Electrophysics 7290 IR camera schematic / service manual?

[Phil Hobbs]

Hi, all,

I have one of these nice lead salt vidicon cameras, good from about
700-1900 nm, but it's on the fritz with a blank image. Fiddling with
the +300V adjust pot will make the image appear for a few tenths of a
second, so it looks like the tube's fine and there's some resistor
that's out of spec and offsetting the bias someplace.

All the power supplies look fine--apart from the +300, they're all
78xx/79xx regulators, so it's easy to check. I have the user manual,
which talks briefly about all the adjustment pots, but after going
through their abbreviated procedure, it's still flatline.

It's all through-hole, so I can probably do OK without a schematic, but
before I spend a day on it, does anybody have a lead on a schematic?
(It's the 7290, not the 7290A.)

Sofradir (formerly Electrophysics) hasn't responded to my query.

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[cha...@gmail.com]

Hello Dr. Hobbs,
I was pleasantly surprised to come across a post on this topic from someone of your stature! Gives me an opportunity to communicate, which is neat. I'm friends with Jan Hall here in Boulder by the way, who has sung your praises around me more than once. Great stuff you've done, and documented, thanks.

I just snagged a 1993 vintage Electrophysics camera off of eBay, which, at long last, proves to actually have a superb 'extended-IR' tube installed in it. I've been trying to find one for several years, as our long-term loan of such a camera from our friends at Lockheed Martin Coherent Technologies is getting tiresome...anyhow, I'm currently trying to round up the identity/source of the rather unusual 4-pin power connector they used on that camera; I may just have to hard-wire it to a 'wall wart', which wouldn't be the end of the world. I don't have schematics unfortunately, but I do at least now have a good connection with a lady named Lorraine Connell at Sofradir, who might be able to help you (if you still need it--). It sort of gives me hope that you actually NEED the schematic; I would have thought you'd just lay hands on it and get it going without one! No way could I, that's for sure :) By the way, our use of such cameras have to do with work at 2050 nm, developing Ho-doped YLF lasers and coherent laser radar systems around them. --Charley Hale, Beyond Photonics LLC (303) 475-2088, cha...@beyondphotonics.com, www.beyondphotonics.com

[Phil Hobbs]

Hi, Charley,

Thanks. Obviously my PR machine has been working better than I thought. ;)

I've been in touch with the estimable Ms. Connell in the past, and she
was most pleasant and helpful but didn't have the manual with schematics
for this version. They're not that expensive on eBay when you can find
one, so I'll probably just get another when it comes up, and save the
tube for a spare.

Say 'Hi' to Jan for me--he's a very generous man as well as a very great
instruments-builder. (I have a few technical heroes, such as R. V.
Jones and Edwin H. Armstrong, and he's high on the list.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com