On Wed, Nov 6, 2019 at 12:08 AM, Dennis Tillman W7PF wrote:
Thanks for that information.
I guess I should have made the following disclosure:
About a year ago, I acquired a 7104 with option 2. My first 7104 didn't have that.
This 7104 with 2 x 7A29 (one has option 4) and a 7B15 (no 7B10) is in an absolutely pristine condition: The painted parts of the case are still silky dull all over, not the local leathery look that develops from touching, even the bent and cut edges are still covered in paint, no Al shining through. It definitely has *not* been repainted, as can be seen when inspecting the inside of the panels and it matches the overall condition. No dust, it has obviously been stored in the dark (no yellowing of buttons, no paint abrasion of printed texts on buttons). Very late series. And of course, the MCP CRT has virtually no traces of use. The inside of the instrument looks absolutely new.
Obviously, a like-new service manual was included.
The instrument was "used" in a university-affiliated lab, where it was kept in a closet, only to be brought out when necessary for some job and returned immediately afterward. I guess they realized the cost and vulnerability of the toy. The only things missing were the original cardboard box and packaging materials....
I'm keeping it in a dark place that's actually more like a vault...
Re. the OCXOVT-BV5 ovenized oscillator: I also bought a few (4) some years ago and used one as the time base in my 2252 portable 'scope. In that 'scope the PLL circuits had failed. A simple phase detector built with a 74LS86 EXOR gate as an external replacement sorted that out.