Question about HP LaserJet 4350 Printer

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I'm wondering where the serial numbers for an HP 4350 are located

Kind of an odd question, but hopefully someone here can help. I am wondering where all of the serial numbers are on an HP LJ4350.

Long story short, I needed to talk to tech support at HP. I was at work, and the printer at home. They will not speak to you unless you can provide them a serial number. All I was requesting was a part (see other threads) - they said it was part of the chassis, and weren't sure I could order it. Well, they escalated it to second level support - and yesteday I received a new printer on my doorstep. It's a newer P4015 instead of the 4350.

Well, now I'm kind of stuck in a situation that I need to send them a printer, but mine is not the serial number they are looking for.

I know the serial is on the lid, on the rear EIO cover, and on the chassis behind the formatter board. Anyone know of anywhere else?

I know... I know... probably not the most ethical question, but I'm not sure that I can just send the printer back at this point can I? I never asked for it, but I am worried because I am HP certified, and with my tech ID, they have all of my outlet information as well. I guess I'm looking to take care of this the best way possible while 1) getting my printer fixed, and 2) not jeapordizing my job/status as an HP authorized service outlet and 3) having my boss get on me about working on personal stuff and using my tech ID.

Sorry so long - anyone have any ideas or suggestions?

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Hewlett Packard printers can have their serial numbers reprogrammed in the field, from the front panel of the printer, with very little special knowledge and no special tools. Any electronic page showing its serial number afterward would be divergent from the actual serial number for the machine. It can be changed back again, too - an unlimited number of times.

Yeah, I know - you'll never trust the page count on a used printer again, but there you have it.

This is only true on some of the newer models, and on the larger ones - not the smaller machines like the 1200, but the larger ones like the 5Si, the 4500, etc.

Canon builds the print engines (basic mechanical arrangements of components) for Hewlett Packard, which only really engineers the firmware - which could be used to implement the hidden codes you're investigating. But I would not be surprised if Canon and HP codes look the same and are implemented at a level common to both brands of machine. It is odd to me that you did not publish any pictures of the test prints from the manufacturer which dominates the industry, though...

Since you can alter the serial number (at will) on an HP machine, that could make your decoding task that much easier, if you have access to one. Set to all 1's, all 2's, etc. and compare test prints.

On the other hand, it also makes the entire schema a joke, since I could program my printer to say it is your printer (copy your serial number), print up some phoneybux, and then set it back to innocent_serial and whistle while I watch your office get raided.

The serial number information is soft-coded to allow the formatter board to be replaced if it fails, while still supporting the configuration page's reportage of that printer's vital stats. You can even load the new formatter with the page count from the old formatter, so that the mechanical parts can be maintained on schedule as they wear out.

Now, this is not true of the Formatter Number, which is the serial number of the formatter card itself. If that is the basis of HP's system of Identity, then the workaround would involve a physical removal of the formatter and its (temporary) replacement with another formatter. For someone engaged in producing phoneybux, this is not an economic hardship.

Posted on Dec 27, 2008

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