update:
got the unit, almost in one piece - the package had a nasty accident - the only damage was a broken plastic knob on the handle, nothing to complain about.
the unit is very clean ( even the fan - it got 4 pins ? and not very loud ) - looks like it was kept in an lab / university environment - there are some dBm conversion formulas taped on top.
got full schematics in perfect condition - i'll try to scan them sometime in the future - over 100 pages, and some schematics are almost a meter long. i've browsed them and they give a lot of debugging info - every bit is very well explained + there are a lot of tables for the digital section - enough info to be able to rebuild it from scratch if it ever fails.
got it running - i have some RF signals out and the interface is responding / played a little with the attenuators and FM modulation - the DS1052 frequency counter can work up to 380MHz
took a peek inside - it stinks of blown electrolytic capacitors - and 2 from the power supply blew their caps long ago.
i've seen some strange deposits on all 2.54 headers - some white crystals, almost look like snow - only on those connectors
no other traces of corrosion - i don't know how those caps blew up without any damage
there is no EEPROM inside - this version uses a 8049 microcontroller with 2K of ROM and an external RAM chip + a dedicated GPIB contoler.
the unit is built like a brick - 15 kg , thick aluminum bars / sheet metal all over, and each sub-module got at least an extra layer of shielding - all internal RF connections are made with rigid coax. the best part is an included raiser board - so i can debug each module outside the unit
there are 2 blocks that look to be kept at a controlled temperature - the local oscillator embedded in a big aluminium block and on a board that got some cavity filters a shielded box filled with foam that looked like it had melted.
most of the IC's are from 1978-1980 ... older than me
- there are no signs that it was ever repaired, or even opened in the last 20 years
no photos for now, i'll make a short tear-down when i replace all big PSU caps.
also, i've seen a lot of ~ small caps that look like they've been molded in Bakelite - brown color with inscriptions like "470/16" and polarity markings on top.
the "strange" caps look like these:
http://www.schenk-audio.de/JogisForum/ROE_rote_Becher.jpgshould I try to replace as many as possible ? or just go for the PSU ones first and then replace the others only when they fail ?