151204-2406 EST
augie47:
From your response to my questions it appears that:
1. There is only one common (ground) path from the computer to anywhere, and that is the shield or common wire in the USB cable from the computer to the printer. This basically eliminates any ground loop path.
2. That you are using a laser printer means there is substantial AC power input required at times. Small laser printers probably are instant on. Meaning fuser power is only drawn during printing, and no keep warm pulse. Small printers use less fuser power because their print speed is slower than large printers.
My HP LaserJet 5MP (a desktop moderately small printer) has a standby power load of about 50 W for the electronics. This printer I describe as having an instant on fuser. Without setting up to check it I don't know the peak fuser power at print start. During printing total power is about 300 W.
My HP 5SiMX is still a desktop, but larger (11 x 17) and faster. Its standby power is about 40 W, and a standby keep warm pulse of 1 second duration about every 10 seconds of about 520 W. Average of this pulse is about 50 W. Total average standby power is about 90 W. While printing average power is about 550 to 700 W.
3. What changed in your setup from when printing worked to now when you have printer printing problems?
4. When your engine is running a fast idle (possibly 1500 RPM) the alternator output voltage at the alternator is probably in the range of 13.5 to 14.00 V. Note engine RPM. Check this voltage when the printer is running and printing at the alternator and the input to the inverter.
When in backup mode (AC power removed) on an inexpensive non-sine wave UPS I read 110 V with a Simpson 270 (average reading calibrated in RMS, 1.1 ratio). An RV AC voltmeter reads 130 V. Both meters on a sine wave read close to a Fluke.
5. What does this statrement mean?
Laser jet 900 watt. The problem is evident on startup, not when printing if that makes a difference.
What is the problem that is evident on startup? And what startup (initial or print start)?
And in relation to your first post?
In conjunction with my work I operate a computer and printer in my vehicle. The printer is powered by a 1000w inverter. Recently the printer shows errors and will not operate on the inverter (it works fine on POCO power) Inverter voltage is 112-117. I thought possibly some type of filter would help. Any suggestions?
Doies it work at all on the inverter?
Tell me if these comments are not clear. I not sure I have said what I want to say.
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