Bicycle Mechanics - Unique Shifters assembly on older Cannondale

I would be grateful for some help.
I have an older Cannondale touring bike 1993-94, model T 600.
Down tube shifters popped off (Shimano RX 100) I guess caused from when I had it rebuilt and painted a year ago. (Weird but true, there is an Assembly rod which runs between the two shifters, threads are wasted)
The distance between the two shifters is longer than most bikes because of the huge size of the down tube on the Cannondale. Could you suggest or recommend a replacement game plan for this bike, 7 speeds. I am not sure what would be compatible.

Thank you

Chris

I'd take it to a cdale dealer and see if they have the parts for a fix. Otherwise you may be stuck wih trying to do something with JB weld and a makeshift Bubba fix that may not last.

I cruised by a cd dealer yesterday and a young mechanic said “wow” he had never seen an assembly like mine before, or it was old. Didn’t have a valid suggestion for a fix other than a custom job. I’ll probably check another source.
I am almost thinking the shop that did the rebuild last year had an issue and rigged it.
I saw an older Shimano (105) shifter on ebay and it is held to the frame by Allen bolts. On my down tube there is a large hole on both sides for the shifter and then a much smaller whole, I wonder if an Allen bolt would attach & hold on an aluminum frame?

I cruised by a cd dealer yesterday and a young mechanic said “wow” he had never seen an assembly like mine before, or it was old. Didn’t have a valid suggestion for a fix other than a custom job. That was your problem right there.That assembly was used for years. Maybe you would do better contacting Cdale directly. You can't just stick an allen bolt in that frame hole and expect it to hold.That is why Cdale used the thru bolt.

I was going to suggest bar-end shifters as an alternative but you need those posts to bolt the cable stops.....

I was going to suggest bar-end shifters as an alternative but you need those posts to bolt the cable stops.....Or a clamp on guide of suitable diameter.

That was your problem right there.That assembly was used for years. Maybe you would do better contacting Cdale directly. You can't just stick an allen bolt in that frame hole and expect it to hold.That is why Cdale used the thru bolt.

Thank you, first confirmation I've gotten that this is their proprietary assembly. I actually hit another shop yesterday, not a dealer, and the mechanic gave me the same perplexed look, like I had a bike from Mars. As many of us are not mechanically inclined but love to ride, It is difficult to get straight talk. Chicago has a bike shop on every corner but, I haven't found one with a real experienced shop.
I'll try Cannondale directly.