First of all, let me state that I am an admirer of Leica bins. I have a pair of UVHD+ and love 'em. I have also owned trinovids and other UVs at various times in the past. I really like the Leica view. I have also owned various Swaros and one of the attractive features about those was the US repair service.
Wish I could say the same about Leica! We (my wife Suzanne and I) recently decided that we were going to send Leica a pair of 25-yr old Trinnies that needed repairs. That was two months ago. The only time since then that they have communicated with us is to confirm that the bins were still under warranty. Good news - yes. However, getting any response or information out of Leica about the progress of repairs, a timeline, or even what they intend doing has been impossible. We have sent several emails and made several calls, and are being stonewalled completely. They NEVER answer emails or calls. This, in my experience is a sad comparison with Swaro.
Leica announced the Leica Trinovid BN series at Photokina in the year 2000. They replaced the Leica Trinovid BA series which came out several years before that. Are yours Leica Trinovid BA series?
http://www.company7.com/leica/news.html#1September2000
You mention above that yours are 25 years old which would mean they were made about 1990-1991.
Could it be a Leitz Trinovid binocular that you sent back to Leica for work? The ones that had Uppendahl prisms?
I have a Leitz 7x42 Trinovid BA Armored and a few years ago I inquired about getting some cleaning and work done on it and Leica told me that many parts for it were no longer available.
Bob