HP LJ 5550 Dead

[jagamon]

Say guys,

I got sent out to work on an HP LJ 5550 today. One of our other guys had already been there and ordered a power supply for it - I had no prior knowledge of it, only that the customer said it smelled funny and stopped working. Anyway - I replaced the power supply, even though I couldn't detect any semiconductor smell coming from it. What do I know? I powered the thing on and it's still dead. I checked the fuse on the power supply board and it was blown. (as was the fuse in the original) I have absolutely no experience with this machine at all, and the little experience I have now has been all bad. Any thought? Fuser? HVPS? Fuser power supply board? (first time I've even seen on of those) Any help will be greatly appreciated.

Many thanks,

Jeff

[blaze2000]

Well man, dead is about as vague term as we can get. I mean I'm not bagging on you but really... what happens when you plug it in and hit the power switch, nothing, beep, display falshes, etc... if nothing, which I'll assume is the symptom... ok check the power at where the plug goes into the machine do you have correct voltage? If yes then check the voltages from the ac board to the components.

I would check the fuser yeah, but if your display is dead that is probably is engine control board or pca (I think thats what they call your main board)

[jagamon]

Sorry - I thought dead meant dead. No lights, no sounds - nothing. And as the main fuse is probably 1 or 2 components the other side of line voltage there isn't much chance of tracing anything through the power supply. (or anywhere else, for that matter) I just thought maybe someone had run into something like this before. My only thought would be to replace the fuse, disconnect the line going to the fuser power supply board and see if there's any life in it then.

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[blaze2000]

Was just verifying to be certain it is really dead. So long as your getting AC to the PS board, next check your power (on/off) switch to see if your getting juice to it and it is functioning correctly.

[jagamon]

Hey man,

Look - I know you're trying to help, but HP's often have a life of their own... and that's why I posted the original query. I started working on HP's when the LaserJet III was in production. I even went to the Canon school in Irvine CA. If the machine had a defective power switch it most likely woudn't be blowing the main fuse, unless the power switch was a double-pole double-throw job that had somehow fallen apart and was shorting the input... No - I don't think that would blow anything other than the circuit breaker to the power outlet it was plugged into. BTW - the power switch on these machines is part of the low voltage power supply so that was replaced with that part. Good news is I fixed it today, by replacing the fuse on the low voltage power supply board, the fuser and the fuser power supply board. I think the only thing that was actually wrong with it was that the fuser had shorted out somewhhere, and that took out the main fuse. I wasn't taking any chances though. Thanks for all your help.

Cheers,

Jeff