Changing the time

here's a link to THE DEH-P6700MP manualpage 41 to set your clock.

Push function to select Aux. Press Function until Aux appears.

Here is a link to the owner's manual for the stereo which will tell you how to set the time:
http://a248.e.akamai.net/pix.crutchfield.com/Manuals/130/130DEH1800.PDF

Here's a link to the DEH-6700MP manual:

http://fitness.manualsonline.com/mdownloads/e9ea0982-854f-cef4-edd6-86295158c9cb.pdf

How to set the clock is found on Page 41.

That should work for you...

here's a link to THE DEH-P6700MP manual

The 'setting-the-time' function is detailed on Page 41 in the PDF.

I hope that helps

Look on page 28 under Adjusting Inital Settings to select Clock in the inital settings. Now reference page 29, item number 2 to complete clock setting.
http://www.pioneerelectronics.com/StaticFiles/Manuals/Car/DEH-P5100UB_OperationManual1208.pdf

http://www.generalmanual.com/Players/Pioneer-DEH-1600-In-Dash-CD-Receiver.htm

1.press source button and hold until unit powers off
2.press audio and hold until clock appears
3.press -> <- arrows to select hours from minutes
4.0up and down buttons to change the time.

manual can be found at above link ,hope this helps 
Harry

http://www.pioneerelectronics.com/pio/pe/images/portal/cit_11221/192089347DEHP670MPOperationManual.pdf

1. Press FUNCTION until the clock appears.
2. Press LEFT or RIGHT select either the hour or minute
3. Press UP or DOWN to change the setting

Here is the link to the DEH-P3900 website page (sorry is the closest i could find, but changing the clock is the same); http://www.pioneerelectronics.com/pna/v3/pg/support/details/0,,2076_310070337_337273636,00.html You can download the manual from there - you have to register, but it's free. if you want a quick way, pioneer says: "SETTING THE CLOCK How do I set the clock on my single CD player? For most Pioneer single CD players, you can set the clock using the following steps: Press and hold the SOURCE button until the unit turns off. Press SOURCE and hold again until the clock appears in the display. Press the left or right arrows to select the segment of the clock display you wish to set. (As you select the segments of the clock display the segment will blink.) Press the up or down arrows to either increase or decrease the numbers in the blinking segment. Once the clock is set correctly, press the SOURCE button to exit." Hope this helps - please post again if not :)

here is the link for pioneers web site. it has the manyal in pdf form. http://www.pioneerelectronics.com/pna/v3/pg/support/details/0,,2076_310070339_150552934,00.html or press function until clock appears.then press the right or left arrow to select one of the display segments. press the up or down arrows to adjust the time. good luck.