[ZenithDude88]

Hello everyone about 2 months ago I had acquired from of all places my local Goodwill a 1952 Zenith AM/FM Clock Radio Model J733 (according to a rubber stamp on the bottom of the Bakelite Cabinet anyways) Chassis No. 7J03 and its a hot chassis unit (it says on the bottom of the unit Volts 117 AC/DC) and uses all noval (7 and 9 pin miniature) tubes and the clock unit in it is an old Telechron alarm clock unit that has a Buzzer only function and a Radio with delayed buzzer feature and a sleep function and an appliance plug on the back that can be switched with the alarm on the clock and it has its original cord with an early version of the cord clamp antenna that was used on the later Zeniths (where you had a piece of metal that was clamped ontop of a piece of cardboard ontop of the cord that had a spade on it for making your power cord/household wiring into an antenna for the radio).

Anyways This radio was working perfectly hum free as found, the only thing that didn't work on it when I first got it was the clock (which was the usual suspect of a seized up rotor) so I took a known good rotor out of a parts Telechron clock (the clock ran fine but was missing the set stem, hence why it was a parts unit) and the clock works fine now.
But of course when I went to replace the rotor on the clock mechanism on this clock radio something got bumped or disturbed that wasn't supposed to be or something because now the buzzer feature on the alarm clock doesn't work anymore, the radio does but not the buzzer.
If you push the buzzer activation stem in a little bit when the alarm is activated you will hear the buzzer but as soon as you put the stem back into its fully pulled out position (which is supposed to be the position that the alarm is activated in) the buzzer goes silent again.

What I would like to know is what would be causing the buzzer on this clock radio to be non-functional and is it an easy fix or will I need to source a new clock mechanism for this alarm clock? I would like to try and keep this thing as original as possible since this thing was in extemely good condition when I got it (minus a little corner missing on the back over where one of the mounting screws went to hold the back into place which the screw was gone as well) and this is my first Zenith AM/FM Clock radio from the 1950s (I've owned many 1970s vintage units but never a 1950s unit).

Any help would be appreciated, also pictures are attached of the unit in question.

Sorry for the upside down pictures, I was using my cellphone camera and apparently the forum software on these forums hate pictures taken on digital cameras because they always flip the pictures upside down (from what I've experienced on other forums that use similar photo uploading software).