Li@USCN.BITNET (LI Jialin, UGA Physics) (02/21/90)
I have a LaserJet+(call it LJ No.1) needed a new fusing roller, so I
bought one from HP and replaced it myself. However it does not work. I
than took the whole thing(everything on fig.A) off, put it on another
LaserJet+(call it LJ No.2), it worked. Place it back to LJ No.1, still
wouldn't work. After a while I remembered that when error #50 first time
come up on LJ No.1 was because the connection of fusing bulb was open
(but after I connect it, the error #50 keeped coming up anyway). I did
waite 7 min before every power up, and did reset the AC Circuit Break
on the AC power supply.
To find out why, I repoduced(not intentionally) the same error #50
on LJ No.2, and the reason is the same: disconnect the AC power supply
to fusing bulb. Here is how I did it:
============================================================================
LaserJet+ No.2, works fine
AC thermo-protector AC (Note:
| [O] [OO] thermistor | thermo-
| .----------------------------------------------------. | protector
| : ___________________________________________ : | wired in
|-------|___________________________________________|------| seires w/
: fusing bulb : fusing
`----------------------------------------------------' bulb)
fusing roller
fig.A
=============================================================================
Power off, disconnect one side of the fusing bulb
AC thermo-protector AC
| [O] [OO] thermistor |
| .-----------------------------------------------------. |
| : ___________________________________________ : |
|----\ \-|___________________________________________|------|
: fusing bulb :
`-----------------------------------------------------'
fusing roller
Turn power on, error #50.
fig.B
============================================================================
Power off, reconnect it (as fig.A), wait more than 7min, power on. It
passed self test, and waited for 90sec, error message #50.
Now I have both printers dead and need anyone's help badly.
Thanks for any help in advance.
Jialin