Overhauling 1998 Campagnolo Chorus Ergolevers I'm about to dismantle a 1998 Campag Chorus Ergolever, as I suspect that the G springs need to be changed. I then hope to reassemble them having replaced worn parts. I'm looking for any useful information that supplements what I've already found:


Exploded diagram on Page 41 of Campagnolo's 1998 spare parts catalogue
Video of Overhauling Campagnolo Ergopower Ultrashift 2009


However, there's quite a difference between the components of the 2009 and 1998 levers, so what I'd most like to find is a video showing the disassembly and reassembly of the 1998 levers. Or anything else that you think might help me.

What's wrong with the levers? The rear gears shift to lower sprockets of their own accord. They hold in gear for maybe 20-30 seconds before shifting. I've tried the suggestions from @mikezs in Right campagolo gears slipping. The right-hand lever has almost no audible click - this leads me to suspect the G-springs.
I have managed to overhaul early 2000s Veloce and Mirage, which have the exact same mechanism down to spare part codes, using only the exploded view from the spare parts catalog.

The exploded view looks like an explosion of small parts, but in reality the parts can all be removed and added one at a time, like in the UltraShift video. The mechanisms work on similar principle, the main difference is that the Ergo is disassembled only from the back. If you are only overhauling the index mechanism, you don't need to remove the brake lever. Instead, you pull it back and it exposes a large hex head. Insert a hex key here and it supports the axle (EC-CH135) while you disassemble the rest. For replacing the downshift return spring (EC-RE137) you need to remove the brake lever.

No video, sorry.