max@eros.uucp (Max Hauser) (10/05/87)
Jeff Segawa and I concur on the importance of an informed public to deal with pernicious specsmanship. Now as far a potted modules, I post a followup because this may be of interest to others too. In article <907@uhccux.UUCP> cm450s02@uhccux.UUCP (jeff t. segawa) writes: >By the way, what is Dynasolve, and how do I get small batches of it? >I'm curious to see what's inside those old Mark Levinson and >Audio Research modules. Dynasolve (tm) 160 is a proprietary epoxy solvent that depolymerizes the plastic and causes it to flake away. It is very handy for finding out what is inside of cast epoxy modules. By the way, if the manufacturer of the module is small or amateurish, they may not be using epoxy at all but a simpler polymer like an acrylic or styrene. These are less inert than cast epoxy and can be dissolved with more-readily-available organic solvents, obtainable from plastics shops. I regret that I can't remember the manufacturer of Dynasolve; it was several years ago as I said (and there may be different products now). It was one of the firms specializing in chemicals for electronic manufacturing (GC?). In any event it is simple enough to find out, by the means one normally uses to locate a product: either ask an industrial dealer who carries similar things, or look it up in the Thomas Register (in any public or institutional library). My application was reverse-engineering commercial analog function modules (op amps and the like), and also one or two early dbx products as I recall, purely for my own interest. The Dynasolve (a liter would handle six or eight typical brownie-sized modules) is exotic stuff, very toxic, and must be handled with some care (cast epoxy is strong as steel and so hard to depolymerize that many engineers are unaware it can even be done). Among other things, if the epoxy module contains any transistors in epoxy packages (like TO-105 or -106 packages) -- and most op amps did, at that time -- then the epoxy top of the package dissolves too and you see the transistor die and bonding wires, naked on their ceramic header. It can also make resistor color bands hard to see, but you can still easily obtain the schematic diagram, and often the component values as well. I bet that once you get them opened, you will be shocked at the low technology inside (like Dick Pierce and I both were). Max Hauser / max@eros.berkeley.edu / ...{!decvax}!ucbvax!eros!max