My iphone keeps buzzing and shows an icon of the ringer with a slash thru it it wont actually ring, just vibrates altho the ringer is on

check your settings SOUND and see if the slider is all the way to left. Also check icon and see if there is a slash through it. If there is a slash, tap it. Should then be able to ring/

Check to see if your silent button is switched off - should be on the upper left side top corner or you're volume for your ringer is turned all the way down and finally, in your settings - check your do not disturb setting.

If you're missing incoming phone calls due to your iPhone not ringing, you may have accidentally switched the ringer to vibrate or silent, according to Apple. The switch on the left side of the iPhone turns off the ringer and usually sets your phone to vibrate mode, but if your iPhone's vibrate setting is also disabled the phone will instead be set to silent mode. When in the phone's sound settings vibrate mode can be enabled, and the ringer volume of your phone is adjustable.

Read more: My iPhone Will Not Ring ' eHow.com http://www.ehow.com/how_7384812_iphone-not-ring.html#ixzz22OJOMZGR

hey bro,
i fix more problem like your's. by change the flex up. with volume+vibrat button+headphone.
change this and all your problem will be good.
memeh Fixphone

I would try a system restore, plug your iPhone into iTunes and click restore, it will delete everything but once its done it will restore it to when your last sync was.

There's a switch on the left side at the top of the iphone that turns the ringer on and off. Make sure this is towards the front of the phone to enable the ringer

when you set the ringer to ring only will it ring?
on the side of your iphone there is a switch above the volume switch that is a ringer/vibrate switch
switch it and test

firstly read the operations manual for that phone look on how to adjust the settings of your phone it probably sure was indicated there, because the way i see from what you posted it has no internal circuitry prob. it just needed an adjustment.. hope this advice helps... ;-)

Per the manual, If there is a musical note in the display with a slash thru it, you have turned off the ringer. You have done this by pressing and holding the # button.
If you have the manual it's on the bottom of page 20 and continues on 21.
If not follow these steps.

Press Menu
Press CID/PBK (Personal set)
Press Menu (Handset Tone)
Press Menu (Ring Tone)
Press Menu and then CID/PBK to select the volume you want
Press Menu (Save Setting)

click this link to get the manual

http://www.p4c.philips.com/files/c/cd4452b_37/cd4452b_37_dfu_aen.pdf

you can actually move the button , on the top left hand side of your iphone, over the ringer volume, you will see a red or orange dot, this means the switch has you iphone in silent mode, I was stuck on this, until I found it is a actual switch, look at it closely, you can move it. So where you see the red dot, put your finger on it and move it the opposite way, and I do not mean press the button, I mean, flip the switch on it, then your phone will not be in silent mode anymore,,, this was very annoying, I hope it helps anyone that has the same problem.
cheers!