Velugotivaari Vamsavali presents a story – Sriranga, the nephew of the Vijayanagar Emperor raises a banner of rebellion against his emperor and joins the Bijapur camp which resulted in a devastating war for Vijayanagar and Venkata had to hide in the forests where he passed away. On hearing the news, Sriranga abandoned the camp and declared himself the Vijayanagar Emperor. There are two major incongruties in this story – Why will the heir apparent and a seasoned warrior rebel? If a person came out of the enemy camp and declared himself as the emperor, why was there no rebellion immediately?
Another story goes thus – Tirumala Nayaka of Madurai, in an effort to assert his independence from Vijayanagara under Venkata made a common cause with the Nayaks of Tanjore and Gingee and possibly, the Velama Chiefs of Chandragiri and Chengalpattu. The Nayak of Tanjore chickened out at the last minute and led the royal armies over Gingee. In return, Tirumala Nayak invited a Golconda invasion.
How much of this is true, none knows, but one thing is clear – the royal family and others are not friends.
Sriranga had his headquarters at Chandragiri controlling virtually all of the northern borders with Golconda. Just beneath him are the Damerla Chieftains based at Srikalahasti. The emperor had his base at Narayanavanam. Was the issue because of border disputes, of personal interests, of the overall strategy facing the enemy, ego arising out of  difference in age(clearly Sriranga is a very young one, no more than 30 or 35) or anything, no one can tell.
Once on throne, it seems that Damerla Venkata was discovered intriguing with Golconda and Sriranga sacked him, replacing him with a person by name Mallayya or Chinnanna Chetty. The selection was made due to the goodwill he held with the Dutch and other foreigners who can help the Emperor’s cause by supplying mercenaries. To control his feudatories and to tackle the Golconda menace, Sriranga opened talks with Bijapur.
Mallayya was sent to Udayagiri with a strong force to take the fortress. Mallayya is bought by Mir Jumla and Sriranga lost the round.
Bijapur decides to support Mir Jumla, the field commander of Golconda. Even the imperial capital of Vellore came under a seige.
With Bijapur changing sides, Ikkeri, Basavapatna and Chitaldurg had to hold the frontier, ultimately succumbing to the pressure. Next fell Sira, which was directly under the imperial command.
Mysore under Kanthirava Narasa took a chance and occupied Channapatna and advanced till Hoskote bringing it into direct fight with Bijapur. Because of this, Mysore was forced to support Vijayanagar in it’s fight.
Due to the dual invasion, Sriranga had to place his forces divided at Chandragiri and Vellore.
Bijapur forces were defeated at Gudiyattam but were able to advance on Vellore, linking with the Golconda forces. Vellore fell and Sriranga was confined to Chandragiri.
Tirumala Nayaka of Madurai invited Bijapur then to take Gingee which he coveted. But, at the same time, Golconda advanced on Gingee as well. Tirumala Nayaka, at that point, had to join the side of the Nayak of Gingee but was unable to prevent the fall of Gingee.
Sriranga, after passing some time in Gingee and Tanjore, retreated to Mysore.
Fall of Gingee forced all the governors to take the banner of the Emperor. By 1645-6, the Muslim forces were beaten back and Vijayanagar rule extended at least till Nandyal.
Bijapur then took Penugonda and asked Golconda to grant a right of passage from Penugonda to Gingee. It was rejected and Golconda was defeated in war with Bijapur.
At this time, Mir Jumla raises a banner of rebellion and joins Aurangzeb. Instead of handing over the territories he conquered to Abdullah Qutb Shah, he handed over the territories to the Mughal prince.
Sriranga, with no fear of Golconda, advanced and claimed back considerable territory taken over by Mir Jumla. And then, Sriranga drafted a letter to Shah Jehan asking him to accept Vijayanagar as a vassal and if need be, he will convert to Islam. Going by the fact that the Mughal Empire was plunged into a civil war shortly, there is no way to know if this letter ever reached Shah Jehan. But, had this attempt been successful, Vijayanagar would have become another vassal like Bijapur or Golconda and would have become immune to the devastating wars it is seeing daily.
Sriranga tried his luck until pushed back by Golconda. Mir Jumla’s deputy Tupaki Krishnappa inflicted a crushing defeat over Vijayanagar forces in October 1658. Added to this, a general of Sriranga, Koneri Chetti, possibly, the emperor’s father-in-law himself switched sides and along with him, Poonamallee fell. This led to a situation where at least four armies were competing with each other – Mughal Army of Mir Jumla under Tupaki Krishnappa, two Golconda armies, one under Quli Beg and the Vijayanagar Army.
Quli Beg inflicted a crushing defeat over Krishnappa and captured him in 1661.
Bijapur, under Shahaji Bhonsle raided Gingee territory again in 1660.
By 1662, Sriranga was advancing again. By 1664, all the Hindus were uniting under Sriranga for a united front. But, Mysore didn’t join the front. It’s a reverse of the situation now – Madurai under Chokkanatha supporting Vijayanagar and Mysore under Doddadevaraja Wodeyar opposing. Vijayanagar forces involving that of Chokkanatha of Madurai, Vijayaraghava Nayaka of Tanjore, Ekoji, son of Shahaji Bhonsle, Damarla Ayyappa and Sivappa Nayaka of Ikkeri ranged against the Mysore forces under Chikkadevaraja Wodeyar. Chokkanatha withdrew because of a diplomatic onslaught by Mysore and Vijayanagar lost the battle fought at Erode. Damarla Ayyappa, brother of the Nayak of Chengalpattu and Vandavasi was killed. That was the last we hear of Sriranga as an Emperor, though there was another invasion of Mysore by a royal prince Kodandarama who advanced till Hassan in 1674. He is either a nephew or a son of Sriranga. Going by the fact that Shivaji issued a grant to support Sriranga’s widow and two sons, he would have passed away in that period, though his name cropped up till 1704 in Halebid where the last time, the name of a Vijayanagar Emperor came in an inscription –

rajadhiraja paramesvara vira-pratapa sri-Ranga-Raja-Vodeyaru ratna-simhasanarudharagi prithvi-rajyara geyuttiralu Srivatsa-gotrada Asvalayana… Visvesvara-Narasimha-devara Madhya-Manikarnika-tiradalli Srirangapattanakke saluva Haleyabidu-gramavanu adakke saluva grama…

While the maha-rajadhiraja, paramesvara, vira-pratapa, Ranga-Raja-Wodeyar, seated on the jewelled throne was ruling the kingdom of the earth :—a grant ? to the god Visvesvara-Narasimha, of the village of Haleyabidu and its associated hamlets, belonging to Srirangapattana on the bank of the Madhya-Manikarnika.

The bottom line is this. Had all his vassals supported him with everything, Vijayanagar surely wouldn’t have faded away. Who is to blame, the scheming emperor or his assertive vassals, none would know. But, one thing is sure. His capabilities and the way he survived for almost 30 years makes him one of the greatest Vijayanagar Emperors and it’s his bad luck that he did not come during a stable phase.