laserjet IV 50 error message

[Gregg Hannah]

The fuser won't heat up even though the cables, connectors and ohms test OK. Also the main motor won't activate when the machine is turned on even though the voltages test OK. The gears all turn freely. What to do? :confused:

[ptjeff1]

Sounds like you might not be waiting long enough for the 50 error to disappear. When the 50 error appears you need to wait at least 10 min. for the capacitor to discharge.

From the service manual, "The 50 SERVICE error message can be cleared immediately by shorting the C202 leads on the HP LaserJet 4/4M (or the C205 leads on the HPLaserJet 4 Plus/4M Plus/5/5M/5N) on the DC Controller. Remove the Formatter PCA to access the DC Controller as shown in Chapter 6".

[pinhead]

If you need parts, the 50 service is usually either a Fuser or an AC Power Supply. If you try to clear the message by turning off/on, you must leave printer off for at least 10 minutes. good luck.

Matt