Libor:
I know several groups in several different countries in South America who would love to have some instruments that work, even older ones. They are desparate for instrumentation because it costs many times more for them to get an ADCP due to duties, unstable currencies, etc. In some cases the cost of an ADCP would be 3 times the salary for a well-trained professional.
I could make some inquiries with them about it and see if they or someone they know could assist you. For one example, the current secretary general of WMO is the former Director of the Argentinean National Meteorological Service and is known to several people who work with me in hydroacoustics.