One very important servicing note to remeber with this unit module is: If you remove the rear cover while the power is on or plugged in you will destroy all DVI programing inside the DVI (Digital Input Module). The only way to restore the programming is to send that module to JVC. There is a light sensor inside the TV and when the back is removed with the power on the data is electronically erased from the eprom. First turn off the set and remove power cord, then short pins 1 and 2 on the SB connector of the digital input module. Before the rear panel is insterted into the cabinet remove the short on the SB connector. DO NOT TURN POWER ON until the rear panel is inserted into the cabinet. If you have to work inside the set with power on remove the two cables going to the DVI module.
That said, if you merely accessed the front panel and changed the convergence amps, re-installed that board, and cannot seem to restore convergence - then you have a secondary problem, probably one or more of the feed resistors on the amp in that circuit have failed.
If everything appears okay and you are able to align convergence in the customer menu then the only last step to storing the setup is to press enter and then exit the convergence menu.
If the info is still not being stored you still have a problem on the convergence board and probably with a resistor or two. There are a series of 1.5 and 2.2 ohm resistors 1w on that board. Take-out your trusty DMM and test each one for open condition or change in value and replace any suspected.