Unanswered: How to turn off the touch screen light of a HP Officejet Pro 8500A ?

[dqmcg]

Since the printer and the router are using a 2.4Ghz signal to communicate and if you have a 2.4Ghz cordless phone I could see this happening as all devices would be usinfg the same signal.

So the question would be...do you have a 2.4ghz cordless phone and have you try moving it as far away from the router and printer as to not cause interference.

[dqmcg]

The issue you are having is expected behavior. The only way that you can really get around it would be to get dedicated lines for both the fax and the phone. 

[itguy08]

Well it looks like on my 8500A that if I have it plugged into the phone line it will keep the LCD on.  I originally thought it was my cordless phone which shares the line with the FAX machine but I plugged the 8500 right into our phone line and the display stayed on all night.  We did not get any phone calls overnight.  Unplug it and it went off within 10 minutes.

I do have the latest updates for it so maybe it's a bug?  Is there a way to officially report this to HP?

[dqmcg]

You can try sending an email to the support team to get this issue logged. The link is provided below.

http://h10025.www1.hp.com/ewfrf/wc/weInput?product=4083969&lc=en&cc=us&dlc=en&tmp_weDest=https%3A%2F...

[fyuta]

is there a resolution to this problem yet?  The lighted display never turns off.  The only way I can turn it off is to turn off the power button.

[fyuta]

I am curious why this thread was flagged as having a solution.  I have tried both the on and the off settings.  The on setting runs an HP commercial, the off setting does nothing.  The display stays on continuously.

[fyuta]

further debugging info, it appears that problem is linked to any phone use.  If you make or receive a call, the display lights up.  This is quite an inconvenience if you use the HP Officejet Pro 8500A as part of a home office where you share a line with a phone.  I rarely use the fax, so I will do a workaround by disconnecting the phone line and only plugging it in when I have to send a fax.

I hoope this helps other resolve the problem, but this is only a workaround.  The easiest one I can find.

[dragonway]

Have the same problem...Found out it was the fax line that would active the screen. Solution..unplug the fax line....I don't receive many faxes (home printer) so it minor problem. I think stray current on the fax line actives the screen making it beleive a fax is coming.

[Hopped]

Screen light never goes off, solutions don't work as I have no fax or phone line in. Any other hints how to make it dark? Thanks!

[MKupper]

@Hopped, I would debug "Screen light never goes off" by setting the system mode timeout to a low value such as five seconds. The display should turn off and the printer will go to sleep five seconds after you pressed any button.

To set the system mode timeout. Press * and # together. The printer will prompt "Enter special key combo". Enter 1 2 4, poke the left arrow twice to get to System menu, poke "Ok", poke left arrow once to get to System mode timeout, and poke "Ok" once again. The printer will display "System mode timeout = ### seconds". I believe the default timeout is 900 seconds which is 15 minutes. Use a timeout value of 0 (zero) to disable the idle timeout feature meaning the display will always be on.

For testing, use 5 seconds. Do not try testing with a much shorter value such as 1 second because if you hesitate for one second while navigating to and setting the the system mode timeout the printer will go to sleep on you and you will need to start over with trying to set the timeout.

If the display remains on then update the firmware if you are not already at DLM1FN1344AR.

If the display still remains on then disconnect the phone/fax line, Ethernet LAN line, and disable the wireless. (I know in Hopped's the there is no fax line but I assume others may have the same issue).

If the display still remains on I'd guess one of the buttons or sensors is defective. You could try moving the printer to another location to see if it's a power issue.

FWIW, the printer uses 7 watts when idle with the display on and 5 watts when it's sleeping. It uses 1 watt if you power it off (see note below) but as a power on causes a printhead cleaning cycle which uses a lot of ink I don't recommend powering the printer off unless you plan on not using it for several weeks or months. I believe when you power it off the print heads are parked in an area that seals off the heads so that they don't dry out as quickly.

I have the system mode timeout set to 60 seconds on my printer meaning a minute after done using the printer it goes back to sleep. I could not detect any difference in how quickly it starts to print whether the printer is sleeping or awake. In other words, it wakes up instantly does not not need to warm anything up or do any other preparation before it's printing.

The reason I don't use a very low value such as 5 seconds is I don't want the printer going to sleep on me when I'm getting ready to do a scan to network folder or e-mail. If I paused for a few seconds to think about which e-mail or network folder to use the printer goes to sleep and I'd need to start all over.

While some people suggested adjusting the Energy Save Mode setting under Preferences this only changes the printer's behavior when it's powered off. When Energy Save Mode is enabled the printer uses 1 watt when powered off. When it's disabled the printer uses 5 watts which is the same usage as when it's sleeping. However, when I tested with Energy Save Mode off the printer seemed to do a full boot and also did a printhead cleaning. See http://support.hp.com/sg-en/document/c02064489 for HP's explanation of Energy Save Mode.

Note that my comments are about an HP OfficeJet Pro 8500 A909g (model # CB023A). The comments apply to both firmware version DLM1FN1006BR and DLM1FN1344AR.