Can you diagnose this electricity problem?

[radhak]

This is not in the 'shop, but in the house. But still.

Observation : when I put my Brother Laser printer on (2170-W), the room lights flicker, and do so intermittently all the time it is on. Done that for the past 2 years, and I've lived with it. I surmised it was pulling in more power than it should, for whatever reason. I just thought I wouldn't try to fix it till it became a pain.

Recently, it has : it flickered, and the computer rebooted. Happened yesterday, when I hurriedly shut down the printer. Did it again today, twice; at which point I investigated : looks like I had plugged the printer into the 'surge protector' side of the UPS (while the computer is plugged in the 'battery backup' part of it). But it has been so all along, so why is it misbehaving now? Maybe the UPS has conked out, and is now just a power-strip (it's 5 year old)? Maybe till now the UPS was protecting against the surge, or even a trip, and is unable to, now?

So maybe I could buy a new UPS and everything settles down. But don't you think the printer has some serious problem? Drawing more power than any appliance - even my DC or TS at startup - and that not just at startup, seems to me a worrisome thing.

Anybody care to comment on how you see this? Do you think I missed something?

I have not yet tested it by plugging the printer straight to the wall - the only socket nearby I can see is used by a surge-strip that powers my cable modem, so to test it I will have to use a far-away socket, somehow. Will try, but do you think it might trip some fuse somewhere at the panel?

[twistsol]

I can't answer your question, but I can tell you a little bit about how laser printers work that might give a little insight into the power draw. I'm not familiar with the model printer you're talking about.

The laser shines on a photosensitive drum and charges it which picks up toner in the spots where it is charged. The paper then passes between the drum and a high voltage wire in the transfer assembly which has a greater charge than the drum and pulls the toner from the drum to the paper. Finally, the toner is melted or fused onto the paper by the fuser roller.

Older laser printers had a 4-800 watt halogen bulb inside the fuser roller which comes on and off periodically to heat the roller. This is the part possibly causing the flickering and in printers that aren't energy star compliant, the fuser is hot whenever the printer is on.

Newer printers let the fuser assembly cool down when the printer is idle but in order to have quick first page out time heat up really fast, and therefore high but brief power draw.

[LCHIEN]

twistsol is probably thinking on the same lines as me. His discussion of laser printer is correct. They tend to draw brief amounts of high current to heat the toner fuser assy. IN some cases this could be several Amps - hundreds of watts. The draw could last a second or 2 or 3. If an energy saving model it would be when you printed only, but older models or new models with instant on could do it at anytime to get quicker initial printing.

If you have a lossy connector or section in your wiring (on the order of 2 ohms), shared with the computer the surge of current could cause momentary drops of 10's of volts. This could cause a computer to reboot or monitors to flicker, UPSes to transfer.

Is your UPS working right? Unplug it from the wall and does the computer continue to run?

Try plugging the laser printer into the outlet shared with the UPS, but not into the UPS. If the problem clears up then you have some weak wiring in the UPS to the surge protected socket where the laser was plugged. If the problem persists, then your wall socket may be lossy, or it could be between the breaker box and the outlet, requiring an electrician to fix.

[gerti]

5 year old UPS? Battery is more than likely shot. Shutdown your PC, unplug the UPS from the wall, and try to start up the PC. If it doesn't the battery is gone. Either replace the battery or get a new UPS. I never had much luck with replacing batteries, seems the electronics in most consumer grade UPSes (I tried several brands) have a similar life expectancy than the batteries...

The laser printer is likely causing a brownout, and if the UPS has a dead battery it can't ride it out and hence your PC briefly looses power.

[Slik Geek]

Aging UPS

I have the same Brother Laser printer (HL-2170W). It has an unusually high surge current when it fires up the fuser. It dims the lights in my home office and rattles the conduit. (The peak current is so high that the magnetic field causes the wires in the conduit to move, resulting in the conduit rattling).

The lamp filaments have a very low resistance when cold, so when they are first powered, they appear like almost a short circuit on the AC mains.

The designers of the printer could (and should) have done a better job limiting the peak current - but perhaps were cutting costs and left out the components necessary. Otherwise, I've been very impressed with the printer - and would buy another.

When the printer fires up, the line voltage droops severely, causing the UPS to kick in to maintain the line voltage.

I suspect that your UPS batteries have aged, resulting in either:

1) A severely reduced battery capacity, meaning the UPS can't do its job any more.

2) The batteries internal impedance has increased so much that sufficient current cannot be drawn from them to operate the UPS. (At lower current loads, the batteries might work fine, but under heavier loads, the batteries just can't keep their voltage high enough).

Either way, the batteries need to be replaced in the UPS (assuming that the UPS is still functional otherwise).

[Just saw that Gerti has basically answered your question well...sigh]

[pelligrini]

I can't add much and I agree with the previous posters. What sort of other loads have you got on that branch circuit? It sounds like you're getting close to capacity, especially with the large intermittant loads from the laser.

You did right by not having the laser on the battery side of the UPS. Lasers are power hogs and they don't really need to have a battery backing them up. You might check out RefurbUPS.com for replacement batteries. Their prices are reasonable. I've used them to replace some batteries at home and a mess of them at work.

[Kristofor]

I'll add to the chorus of agreement but will reitterate pelligrini's comment about not running a laser printer off of the battery side of the UPS. Doing so has frequently caused soho sized UPSes and/or their batteries to fail (though at 5 years battery replacement would be expected anyhow).

That said, a printer that dims the lights regularly when operating probably isn't doing any favors to the rest of your electronics either. It might be worth considering a replacement the next time you run out of toner...

[radhak]

So I finally managed to check today : the battery of the UPS is fully shot. I was thinking I needed a new UPS, but pelligrini's link gives me hope I can just buy the battery and save some money.

I had no idea Lasers draw so much power. I just plugged it in directly to the wall, and the lights keep flickering, but at least the computer is not forcibly restarted! So hopefully once I get the battery changed, I could plug it back to the UPS (non battery side) and not have these flickers or worse.

But I do love the HP2170-W. Its drum seems to go on forever! And it is both fast in starting, and in printing. My Canon MP530 could never compete. I will stick with this laser for some time, and try and contain the damage it does with its high power draw!

[LinuxRandal]

I had an old Kyocera laser printer that caused the lights to flicker. It was an EARLY one and I took it over to my dad's due to how much he was printing (WAY too much in ink costs).
For some freaking reason, he decided the per month rating, meant he needed to print that much.
After mom and I had a discussion about it, I brought it home. The toner cartridges for it, had got to the point of an inexpensive laser printer. So when I could and I was due, I picked up a Brother HL1440 (been some years ago now). I get NO light flicker with it. I was unhappy thought the other day, I thought my printer was TU. (couldn't get the jam lights to shut off) I had just put in my third toner on it and felt like I was wasting money. I was able to clean and fix it (spring on a feed roller, seems to be the issue).
I would happily by another (already have an idea for the replacement, just in case).

[LCHIEN]

that Brother HL1440 was a great little printer. I used it for years and then ave it to my mother who needed a reliable printer. I got a Brother laser printer scanner copier and its been nice, too.