Jack,
First I'll just comment that while the Bandido, Bandido II and Silver Sabre II in those under-slung housings take 2-9Volt batteries, they can operate just fine on a single 9-V battery. There's not much difference in performance, just a reduced battery-life or run-time.
To open them up, you simply disconnect the coil cable. The remove the two screws on the bottom of the housing and the control panel and circuit board will slide out.. You can only come part-way out because the battery and battery cables are in the holder compartment in the housing, so to pull it out all the way you'll need to remove the batteries and work the battery clips connectors and through the hole in the battery holder.
Let us know how your fix-it job goes.
Monte
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Stinkwater Wells Trading Post
Metal Detector Evaluations and Product Reviews monte@ahrps.org ... or ... monte@stinkwaterwells.com 503-481-8147Detector Outfit: A selection of my favorite makes and models, with the best coils mounted, for the tasks I'll take on.Pinpointers: Pulse-Dive & ProPointer AT .. Headphones: 'Hornet' & 'Wasp' .. MS-3 Z-Lynk .. ML-80 .. N/M Green edition*** All working well today to make memories for tomorrow. ***