Don't think any repair manuals were ever produced. The front end module is unrepairable, being potted in epoxy (unless you got a late version without the potting). When it's working, the module nulls out loop offset signals which makes 'scoping the front end a real challenge even if it's unpotted. If the loop is bad, there are probably no replacements available other than scrounging ebay and hoping for the best.
The 1260 is a 30 year old design, I don't even know if we have schematics still kicking around for it. If we do, I'd have no objections to releasing it but customer service dept. has their own policies and generally won't release schematics.
It's a 2-sided board with through-hole components, so with a bit of work you could reverse engineer it (other than the module if it's potted). But without being familiar with metal detectors, not knowing what the signals should look like may make troubleshooting it an exercise in futility. If the problems are something like broken wires or worn potentiometers then you'd have a decent shot at it.
The 1260-X was a very good machine in its day, it changed the industry and quickly became a "classic". Have fond memories of it, it was my first commercial metal detector design. But beepers have come a long ways in the last 30 years, and nowadays just about everything over $150 made in the USA will embarrass it.
As a restoration project, you've got a good one if you didn't pay much for it and can get it to working again. If however your purpose was to get a good metal detector to use, I'd say don't put much effort into trying to repair the thing, if it proves to be difficult give up on it and buy a metal detector of recent manufacture. In our BH line we've got machines down to about $100, and in the Tek and Fisher lines down to about $200. In our low end, two machines in particular stand out as offering good value and passing the "it's almost impossible to find an unhappy customer" test: the BH Tracker 4, and the Tek Delta. The BH TK4 is about $100 and user-friendly, if a bit ugly-- great beginner machine. The Delta ($250-300) will run rings around the 1260 and give you target ID while doing it.
--Dave J.
