Author Topic: electrophysics 7290a vidicon thermal camera - no image  (Read 1835 times)

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Offline elador

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electrophysics 7290a vidicon thermal camera - no image
« on: August 31, 2015, 10:51:24 pm »
hello
camera doesn't work anymore after a week of outdoor field test
i suspect a power issue
anyone has data? scheme? anything that will help me start diagnose the problem
is there any recommendation where to start?














« Last Edit: September 01, 2015, 08:01:36 am by elador »
 

Offline Fraser

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Re: electrophysics 7290a vidicon thermal camera - no image
« Reply #1 on: October 04, 2015, 07:23:30 pm »
I do not have this camera but I do own an EEV ARGUS 1 that also uses a Pyroelectric Vidicon tube. I have the full service manual and schematics for the ARGUS so can tell you voltages to expect on the tube pins. The camera is very similar to a conventional Vidicon camera but it has a chopper wheel spinning in front of the tube to 'rest' the tube front face. These cameras would suffer chopper wheel and PSU related failures. Normally relatively easy to repair.

Be aware that as the camera is quite old now, the bias voltages on the tube will likely need adjusting for best image. I have those details for the ARGUS tube as well. Marconi/EEV made most of the Pyrovidicon tubes so your camera likely uses one either similar of the same as the EEV ARGUS.

Fraser
 

Offline Fraser

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Re: electrophysics 7290a vidicon thermal camera - no image
« Reply #2 on: October 04, 2015, 07:28:31 pm »
With regard to service manuals and schematics for early thermal cameras, some manufacturers try to be helpful but most decline to share such information with the public. I had to reverse engineer my FLIR PM570 for that reason. Thermal imaging is a topic for which very little deep technical information exists on the NET.

Fraser
 

Offline singapol

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Re: electrophysics 7290a vidicon thermal camera - no image
« Reply #3 on: October 04, 2015, 08:18:38 pm »
Start checking the esr and capacitance of the electrolytic caps and tantalums, especially the electrolytic cap on the round pcb of the tube. ;)
 


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