, who shoots digital AND film. I hesitate to purchase a decent photo quality printer for several reasons, mostly I'm afraid of spending a sizable amount on the printer (CANON has some real doozies!!), only to see the printheads get permanently plugged. For images which I want to publish, I do the same as RATSKY suggested..... downloading them to a drive or to the photo shop for printing on their high-end machines.
I'd be interested to learn more about lead-free solder and how the rest of the industry is dealing with it. When RoHS was first implemented, everyone had solder issues, but now all of our suppliers have what appears to be a stable process and rejects due to solder have dropped off the chart completely.
A very interesting series of comments and experiences with (mostly) HP printers, end-of-life(EOF), planned obsolescence, bad solder joints, et al. For my own part, I have had pretty good luck with HP printers. Our 'main' printer is an HP LaserJet 1012 which we have had for more than 4 years. We about 2 toner cartridge's a year for a mostly personal/small business - printing mailing labels, articles, etc. Printer has never given us a lick of problem.
We also have a Epson All-In-One color inkjet scanner/printer which we use mainly for photograph printing (on the printer side) and as a scanner (very handy). Cost a thumping $90 some 5 years ago, very lightly used and very reliable. We lose most of our ink to just age rather than use.
Frankly I would never buy a printer with the idea that it would be my 'last' printer and hence I would never spend very much on it. Darned market moves just too fast. I remember spending way to much money for a Diablo dasiy wheel printer - bit, bulky, slow - you name it. Finally just gave it away to a collector.
A note on color printing - you might want to consider the use of the many commercial outfits such as SnapFish. We use them (or someone similiar) any time we need multiples, specials, etc. Only takes a week or less and cost is usually quite low. Much less cost than trying to have a super printer around.
Re-flowing solder on a failed board has been done for video cards for several years now. the procedure is to remove anythng that may be damaged by the heat, make small balls of tin foil and place the board on a cookie sheet, spaced away from it by the foil balls on the screw holes in the board. Bake and test. It is hit-or-miss, but in most cases not trying it leaves you with a paperweight.
I've had success with the baking technique, not once but twice!
The first was a Lenovo Thinkpad T60 laptop with a graphics problem that made the display unreadable. Internet research confirmed that the cause was likely a solder connection problem with the graphics chip. Baking the motherboard got the computer running for a few more weeks, enough time to buy a replacement.
The second success was an XBox 360 with the dreaded "red ring of death", a well-known solder problem. It was out of warranty so I figured I had nothing to lose by baking the motherboard. Not only was it revived, it is still working six months later!
I have to admit I'm baffled by the tales of HP quality (or lack thereof). About 15 years ago, Design News gave its annual Quality Award to HP for their efforts in printer technology. A few years after, I started hearing horror stories of HP printers and their low quality. But I have two HP Officejet 5610 All-In-One printers that are both around eight years old (I think); I've never had a single problem with either one in eight years.
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