Hi, I've recently picked up a couple of SLCR-101s - one working normally, the other sold very cheaply as faulty - it doesn't stay locked for very long. I've not looked at the latter yet in any detail to see what's going on - considering it a side project for now in any case. Unless my google-fu really is awful, I've been unable to find any specific references/data for the SLCR-101s. Empirically they seem to be the same internals as the LPRO-101, just a lower profile lamp assembly. I've found Fred De Vries (PE1FBO) excellent Efratom LPRO-101 reference guide (Rev 6 Jan 2010) as well as the LPRO Users Guide and Integration Guidelines from Datum, who I gather have taken over the product line from Efratom. In both cases the docs have just come from google searches and I've not been able to find the original source, particularly for Fred's guide. Does anyone know of the "upstream" sources for either these LPRO-101 docs and/or have a source for specific SLCR-101 info ? I should add that I've got the units going ok (modulo one being faulty as described) using the LPRO information and got suitable heatsinks from a local company so all good there. I'm thinking I might build up a little supervisory circuit that monitors the various "health" signals and perhaps provides buffered 10MHz sine output. But that's a stretch goal :) Thanks for any pointers on the above. Cheers, Hugh