The Alwars (also spelled Azhwars) are a group of 12 ancient Vaishnava saints who lived in Tamil Nadu and are famous for their poetry in praise of Vishnu. The 4000 verses of the Alwars were compiled by the Vaishnava Acharya Nathamuni into a book called the Naalayira Divya Prabhandam, which is considered by many to be the "Dravida Veda", or South Indian Veda. The Alwars are crucially important figures in the history of Vaishnavism; it is the principles and beliefs embodied in the Alwars' poems that Nathamuni used to found what we now call the Sri Vaishnava sect (of which I'm a member).
Now as I discuss in this question, Sri Vaishnavas believe that the Alwars are incarnations of various attendants and attributes of Vishnu; for instance the Alwar Nammalwar is considered to be an incarnation of Vishwaksena, the general of Vishnu's army. And as I discuss here, the first four Sri Vaishnava Acharyas are believed to be incarnations of various attendants of Vishvaksena, and Ramanujacharya is believed to be an incarnation of Vishnu's serpent Adiseshan as I discuss here. But now I'm interested in another Sri Vaishnava Acharya, Vedanta Desikan.
Vedanta Desikan was a prolific author, composing works like the Rahasyatraya Sara which I discuss here. And although the split between Thenkalais and Vadakalais (which I discuss in this answer) didn't exist in his day, it was Vedanta Desikan's views that would ultimately form the basis of Vadakalai Sri Vaishnavism. In any case, Sri Vaishnavas believe that Vedanta Desikan is an incarnation of the bell found in the shrine of the world-renowned Tirumala Venkateshwara temple in Tirupati. The story is told in this web page:
As ordered by the Lord of Tiruvenkatam and Padmavati Thayar, the couple went on a pilgrimage to Tirumalai. The Lord appeared in their dreams in the garb of a Srivaishnava youth and handed over a small golden bell which Totaramba swallowed. Next morning, when they compared notes, they were astonished to find how both of them had the same dream which concurred in every detail. As the Archaka opened the doors of the Sanctum Sanctorum, he found the bell missing. During an investigation ordered into the loss of the bell, the Lord appeared by Avesa (spiritual trance) on Tirumalai Nambi and told that He had himself presented the bell to the Ananthasuri couple and thenceforward, the small hand- bell need not be used in the Tiruvaradhana in the temple. Even today. when the Naivedyam is offered to the lord, IT IS ONLY THE HUGE BELL suspended in the front hall that is being rung.
Indeed, to this day, there is no bell that is rung inside the shrine of Venkateshwara. So my question is, what is the earliest reference to this story of Vedanta Desikan being an incarnation of Venkateshwara's bell? Do the records of the Tirupati temple mention this incident of the bell disappearing?
Also, on a side note what's the origin of this bell? Was it a divine bell that Vishnu brought with him when he came to Earth as Venkateshwara? Or is it man-made? I'm assuming it's divine, but are there any scriptures that mention this bell?