Prism DS with a Weak Dewar Vacuum ( Can it be saved :O )

[MrSheep]

I currently have a Prism DS that I would like to attempt to save. Given that it is a for parts camera already, I would like to take the opportunity to experiment on it.
It has a gold tube that houses the PtSi Detector (320x244) what a weird and interesting array. Normally I would expect an InSb FPA for MWIR (3-5um) but I guess it is what they decided to go with back in 1995.

The issue with this camera is that when trying to cool down the cooler runs, however it never reaches the set point also when touching the dewar window/tube it is cold (Not enough to frost over though). Also I don't see any frosting inside when it runs. Was told there was a weak vacuum or no vacuum.
I wonder if the weak vacuum has to do with the Janky soldering of the tube itself. Newer designs of the Prism DS no longer use the gold tube but a solid metal tube more commonly seen today.

This camera uses the same Linear Cryocooler found in the Amber Radiance 1/Radiance HS Cameras. The Hughes 7060H-26S

P.S. I will probably post the control/power boards I have at a later time. They are in pretty good shape still!

[Spirit532]

This definitely looks like either a prototype or first run to me. That soldering is absolutely hand-done, and I would dare guess that it might actually even be regular solder.
If it's soft enough to slice off a couple chunks with a scalpel, stick it on a soldering iron and crank up the temp slowly to see where it melts

[MrSheep]

Yes my thoughts exactly! This must have been a prototype model! The newer version of the Prism DS looks way more professional. I think it is RF or laser welded.

And haha good idea! Doesn't really look like the high silver content solder you normally see.

Also do you know what the nylon ring is on the dewar near the pinch off tube. I see this on many IDCCA's my guess is that it is to stabilize the Dewar PCB?

[Spirit532]

Yes, it's just mechanical. Can be taken off with no problem.

[IR_Geek]

as long as the compressor doesn't sound like it's banging, then it probably is a weak vacuum.

as for PtSi vs. InSb.   InSb was harder to process, more sensitive, and more costly.   With that being a hand held camera they were going for cheaper.    Of course cheaper in this case is relative.  100K+  vs. 30K-50K

[MrSheep]

Yeah I am leaning towards weak vacuum.

And that is nice to know and very interesting indeed.

[MrSheep]

Interesting picture they have on this page. Is that an inductive heater I see? I am guessing they working on a test dewar.

https://ricor.com/innovations/ricors-rotary-cryocoolers-development-and-optimization-for-hot-ir-detectors/

[MrSheep]

Also found this cool teardown of a dewar assembly:

https://xdevs.com/article/sti/

Also I finally found what a NEG (Non-Evaporable Getter) looks like inside the vacuum dewar. Probably a similar getter in my dewar (grey resistor looking thing)

[MrSheep]

Found this nice little snippet about PtSi vs InSb in the Amber Radiance HS brochure